Andrew Huberman: Neuroscience of Optimal Performance

Lex Fridman (03:12.880)

but you could have stress without fear. And you can't really have trauma without fear and stress,

Lex Fridman (03:18.000)

but you could have fear and stress without trauma. So we can start playing the word game.

Lex Fridman (03:22.080)

And that actually is one of the motivations for even having a laboratory that studies these things

Andrew Huberman (03:26.320)

is that we really need better physiological, neuroscientific, and operational definitions

Andrew Huberman (03:32.720)

of what these things are. I mean, the field of understanding emotions and states, which is mainly

Lex Fridman (03:39.520)

what I'm interested in, is very complicated. But we can do away with a lot of complicated debate

Lex Fridman (03:46.400)

and say in our laboratory, what we're looking for to assign it a value of fear is a big inflection

Andrew Huberman (03:54.960)

in autonomic arousal. So increases in heart rate, increases in breathing, perspiration,

Andrew Huberman (04:00.480)

pupil dilation, all the hallmark signature features of the stress response. And in some cases,

Andrew Huberman (04:07.760)

we have the benefit of getting neurosurgery patients where we've got electrodes in their

Andrew Huberman (04:11.680)

amygdala and their insula and the orbitofrontal cortex down beneath the skull. So these are

Andrew Huberman (04:17.280)

chronically implanted electrodes. We're getting multiunit signals and we can start seeing some

Andrew Huberman (04:22.000)

central features of meaning within the brain. And what's interesting is that as trivial as it might

Andrew Huberman (04:31.360)

seem in listening to it, almost everybody responds to heights and falling from a high virtual place

Andrew Huberman (04:42.320)

with a very strong stress, if not fear response. And that's because the visual vestibular apparatus,

Andrew Huberman (04:49.120)

right? The optic flow and how it links to the balanced semicircular canals of the inner ears,

Andrew Huberman (04:53.920)

all this technical stuff. But really, all of that pulls all your physiology, the feeling that your

Andrew Huberman (05:01.040)

stomach is dropping, the feeling that suddenly you're sweating, even though you're not afraid

Andrew Huberman (05:04.960)

of falling off this virtual platform, but you feel as if you're falling because of the optic flow.

Andrew Huberman (05:10.720)

That one is universal. So we've got a dive with great white sharks experience where you actually

Andrew Huberman (05:16.480)

exit the cage. We went out and did this in the real world and brought back 360 video that's

Andrew Huberman (05:21.600)

built out pretty. Oh, so this is actually 360 video.

Andrew Huberman (05:24.560)

360 video. And this was important to us, right? So when we decided to set up this platform,

Andrew Huberman (05:29.680)

a lot of the motivation was that a lot of the studies of these things in laboratories,

Andrew Huberman (05:35.600)

I don't want to call them lame because I want to be respectful of the people that did this stuff

Andrew Huberman (05:39.040)

before, but they study fear by showing subjects a picture of a bloody arm or a snake or something

Andrew Huberman (05:45.280)

like that. And it just, unless you have a snake phobia, it just wasn't creating a real enough

Andrew Huberman (05:50.560)

experience. So we need to do something where people aren't going to get injured, but where

Andrew Huberman (05:54.080)

we can tap into the physiology and that thing of presence of people momentarily, not the whole time,

Lex Fridman (05:59.120)

but momentarily forgetting they're in a laboratory. And so heights will always do it. And if people

Andrew Huberman (06:06.000)

want to challenge me on this, I like to point to that movie, Free Solo, which was wild because

Andrew Huberman (06:10.880)

it's an incredible movie, but I think a lot of its popularity can be explained by a puzzle,

Andrew Huberman (06:16.960)

which is you knew he was going to live when you walked in the theater or you watched it at home.

Andrew Huberman (06:22.880)

You knew before that he survived. And yet it was still scary that people somehow were able to put

Andrew Huberman (06:28.960)

themselves into that experience or into Alex's experience enough that they were concerned or

Andrew Huberman (06:35.520)

worried or afraid at some level. So heights always does it. If we get people who have generalized

Andrew Huberman (06:41.040)

anxiety, these are people who wake up and move through life at a generally higher state of

Andrew Huberman (06:46.800)

autonomic arousal and anxiety, then we can tip them a little bit more easily with things that

Andrew Huberman (06:51.760)

don't necessarily get everyone afraid. Things like claustrophobia, public speaking, that's

Andrew Huberman (06:58.880)

going to vary from person to person. And then if you're afraid of sharks, like my sister for instance

Andrew Huberman (07:04.240)

is afraid of sharks, she won't even come to my laboratory because there's a thing about sharks

Andrew Huberman (07:08.960)

in it. That's how terrified some people are of these specific stimuli, but heights gets them

Andrew Huberman (07:14.400)

every time. Yeah. And I'm terrified of heights. We have you step off a platform, virtual platform,

Lex Fridman (07:22.400)

and it's a flat floor in my lab, but you're up there. Well, you actually allow them the

Andrew Huberman (07:28.160)

possibility in the virtual world to actually take the leap of faith. Yeah. Maybe I should

Andrew Huberman (07:32.560)

describe a little bit of the experiment. So without giving away too much, in case someone

Andrew Huberman (07:36.800)

wants to be a subject in one of these experiments, we have them playing a cognitive game. It's a

Andrew Huberman (07:41.120)

simple lights out kind of game where you're pointing a cursor and turning out lights on a

Andrew Huberman (07:45.520)

grid, but it gets increasingly complex and it speeds up on them. And there's a failure point

Andrew Huberman (07:50.960)

for everybody where they just can't make the motor commands fast enough. And then we surprise

Andrew Huberman (07:56.560)

people essentially by placing them virtually, all of a sudden they're on a narrow platform between

Andrew Huberman (08:03.040)

two buildings. And then we encourage them or we cue them by talking to them through a microphone

Andrew Huberman (08:10.080)

to continue across that platform to continue the game. And some people, they actually will

Andrew Huberman (08:18.480)

get down on the ground and hold onto a virtual beam that doesn't even exist on a flat floor.

Lex Fridman (08:24.080)

And so what this really tells us is the power of the brain to enter these virtual states as if

Andrew Huberman (08:29.840)

they were real. And we really think that anchoring the visual and the vestibular, the balance

Andrew Huberman (08:35.040)

components of the nervous system are what bring people into that presence so quickly.

Andrew Huberman (08:40.000)

There's also the potential, and we haven't done this yet to bring in 360 sound.

Lex Fridman (08:44.320)

So the reason we did 360 video is when we started all this back in 2016,

Andrew Huberman (08:49.200)

a lot of the VR was pretty lame, frankly, it was CGI, it just wasn't real enough. But with 360

Andrew Huberman (08:55.760)

video, we knew that we could get people into this presence where they think they're in a real

Andrew Huberman (08:59.840)

experience more quickly. And our friend Michael Muller, who I was introduced to because of the

Andrew Huberman (09:04.320)

project, I reached out to some friends. Michael Muller is a very famous portrait

Andrew Huberman (09:08.160)

photographer in Hollywood, but he dives with great white sharks and he leaves the cage.

Lex Fridman (09:12.400)

And so we worked with him to build a 360 video apparatus that we could swim underwater with,

Andrew Huberman (09:19.920)

went out to Guadalupe Island, Mexico, and actually got the experience. It was a lot of fun. There's

Andrew Huberman (09:25.600)

some interesting moments out there of danger, but it came back with that video and built that for

Andrew Huberman (09:30.240)

the sharks. And then we realized we need to do this for everything. We need to do it for heights. We

Andrew Huberman (09:33.440)

need to do it for public speaking, for claustrophobia. And what's missing still is 360 sound where 360

Andrew Huberman (09:40.880)

sound would be, for instance, if I were to turn around and there was a giant attack dog there,

Andrew Huberman (09:47.920)

the moment I would turn around and see it, the dog would growl. But if I turn back toward you,

Andrew Huberman (09:52.560)

then it would be silent. And that brings a very real element to one's own behavior where you

Andrew Huberman (09:58.720)

don't know what's going to happen if you turn a corner. Whereas if there's a dog growling behind

Andrew Huberman (10:03.040)

me and I turn around and then I turn back to you and it's still growling, that might seem like more

Andrew Huberman (10:08.800)

of an impending threat and sustained threat, but actually it's when you start linking your own body

Andrew Huberman (10:15.040)

movements to the experience. So when it's closed loop where my movements and choices are starting

Andrew Huberman (10:20.320)

to influence things and they're getting scarier and scarier, that's when you can really drive

Andrew Huberman (10:25.120)

people's nervous system down these paths of high states of stress and fear. Now we don't want to

Andrew Huberman (10:30.400)

traumatize people obviously, but we also study a number of tools that allow them to calm themselves

Andrew Huberman (10:36.480)

in these environments. So the short answer is height. Well, from a psychology and from a neuroscience

Andrew Huberman (10:43.760)

perspective, this whole construction that you've developed is fascinating. We did this a little

Andrew Huberman (10:49.200)

bit with autonomous vehicles. So to try to understand the decision making process of a

Andrew Huberman (10:56.480)

pedestrian when they cross the road and trying to create an experience of a car, you know, that

Andrew Huberman (11:02.720)

could run you over. So there's the danger there. I was so surprised how real that whole world was.

Lex Fridman (11:11.680)

And the graphics that we built wasn't ultra realistic or anything, but I was still afraid

Andrew Huberman (11:17.440)

of being hit by a car. Everybody we tested were really afraid of being hit by that car.

Lex Fridman (11:21.920)

Even though it was all a simulation.

Andrew Huberman (11:23.120)

It was all a simulation. It was kind of boxy actually. I mean, it wasn't like ultra realistic

Lex Fridman (11:29.200)

simulation. It was fascinating. Looms and heights. So any kind of depth,

Andrew Huberman (11:35.520)

we're just programmed to not necessarily recoil, but to be cautious about that edge and that depth.

Lex Fridman (11:43.360)

And then looms, things coming at us that are getting larger. There are looming sensing neurons

Andrew Huberman (11:47.440)

even in the retina at a very, very early stage of visual processing. And incidentally, the way

Andrew Huberman (11:54.640)

Muller and folks learn how to not get eaten by great white sharks when you're swimming outside

Andrew Huberman (12:00.640)

the cage is as they start lumbering in, you swim toward them. And they get very confused when you

Andrew Huberman (12:06.080)

loom on them because clearly you're smaller. Clearly they could eat you if they wanted to,

Lex Fridman (12:11.360)

but there's something about forward movement toward any creature that that creature questions

Andrew Huberman (12:16.960)

whether or not it would be a good idea to generate forward movement toward you. And so that's

Andrew Huberman (12:22.240)

actually the survival tool of these cage exit white shark divers. Are you playing around with,

Andrew Huberman (12:27.120)

like one of the critical things for the autonomous vehicle research is you couldn't do 360 video

Andrew Huberman (12:32.320)

because there's a game theoretic. There's an interactive element that's really necessary.

Lex Fridman (12:37.120)

So maybe people realize this, maybe they don't, but 360 video, you obviously,

Andrew Huberman (12:44.400)

well, it's actually not that obvious to people, but you can't change the reality that you're

Andrew Huberman (12:48.880)

watching. That's right. So, but you find that that's like, is there something fundamental

Andrew Huberman (12:55.840)

about fear and stress that the interactive element is essential for, or do you find you can,

Andrew Huberman (13:02.720)

you can arouse people with just the video? Great question. It works best to use mixed

Andrew Huberman (13:08.240)

reality. So we have a snake stimulus that I personally don't like snakes at all. I don't

Andrew Huberman (13:13.600)

mind spiders. We also have a spider stimulus, but like snakes, I just don't like them. There's

Andrew Huberman (13:17.840)

something about the, the slithering and the, it just creates a visceral response for me.

Andrew Huberman (13:23.840)

Some people not so much, and they have lower levels of stress and fear in there. But one way

Andrew Huberman (13:29.040)

that we can get them to feel more of that is to use mixed reality where we have an actual physical

Andrew Huberman (13:36.000)

bat and they have to stomp out the snake as opposed to just walk to a little safe corner,

Andrew Huberman (13:42.240)

which then makes the snake disappear. That tends to be not as stressful as if they have

Andrew Huberman (13:46.800)

a physical weapon. And so you've got people in there, you know, banging on the floor against

Andrew Huberman (13:50.640)

this thing. And there's something about engaging that makes it more of a, more of a threat. Now,

Andrew Huberman (13:56.400)

I should also mention that we, we always get the subjective report from the subject of what they

Andrew Huberman (14:01.680)

experienced because we never want to project our own ideas about what they were feeling,

Lex Fridman (14:06.400)

but that's the beauty of working with humans is you can ask them how they feel and humans aren't

Andrew Huberman (14:11.120)

great at explaining how they feel. But it's a lot easier to understand what they're saying than a

Andrew Huberman (14:16.880)

mouse or a macaque monkey is saying. So it's the best we can do is language plus these physiological

Lex Fridman (14:23.840)

and neurophysiological signals. Is there something you've learned about yourself about your deepest

Andrew Huberman (14:28.080)

fears? Like you said, snakes, is there something that, like if I were to torture you, I'm, so I'm

Andrew Huberman (14:34.240)

Russian. So, you know, I always kind of think, how can I murder this people that this person

Andrew Huberman (14:40.240)

entered the room, but also how, how can I torture you to get some information out of you? What would

Andrew Huberman (14:46.720)

I go with? Hmm. It's interesting. You should say that I never considered myself claustrophobic,

Lex Fridman (14:51.760)

but because I don't mind small environments provided they're well ventilated. But I,

Andrew Huberman (14:58.960)

before COVID, I started going to this Russian banya, you know, and then, and I had never been

Andrew Huberman (15:04.320)

to a banya. So, you know, the whole experience of really, really hot sauna and what are they

Andrew Huberman (15:09.440)

called? The plots. They're hitting you with the leaves and it gets really hot and humid in there.

Lex Fridman (15:14.960)

And there were a couple of times where I thought, okay, this thing is below ground.

Andrew Huberman (15:20.320)

It's in a city where there are a lot of earthquakes. Like if this place crumbled and

Andrew Huberman (15:26.080)

we were stuck in here and I'd start getting a little panicky and I realized, I'm like, I don't

Andrew Huberman (15:29.840)

like small confined spaces with poor ventilation. So I realized I think I have some claustrophobia

Lex Fridman (15:35.440)

and I wasn't aware of that before. So I've put myself into our own claustrophobia stimulus,

Andrew Huberman (15:41.120)

which involves getting into an elevator and with a bunch of people, virtual people,

Lex Fridman (15:46.960)

and the elevator gets stalled. And at first you're fine. You feel fine. But then as we start

Andrew Huberman (15:53.040)

modulating the environment and we actually can control levels of oxygen in the environment,

Andrew Huberman (15:57.520)

if we want to, it is really uncomfortable for me. And I never would have thought, you know, I fly,

Andrew Huberman (16:03.680)

I'm comfortable in planes, but it is really uncomfortable. And so I think I've unhatched

Andrew Huberman (16:09.760)

a bit of a claustrophobia. Yeah. Yeah. Yeah. For me as well, probably that one, that one is pretty

Andrew Huberman (16:15.760)

bad. The heights I tried to overcome. So I went to skydiving to try to overcome the fear of heights,

Lex Fridman (16:21.840)

but that didn't help. Did you jump out? Yeah. Yeah. I jumped out, but it was, it was a,

Andrew Huberman (16:26.240)

it was fundamentally different experience. And I guess there could be a lot of different flavors

Andrew Huberman (16:32.240)

of fear of heights maybe, but the one I have didn't seem to be connected to jumping out of a

Andrew Huberman (16:39.920)

plane is a very different, cause like once you accept that you're going to jump, then it's,

Andrew Huberman (16:45.840)

it's a different thing. I think what I'm afraid of is the moments before it is the scariest part.

Andrew Huberman (16:54.720)

Absolutely. And I don't think that's emphasized in the skydiving experience as much,

Lex Fridman (16:59.840)

and also just the acceptance of the fact that it's going to happen. So once you accept that

Andrew Huberman (17:05.200)

it's going to happen, it's not as scary. It's the fact that it's not supposed to happen.

Lex Fridman (17:10.240)

And it might, that's the scary part that I guess I'm not being eloquent in this description,

Lex Fridman (17:15.440)

but there's something about skydiving that was actually philosophically liberating. I was,

Andrew Huberman (17:21.040)

I was like, wow, it, it was the possibility that you can walk on a surface. And then at a certain

Andrew Huberman (17:28.480)

point there's no surface anymore to walk on. And it's all of a sudden the world becomes

Andrew Huberman (17:33.440)

three dimensional and there's this freedom of floating that the concept of like of earth

Andrew Huberman (17:40.800)

disappears for a brief few seconds. I don't know. That was, that was wild. That was wild,

Lex Fridman (17:46.320)

but I'm still terrified of heights. So, I mean, one, one thing I want to ask just on fear,

Lex Fridman (17:52.240)

cause it's so fascinating is have you learned anything about what it takes to overcome fears?

Lex Fridman (18:00.160)

Yes. And that comes from two, from a, you know, research study standpoint,

Andrew Huberman (18:05.440)

two parallel tracks of research. One was done actually in mice, because we have a mouse lab

Andrew Huberman (18:10.800)

also where we can probe around in different brain areas and try and figure out what interesting

Andrew Huberman (18:14.560)

brain areas we might want to probe around in humans. And a graduate student in my lab,

Andrew Huberman (18:19.840)

she's now at Caltech, Lindsay Saleh, published a paper back in 2018, showing that what at first

Andrew Huberman (18:27.920)

might seem a little bit obvious, but the mechanisms are not, which is that there are really three

Andrew Huberman (18:32.720)

responses to fear. You can pause, you can freeze essentially. You can retreat, you can back up,

Andrew Huberman (18:39.120)

or you can go forward. And there's a single hub of neurons in the midbrain, it's actually not

Andrew Huberman (18:46.400)

the midbrain, but it's in the middle of the thalamus, which is a forebrain structure.

Lex Fridman (18:51.680)

And depending on which neurons are active there, there's a much higher probability that a mouse,

Andrew Huberman (18:56.560)

or it turns out, or a human will advance in the face of fear or will pause or will retreat.

Andrew Huberman (19:02.880)

Now that just assigns a neural structure to a behavioral phenomenon. But what's interesting

Andrew Huberman (19:08.080)

is that it turns out that the lowest level of stress or autonomic arousal is actually associated

Andrew Huberman (19:14.480)

with the pausing and freezing response. Then as the threat becomes more impending, and we used

Andrew Huberman (19:21.040)

visual looms in this case, the retreat response has a slightly higher level of autonomic arousal

Lex Fridman (19:28.000)

and stress. So think about playing hide and go seeking, you're trying to stay quiet in a closet

Andrew Huberman (19:33.520)

that you're hiding. If you're very calm, it's easy to stay quiet and still. As your level of stress

Andrew Huberman (19:38.400)

goes up, it's harder to maintain that level of quiet and stillness. You see this also in animals

Andrew Huberman (19:45.040)

that are stalking, a cat will chatter its teeth. That's actually sort of top down inhibition and

Andrew Huberman (19:49.680)

trying to restrain behavior. So the freeze response is actually an active response,

Lex Fridman (19:54.800)

but it's fairly low stress. And what was interesting to us is that the highest level

Andrew Huberman (19:59.440)

of autonomic arousal was associated with the forward movement toward the threat. So in your case,

Andrew Huberman (1:00:01.120)

it, but obviously the ventriloquist doesn't throw their voice. What they do is they direct your

Andrew Huberman (1:00:06.080)

vision to a particular location and you think the sound is coming from that location. And there are

Andrew Huberman (1:00:10.560)

beautiful experiments that Greg and his colleagues have done where they suddenly introduce an

Andrew Huberman (1:00:13.840)

auditory visual mismatch and it freaks people out because you can actually make it seem from a

Andrew Huberman (1:00:20.000)

perception standpoint as if the sound arrived from the corner of the room and hit you physically and

Andrew Huberman (1:00:26.560)

people will recoil. And so sounds aren't getting thrown across the room. They're still coming from

Andrew Huberman (1:00:31.840)

a defined location, an array of speakers, but this is the way the brain creates these internal

Andrew Huberman (1:00:37.680)

representations. And again, I don't want to go down a rabbit hole, but I'm sure the listeners

Andrew Huberman (1:00:46.800)

appreciate this, but everything in the brain is an abstraction, right? I mean, the sensory

Andrew Huberman (1:00:53.200)

apparatus, there are the eyes and ears and nose and skin and taste and all that are taking

Andrew Huberman (1:00:58.080)

information and with interoception, taking information from sensors inside the body,

Andrew Huberman (1:01:03.040)

the enteric nervous system for the gut. I've got sensory neurons that innervate my liver,

Andrew Huberman (1:01:08.160)

um, et cetera, taking all that. And the brain is abstracting that in the same way that if I

Andrew Huberman (1:01:16.960)

took a picture of your face and I handed it to you and I'd say, that's you, you'd say, yeah, that's

Andrew Huberman (1:01:21.120)

me. But if I were an abstract artist, I'd be doing a little bit more of what the brain does, where if

Andrew Huberman (1:01:26.320)

I took a pen, pad and paper, maybe I could do this because I'm a terrible artist and I could just

Andrew Huberman (1:01:30.480)

mix it up. And I, let's say I would make your eyes like water bottles, but I'd flip them upside down

Lex Fridman (1:01:34.720)

and I'd start assigning fruits and objects to the different features of your face. And I show it to

Andrew Huberman (1:01:38.560)

you, I say, Lex, that's you say, well, that's not me. And I'd say, no, but that's my abstraction

Andrew Huberman (1:01:42.240)

of you. But that's what the brain does. The space time relationship of the neurons that fire that

Andrew Huberman (1:01:47.520)

encode your face has have no resemblance to your face. Right. And I think people don't really,

Andrew Huberman (1:01:53.520)

I don't know if people have fully internalized that, but the day that I, and I'm not sure I

Andrew Huberman (1:01:58.400)

fully internalized that because it's weird to think about, but all neurons can do is fire in

Andrew Huberman (1:02:04.320)

space and in time, different neurons in different sequences, perhaps with different intensities.

Andrew Huberman (1:02:08.640)

It's not clear. The action potential is all or none. Although people, neuroscientists don't like

Andrew Huberman (1:02:12.480)

to talk about that, even though it's been published in nature a couple of times, the

Andrew Huberman (1:02:16.160)

action potential for a given neuron doesn't always have the exact same waveform. People,

Andrew Huberman (1:02:20.240)

it's in all the textbooks, but you can modify that waveform.

Andrew Huberman (1:02:23.440)

Well, I mean, there's a lot of fascinating stuff with neuroscience about the fuzziness of all the,

Andrew Huberman (1:02:29.680)

of the transfer of information from neuron to neuron. I mean, we certainly touch upon it every

Andrew Huberman (1:02:35.600)

time we at all try to think about the difference between artificial neural networks and biological

Andrew Huberman (1:02:40.080)

neural networks. But can we maybe linger a little bit on this, on the circuitry that you're getting

Andrew Huberman (1:02:45.920)

at? So the brain is just a bunch of stuff firing and it forms abstractions that are fascinating

Lex Fridman (1:02:53.120)

and beautiful, like layers upon layers upon layers of abstraction. And I think it, just like

Andrew Huberman (1:02:58.480)

when you're programming, you know, I'm programming in Python, it's awe inspiring to think that

Andrew Huberman (1:03:05.680)

underneath it all, it ends up being zeros and ones. And the computer doesn't know about, you know,

Andrew Huberman (1:03:11.360)

stupid Python or Windows or Linux. It only knows about the zeros and ones. In the same way with

Andrew Huberman (1:03:16.880)

the brain, is there something interesting to you or fundamental to you about the circuitry of the

Andrew Huberman (1:03:25.840)

brain that allows for the magic that's in our mind to emerge? How much do we understand? I mean,

Andrew Huberman (1:03:35.200)

maybe even focusing on the vision system, is, is there something specific about the structure of

Lex Fridman (1:03:41.600)

the vision system, the circuitry of it that allows for the complexity of the vision system to emerge?

Lex Fridman (1:03:49.600)

Or is it all just the complete chaotic mess that we don't understand?

Andrew Huberman (1:03:52.400)

It's definitely not all a chaotic mess that we don't understand, if we're talking about vision.

Lex Fridman (1:03:58.160)

And that's not just because I'm a vision scientist.

Lex Fridman (1:04:00.160)

Let's stick to vision.

Andrew Huberman (1:04:01.200)

Let's stick to vision. Well, because in the beauty of the visual system, the reason David Hubel and

Andrew Huberman (1:04:05.520)

Torrance and Wiesel won the Nobel prize was because they were brilliant and forward thinking and

Andrew Huberman (1:04:09.680)

adventurous and all that good stuff. But the reason that the visual system is such a great

Andrew Huberman (1:04:13.680)

model for addressing these kinds of questions and other systems are hard, is we can control

Andrew Huberman (1:04:18.160)

the stimuli. We can adjust spatial frequency, how finer the gratings are, thick gratings,

Andrew Huberman (1:04:23.680)

thin gratings. We can adjust temporal frequency, how fast things are moving. We can use cone

Andrew Huberman (1:04:28.480)

isolating stimuli. We can use it. There's so many things that you can do in a controlled way.

Andrew Huberman (1:04:33.600)

Whereas if we were talking about cognitive encoding, like encoding the space of concepts

Andrew Huberman (1:04:39.200)

or something. I, like you, if I may, am drawn to the big questions.

Andrew Huberman (1:04:46.880)

The big questions in neuroscience. But I confess in part because of some good advice I got early

Andrew Huberman (1:04:53.680)

in my career and in part because I'm not perhaps smart enough to go after the really high level

Andrew Huberman (1:05:01.120)

stuff. I also like to address things that are tractable and we need to address what we can

Andrew Huberman (1:05:10.000)

stand to make some ground on at a given time.

Andrew Huberman (1:05:12.640)

There you can construct brilliant controlled experiments to study, to really literally

Andrew Huberman (1:05:18.880)

answer questions about, yeah.

Andrew Huberman (1:05:20.160)

Yeah. I mean, I'm happy to have a talk about consciousness, but it's a scary talk. And I

Andrew Huberman (1:05:24.880)

think most people don't want to hear what I have to say, which is, we can save that for later,

Lex Fridman (1:05:29.920)

perhaps.

Andrew Huberman (1:05:30.320)

I mean, it's an interesting question of, we talk about psychedelics. We can talk about

Andrew Huberman (1:05:36.400)

consciousness. We can talk about cognition. Can experiments in neuroscience be constructed

Lex Fridman (1:05:43.200)

to shed any kind of light on these questions?

Andrew Huberman (1:05:45.920)

So, I mean, it's cool that vision, I mean, to me, vision is probably one of the most beautiful

Andrew Huberman (1:05:52.080)

things about human beings. Also from the AI side, computer vision has some of the most

Andrew Huberman (1:05:59.040)

exciting applications of neural networks is in computer vision. But it feels like that's a

Andrew Huberman (1:06:04.640)

that's a neighbor of cognition and consciousness. It's just that we maybe haven't come up with

Lex Fridman (1:06:10.000)

experiments to study those yet.

Andrew Huberman (1:06:11.600)

Yeah. The visual system is amazing. We're mostly visual animals to navigate,

Andrew Huberman (1:06:15.680)

survive. Humans mainly rely on vision, not smell or something else, but it's a filter

Andrew Huberman (1:06:22.000)

for cognition and it's a, it's a strong driver of cognition. Maybe just cause it came up and

Andrew Huberman (1:06:28.000)

then we're moving to higher level concepts. Just the way the visual system works can be

Andrew Huberman (1:06:32.880)

summarized in it in a few relatively succinct statements. Unlike most of what I've said,

Lex Fridman (1:06:37.840)

which has not been succinct at all.

Andrew Huberman (1:06:39.200)

Let's go there.

Andrew Huberman (1:06:39.760)

You know, the retina, yeah. So the retina is this three layers of neuron structure at the

Andrew Huberman (1:06:47.200)

back of your eye. It's about as thick as a credit card. It is a piece of your brain.

Lex Fridman (1:06:51.520)

And sometimes people think I'm kind of wriggling by out of a reality by saying that it is,

Andrew Huberman (1:06:56.640)

it's absolutely a piece of the brain. It's, it's a forebrain structure that in the first

Andrew Huberman (1:07:00.080)

trimester, there's a genetic program that made sure that that neural retina, which is part of

Andrew Huberman (1:07:05.920)

your central nervous system was squeezed out into what's called the embryonic eye cups.

Lex Fridman (1:07:10.960)

And that the bone formed with a little hole where the optic nerve is going to connect

Andrew Huberman (1:07:14.480)

it to the rest of the brain. And those, that window into the world is the only window into

Andrew Huberman (1:07:20.160)

the world for a, for a mammal, which has a thick skull. Birds have a thin skull. So their pineal

Andrew Huberman (1:07:24.640)

gland sits and lizards too, and snakes actually have a hole so that light can make it down into

Andrew Huberman (1:07:29.520)

the pineal directly. And in train melatonin rhythms for time of day and time of year,

Andrew Huberman (1:07:33.520)

humans have to do all that through the eyes. So three layers of neurons that are a piece of your

Andrew Huberman (1:07:38.720)

brain, their central nervous system, and the optic nerve connects to the rest of the brain,

Andrew Huberman (1:07:42.800)

the neurons in the eye, somewhat just care about luminance, just how bright or dim it is.

Lex Fridman (1:07:48.080)

And they inform the brain about time of day. And then the central circadian clock informs every

Andrew Huberman (1:07:52.160)

cell in your body about time of day and make sure that all sorts of good stuff happens. If you're

Andrew Huberman (1:07:55.760)

getting light in your eyes at the right times and all sorts of bad things happen. If you are getting

Andrew Huberman (1:07:59.760)

light randomly throughout the 24 hour cycle, we could talk about all that, but this is a good

Andrew Huberman (1:08:04.080)

incentive for keeping a relatively normal schedule, consistent schedule, light exposure,

Andrew Huberman (1:08:10.720)

consistent schedule, try and keep a consistent schedule. When you're young, it's easy to go off

Andrew Huberman (1:08:15.840)

schedule and recover. As you get older, it gets harder, but you see everything from outcomes in

Andrew Huberman (1:08:20.480)

cancer patients to diabetes improves when people are getting light at a particular time of day and

Andrew Huberman (1:08:29.280)

getting darkness at a particular phase of the 24 hour cycle. We were designed to get light and

Andrew Huberman (1:08:36.400)

dark at different times of the circadian cycle. All that information is coming in through

Andrew Huberman (1:08:42.560)

specialized type of neuron in the retina called the melanopsin intrinsically photosensitive

Andrew Huberman (1:08:46.240)

ganglion cell discovered by David Berson at Brown University. That's not spatial information. It's

Andrew Huberman (1:08:53.040)

subconscious. You don't think, Oh, it's daytime. Even if you're looking at the sun, it doesn't

Andrew Huberman (1:08:56.640)

matter. It's a photon counter. It's literally counting photons. And it's saying, Oh, even

Andrew Huberman (1:09:01.200)

though it's a cloudy day, lots of photons coming in at winter in Boston, it must be winter. And

Andrew Huberman (1:09:05.760)

your system is a little depressed. It's spring. You feel alert. That's not a coincidence. That's

Andrew Huberman (1:09:09.600)

these melanopsin cells signaling the circadian clock. There are a bunch of other neurons in the

Andrew Huberman (1:09:14.080)

eye that signal to the brain and they mainly signal the presence of things that are lighter

Andrew Huberman (1:09:20.320)

than background or darker than background. So a black objects would be darker than background,

Andrew Huberman (1:09:25.360)

a light object lighter than background. And that all come, it's mainly it's looking at pixels.

Lex Fridman (1:09:29.760)

Mainly it's they look at circles and those neurons have receptive fields,

Andrew Huberman (1:09:34.240)

which not everyone will understand, but those neurons respond best to little circles of dark

Andrew Huberman (1:09:38.640)

light or little circles of bright light, little circles of red light versus little circles of

Andrew Huberman (1:09:43.360)

green light or blue light. And so it sounds very basic. It's like red, green, blue and circles

Andrew Huberman (1:09:50.320)

brighter or dimmer than what's next to it. But that's basically the only information that sent

Andrew Huberman (1:09:55.920)

down the optic nerve. And when we say information, we can be very precise. I don't mean little bits

Andrew Huberman (1:10:01.040)

of red traveling down the optic nerve. I mean, spikes neural action potentials in space and time,

Andrew Huberman (1:10:06.800)

which for you is like makes total sense. But I think for a lot of people, it's actually beautiful

Andrew Huberman (1:10:12.480)

to think about all that information in the outside world is converted into a language

Andrew Huberman (1:10:17.280)

that's very simple. It's just like a few syllables, if you will. And those syllables

Andrew Huberman (1:10:21.520)

are being shouted down the optic nerve, converted into a totally different language, like Morse code

Andrew Huberman (1:10:28.320)

goes into the brain. And then the thalamus essentially responds in the same way that

Andrew Huberman (1:10:31.360)

the retina does, except the thalamus is also waiting things. It's saying, you know what,

Andrew Huberman (1:10:37.680)

that thing was moving faster than everything else, or it's brighter than everything else.

Lex Fridman (1:10:43.680)

So that signal I'm going to get up, I'm going to allow up to cortex or that signal is much

Andrew Huberman (1:10:50.400)

redder than it is green. So I'm going to let that signal go through that signal as much.

Andrew Huberman (1:10:54.880)

It's kind of more like the red next to it. Throw that out. The information just doesn't get up into

Andrew Huberman (1:10:59.840)

your cortex. And then in cortex, of course, is where perceptions happen. And in V1, if you will,

Andrew Huberman (1:11:04.560)

visual area one, but also some neighboring areas, you start getting representations of

Andrew Huberman (1:11:10.160)

things like oriented lines. So there's a neuron that responds to this angle of my hand versus

Andrew Huberman (1:11:15.520)

vertical. This is the defining work of Hubel and Wiesel's Nobel. And it's a very systematic map

Andrew Huberman (1:11:21.840)

of orientation, line orientation, direction of movement, and so forth. And that's pretty much,

Lex Fridman (1:11:28.480)

and color, and that's how the visual system is organized all the way up to the cortex.

Lex Fridman (1:11:32.080)

So it's hierarchical. I want to be clear. It's hierarchical because you don't build up that line

Andrew Huberman (1:11:37.920)

by suddenly having a neuron that responds to lines in some random way. It responds to lines

Andrew Huberman (1:11:43.280)

by taking all the dots that are aligned in a vertical stack, and they all converge on one

Andrew Huberman (1:11:48.160)

neuron. And then that neuron responds to vertical lines. So it's not random. There's no abstraction

Andrew Huberman (1:11:53.920)

at that point, in fact. In fact, if I showed you a black line, I could be sure that if I

Andrew Huberman (1:11:58.960)

were imaging V1, that I would see a representation of that black line as a vertical line somewhere in

Andrew Huberman (1:12:04.880)

your cortex. So at that point, it's absolutely concrete. It's not abstract. But then things get

Andrew Huberman (1:12:12.400)

really mysterious. Some of that information travels further up into the cortex and goes from

Andrew Huberman (1:12:18.320)

one visual area to the next, to the next, to the next, so that by time you get into an area that

Andrew Huberman (1:12:23.360)

Nancy Kanwisher at MIT has studied much of her career, the fusiform face area, you start finding

Andrew Huberman (1:12:30.560)

single neurons that respond only to your father's face or to Joe Rogan's face, regardless of the

Andrew Huberman (1:12:38.560)

orientation of his face. I'm sure if you saw Joe, because you know him well, from across the room

Lex Fridman (1:12:43.760)

and you just saw his profile, you'd be like, oh, that's Joe. Walk over and say hello.

Andrew Huberman (1:12:48.960)

The orientation of his face isn't there. You wouldn't even see his eyes necessarily,

Lex Fridman (1:12:52.640)

but he's represented in some abstract way by a neuron that actually would be called the Joe

Andrew Huberman (1:12:57.920)

Rogan neuron. He might have limits. I might not recognize him if he was upside down or

Andrew Huberman (1:13:03.360)

something like that. It'd be fascinating to see what the limits of that Joe Rogan concept is.

Lex Fridman (1:13:08.160)

So Nancy's lab has done that because early on she was challenged by people that said

Andrew Huberman (1:13:12.400)

there aren't face neurons. There are neurons that they only respond to space and time,

Andrew Huberman (1:13:17.680)

shapes and things like that, moving in particular directions and orientations. It turns out

Andrew Huberman (1:13:22.240)

Nancy was right. They use these stimuli called greeble stimuli, which any computer programmer

Andrew Huberman (1:13:27.920)

would appreciate, which kind of morphs a face into something gradually that eventually just

Andrew Huberman (1:13:32.080)

looks like this alien thing they call the greeble. The neurons don't respond to greebles.

Andrew Huberman (1:13:37.600)

In most cases, they only respond to faces and familiar faces. Anyway, I'm summarizing a lot

Andrew Huberman (1:13:42.400)

of literature and forgive me, Nancy, and for those of the greeble people, if they're ours,

Andrew Huberman (1:13:46.000)

they're like, don't come after me with pitchforks. Actually, you know what? Come after me with

Andrew Huberman (1:13:49.760)

pitchforks. I think you know what I'm trying to do here. So the point is that in the visual system,

Andrew Huberman (1:13:54.480)

it's very concrete up until about visual area four, which has color pinwheels and seems to

Andrew Huberman (1:14:00.640)

respond to pinwheels of colors. And so the stimuli become more and more elaborate, but at some point

Andrew Huberman (1:14:07.360)

you depart that concrete representation and you start getting abstract representations that can't

Andrew Huberman (1:14:12.480)

be explained by simple point to point wiring. And to take a leap out of the visual system to

Andrew Huberman (1:14:18.400)

the higher level concepts, what we talked about in the visual system maps to the auditory system

Andrew Huberman (1:14:23.840)

where you're encoding what? Frequency of tone sweeps. So this is going to sound weird to do,

Lex Fridman (1:14:29.440)

but you know, like a Doppler, like hearing something, a car passing by, for instance,

Lex Fridman (1:14:34.480)

but at some point you get into motifs of music that can't be mapped to just a, what they call a

Andrew Huberman (1:14:41.440)

tonotopic map of frequency. You start abstracting. And if you start thinking about concepts of

Andrew Huberman (1:14:47.200)

creativity and love and memory, like what is the map of memory space? Well, your memories are very

Andrew Huberman (1:14:54.880)

different than mine, but presumably there's enough structure at the early stages of memory processing

Andrew Huberman (1:15:00.240)

or at the early stages of emotional processing or at the earlier stages of creative processing

Lex Fridman (1:15:06.480)

that you have the building blocks, your zeros and ones, if you will,

Lex Fridman (1:15:10.880)

but you depart from that eventually. Now the exception to this, and I want to be really clear

Andrew Huberman (1:15:16.960)

because I was just mainly talking about neocortex, the six layered structure on the outside of the

Andrew Huberman (1:15:22.080)

brain that explains a lot of human abilities, other animals have them too, is that subcortical

Andrew Huberman (1:15:28.480)

structures are a lot more like machines. It's more plug and chug. And what I'm talking about

Andrew Huberman (1:15:35.280)

is the machinery that controls heart rate and breathing and receptive fields, neurons that

Andrew Huberman (1:15:41.360)

respond to things like temperature on the top of my left hand. I came into neuroscience from

Andrew Huberman (1:15:48.560)

more of a perspective initially of psychology, but one of the reasons I forced upon myself to learn

Andrew Huberman (1:15:54.960)

some electrophysiology, not a ton, but enough, and some molecular biology and about circuitry

Andrew Huberman (1:16:00.560)

is that one of the most beautiful experiences you can have in life, I'm convinced, is to lower

Andrew Huberman (1:16:06.240)

an electrode into the cortex and to show a person or an animal, we do this ethically of course,

Andrew Huberman (1:16:14.800)

stimulus like an oriented line or a face. And you can convert the recordings coming off of

Andrew Huberman (1:16:20.560)

that electrode into an audio signal or an audio monitor, and you can hear what they call hash.

Andrew Huberman (1:16:25.360)

It's not the hash you smoke, it's the hash you hear. And it sounds like, it just sounds like

Andrew Huberman (1:16:31.760)

noise. And in the cortex, eventually you find a stimulus that gets the neuron to spike and

Andrew Huberman (1:16:37.760)

fire action potentials that are converted into an auditory stimulus that are very concrete,

Andrew Huberman (1:16:41.920)

crack, crack, crack, sounds like a bat cracking, like home runs or outfield balls.

Andrew Huberman (1:16:49.200)

When you drop electrodes deeper into the thalamus or into the hypothalamus or into the brainstem

Andrew Huberman (1:16:55.680)

areas that control breathing, it's like a machine. You never hear hash. You drop the electrode down.

Andrew Huberman (1:17:00.800)

This could be like a grungy old Tugston electrode, not high fidelity electrode, as long as it's got

Andrew Huberman (1:17:07.600)

a little bit of insulation on it. You plug it into an audio monitor, it's picking up electricity.

Lex Fridman (1:17:11.440)

And if it's a visual neuron and it's in the thalamus or the retina and you walk in front

Andrew Huberman (1:17:16.000)

of that animal or person, that neuron goes, and then you walk away and it stops. And you put your

Andrew Huberman (1:17:23.360)

hand in front of the eye again and it goes, and you could do that for two days. And that neuron

Andrew Huberman (1:17:30.320)

will just, every time there's a stimulus, it fires. So whereas before, it's a question of

Lex Fridman (1:17:34.560)

how much information is getting up to cortex. And then these abstractions happening where

Lex Fridman (1:17:38.720)

you're creating these ideas, when you go subcortical, everything is.

Andrew Huberman (1:17:44.560)

There's no abstraction.

Andrew Huberman (1:17:45.440)

It's two plus two equals four. There's no abstractions. And this is why I know we have

Andrew Huberman (1:17:50.320)

some common friends at Neuralink and I love the demonstration they did recently. I'm a huge fan

Andrew Huberman (1:17:54.640)

of what they're doing and where they're headed. And no, I don't get paid to say that. And I have

Andrew Huberman (1:17:59.120)

no business relationship to them. I'm just a huge fan of the people in the mission.

Lex Fridman (1:18:03.440)

But my question was to some of them, when are you going to go subcortical? Because if you want to

Andrew Huberman (1:18:09.120)

control an animal, you don't do it in the cortex. The cortex is like the abstract painting I made

Andrew Huberman (1:18:14.720)

of your face. Removing one piece or changing something may or may not matter for the abstraction.

Lex Fridman (1:18:21.120)

But when you are in the subcortical areas of the brain, a stimulating electrode can

Andrew Huberman (1:18:26.000)

evoke an entire behavior or an entire state. And so the brain, if we're going to have a

Andrew Huberman (1:18:31.040)

discussion about the brain and how the brain works, we need to really be clear which brain,

Andrew Huberman (1:18:36.560)

because everyone loves neocortex. It's like, oh, canonical circuits in cortex. We're going to get

Andrew Huberman (1:18:41.360)

the cortical connectome. And sure, necessary, but not sufficient. Not to be able to plug in

Andrew Huberman (1:18:47.840)

patterns of electrical stimulation and get behavior. Eventually we'll get there. But if

Andrew Huberman (1:18:51.840)

you're talking subcortical circuits, that's where the action is. That's where you could potentially

Andrew Huberman (1:18:56.400)

cure Parkinson's by stimulating the subthalamic nucleus, because we know that it gates motor

Andrew Huberman (1:19:01.600)

activation patterns in very predictable ways. So I think for those that are interested in

Andrew Huberman (1:19:06.320)

neuroscience, it pays to pay attention to like, is this a circuit that abstracts the sensory

Lex Fridman (1:19:11.840)

information? Or is it just one that builds up hierarchical models in a very predictable way?

Lex Fridman (1:19:18.160)

And there's a huge chasm in neuroscience right now, because there's no conceptual

Andrew Huberman (1:19:23.280)

leadership. No one knows which way to go. And this is why I think Neuralink has captured an

Andrew Huberman (1:19:28.000)

amazing opportunity, which was, okay, well, while all you academic research labs are figuring all

Andrew Huberman (1:19:32.320)

this stuff out, we're going to pick a very specific goal and make the goal, the end point. And some

Andrew Huberman (1:19:37.120)

academic laboratories do that, but I think that's a beautiful way to attack this whole thing about

Andrew Huberman (1:19:42.960)

the brain, because it's very concrete. Let's restore motion to the Parkinsonian patient.

Andrew Huberman (1:19:48.480)

Academic labs want to do that too, of course. Let's restore speech to the stroke patient.

Lex Fridman (1:19:54.960)

But there's nothing abstract about that. That's about figuring out the solution to a particular

Andrew Huberman (1:19:59.680)

problem. So anyway, those are my... And I admit I've mixed in a lot of opinion there,

Lex Fridman (1:20:04.560)

but having spent some time, like 25 years digging around in the brain and listening to neurons

Andrew Huberman (1:20:09.120)

firing and looking at them anatomically, I think given it's 2020, we need to ask the right... The

Andrew Huberman (1:20:15.680)

way to get better answers is ask better questions. And the really high level stuff is fun. It makes

Andrew Huberman (1:20:22.080)

for good conversation and it has brought enormous interest. But I think the questions about

Andrew Huberman (1:20:28.800)

consciousness and dreaming and stuff, they're fascinating, but I don't know that we're there yet.

Lex Fridman (1:20:34.240)

So you're saying there might be a chasm in the two views of the power of the brain arising from

Andrew Huberman (1:20:46.880)

the circuitry that forms abstractions or the power of the brain arising from the majority

Andrew Huberman (1:20:53.440)

of the circuitry that's just doing very brute force, dumb things that don't have any fancy

Andrew Huberman (1:21:02.000)

kind of stuff going on. That's really interesting to think about.

Lex Fridman (1:21:05.680)

And which one to go after first. And here I'm poaching badly from someone I've never met,

Lex Fridman (1:21:11.440)

but whose work I follow, which is, and it was actually on your podcast. I think Elon Musk

Andrew Huberman (1:21:16.320)

said, basically the brain is a, I want to say a monkey brain with a supercomputer on top.

Lex Fridman (1:21:21.120)

And I thought that's actually probably the best description of the brain I've ever heard because

Andrew Huberman (1:21:25.120)

it captures a lot of important features like limbic friction. But we think of like, oh,

Andrew Huberman (1:21:30.560)

when we're making plans, we're using the prefrontal cortex and we're executive function

Lex Fridman (1:21:34.640)

and all this kind of stuff. But think about the drug addict who's driven to go pursue

Andrew Huberman (1:21:40.240)

heroin or cocaine. They make plans. So clearly they use their frontal cortex. It's just that

Andrew Huberman (1:21:45.040)

it's been hijacked by the limbic system and all the monkey brain as he referred to. It's really

Andrew Huberman (1:21:49.680)

not fair to monkeys though, Elon, because actually monkeys can make plans. They just don't make plans

Andrew Huberman (1:21:53.840)

as sophisticated as us. I've spent a lot of time with monkeys, but I've also spent a lot of time

Andrew Huberman (1:21:57.280)

with humans. Anyway, you're saying like, there's a lot of value to focusing on the monkey brain

Andrew Huberman (1:22:02.880)

or whatever the heck you call it. I do because let's say I had an ability to place a chip anywhere

Andrew Huberman (1:22:08.640)

I wanted in the brain today and activate it or inhibit that area. I'm not sure I would put that

Andrew Huberman (1:22:14.400)

chip in neocortex, except maybe to just kind of have some fun and see what happens. The reason

Andrew Huberman (1:22:19.440)

is it's an abstraction machine. And especially if I wanted to make a mass production tool,

Andrew Huberman (1:22:24.000)

a tool in mass production that I could give to a lot of people, because it's quite possible that

Andrew Huberman (1:22:28.560)

your abstractions are different enough than mine that I wouldn't know what patterns of firing to

Andrew Huberman (1:22:33.440)

induce. But if I want, let's say I want to increase my level of focus and creativity. Well, then I

Andrew Huberman (1:22:40.320)

would love to be able to, for instance, control my level of limbic friction. I would love to be

Andrew Huberman (1:22:45.600)

able to wake up and go, Oh, you know what? I have an eight o clock appointment. I wake up slowly.

Lex Fridman (1:22:49.280)

So between seven, eight, but I want to do a lot of linear thinking. So you know what? I'm going to

Andrew Huberman (1:22:52.560)

just, I'm going to turn down the limbic friction and or ramp up prefrontal cortexes activation.

Lex Fridman (1:23:00.160)

So there's a lot of stuff that can happen in the thalamus with sensory gating. For instance,

Andrew Huberman (1:23:04.960)

you could shut down that shell around the thalamus and allow more creative thinking by allowing more

Andrew Huberman (1:23:09.920)

lateral connections. These would be some of the, those would be the experiments I'd want to do.

Lex Fridman (1:23:13.920)

So they're in the subcortical quote unquote monkey brain, but you could then look at what sorts of

Andrew Huberman (1:23:19.280)

abstract thoughts and behaviors would arise from that rather than, and here I'm not pointing my

Andrew Huberman (1:23:26.000)

finger at neural link at all, but there's this obsession with neocortex, but I, I'm going to,

Andrew Huberman (1:23:31.680)

well, I might lose a few friends, but I'll hopefully gain a few. And also one of the

Andrew Huberman (1:23:36.640)

reasons people spend so much time in neocortex. Yes. I have a fact and an opinion. One fact is

Andrew Huberman (1:23:42.960)

that you can image there and you can record there right now, the two photon and one photon microscopy

Andrew Huberman (1:23:49.120)

methods that allow you to image deep into the brain still don't allow you to image down really

Andrew Huberman (1:23:53.600)

deep unless you're jamming prisms in there and endoscopes. And then the endoscopes are very

Andrew Huberman (1:23:57.840)

narrow. So you're getting very, you know, it's like looking at the bottom of the ocean through a,

Andrew Huberman (1:24:02.000)

through a spotlight. And so you much easier look at the waves up on top. Right. So let's face it,

Andrew Huberman (1:24:07.840)

folks. A lot of the reasons why there's so many recordings in layer two, three of cortex with all

Andrew Huberman (1:24:12.000)

this advanced microscopy is because it's very hard to image deeper. Now the microscopes are getting

Andrew Huberman (1:24:17.280)

better and thanks to the amazing work, mainly of engineers and chemists and physicists. Let's face

Andrew Huberman (1:24:22.640)

it. They're the ones who brought this revolution to neuroscience in the last 10 years or so.

Andrew Huberman (1:24:27.040)

You can image deeper, but we don't really, that's why you see so many reports on layer two, three.

Andrew Huberman (1:24:33.280)

The other thing, which is purely opinion, and I'm not going after anybody here, but is that

Andrew Huberman (1:24:38.160)

as long as there's no clear right answer, it becomes a little easier to do creative work

Andrew Huberman (1:24:43.760)

in a structure where no one really knows how it works. So it's fun to probe around because anything

Andrew Huberman (1:24:48.640)

you see is novel. If you're going to work in the thalamus or the pulvinar or the hypothalamus or

Andrew Huberman (1:24:54.400)

these structures that have been known about since the sixties and seventies, and really since the,

Andrew Huberman (1:24:58.160)

you know, centuries ago, you are dealing with existing, you have to combat existing models.

Lex Fridman (1:25:04.720)

And whereas in cortex, no one knows how the thing works, the neocortex, six layer cortex.

Lex Fridman (1:25:10.240)

And so there's a lot more room for discovery. There's a lot more room for discovery and I'm

Andrew Huberman (1:25:14.720)

not calling anyone out. I love cortex. We've published some papers on cortex. It's super

Andrew Huberman (1:25:18.240)

interesting. But I think with the tools that are available nowadays and where people are trying

Andrew Huberman (1:25:24.560)

ahead of, of not just reading from the brain, monitoring activity, but writing to the brain,

Lex Fridman (1:25:29.040)

I think we really have to be careful and we need to be thoughtful about what are we trying to write?

Lex Fridman (1:25:34.720)

What script are we trying to write? Because there are many brain structures for which we already

Andrew Huberman (1:25:38.400)

know what scripts they write. And I think there's tremendous value there. I don't think it's boring.

Andrew Huberman (1:25:42.960)

The fact that they act like machines makes them predictable. Those are your zeros and ones.

Andrew Huberman (1:25:47.680)

Let's start there. But let the, what they're, what's sort of happening in this field of writing

Andrew Huberman (1:25:52.080)

to the brain is there's this idea. And again, I want to be clear. I'm not pointing at Neuralink.

Andrew Huberman (1:25:56.000)

I'm mainly pointing at the neocortical jockeys out there that you go and you observe patterns.

Lex Fridman (1:26:02.880)

And then you think replaying those patterns is going to give rise to something interesting.

Andrew Huberman (1:26:06.880)

Yeah. I should call out one experiment or two experiments, which were done by Susumu

Andrew Huberman (1:26:11.280)

Tonagawa, Nobel prize winner from MIT, done important work in memory and immunology,

Andrew Huberman (1:26:16.720)

of course, is where he got his Nobel as well as Mark Mayford's lab at UC San Diego.

Andrew Huberman (1:26:21.680)

They did an experiment where they monitored a bunch of neurons while an animal learned something.

Andrew Huberman (1:26:26.560)

Then they captured those neurons through some molecular tricks so they could replay the neurons.

Lex Fridman (1:26:32.080)

So now there's like perfect case scenario. It's like, okay,

Andrew Huberman (1:26:35.200)

you monitor the neurons in your brain. Then I say, okay, neurons one through 100 were played

Andrew Huberman (1:26:40.080)

in the particular sequence. So, you know, the space time, you know, the keys on the piano that

Andrew Huberman (1:26:43.440)

were played that gave rise to the song, which was the behavior. And then you go back and you

Andrew Huberman (1:26:47.600)

reactivate those neurons, except you reactivate them all at once, like slamming on all the keys

Lex Fridman (1:26:52.800)

once on the piano and you get the exact same behavior. So the space time code

Andrew Huberman (1:27:00.320)

may be meaningless for some structures. Now that's freaky. That's a scary thing because what that

Andrew Huberman (1:27:07.760)

means is that all the space time firing in cortex, the space part may matter more than the time part.

Andrew Huberman (1:27:16.000)

So, you know, rate codes and space time codes, we don't know. And, you know, I'd rather have,

Andrew Huberman (1:27:21.920)

I'd rather deliver more answers in this discussion questions, but I think it's an important

Andrew Huberman (1:27:25.840)

consideration. You're saying some of the magic is in the early stages of what the closer to the

Andrew Huberman (1:27:31.760)

raw information. I believe so. You know, the stimulus, you know, the neuron that encodes

Andrew Huberman (1:27:38.080)

that stimulus. So, you know, the transformation. When I say this for those who don't think about

Andrew Huberman (1:27:42.640)

sensory transformations, it's like, I can show you a red circle. And then I look at how many times

Andrew Huberman (1:27:48.960)

the neuron fires in response to that red circle. And then I could show the red circle a bunch of

Andrew Huberman (1:27:52.880)

times, green circle, see if it changes. And then essentially the number of times that is the

Andrew Huberman (1:27:56.800)

transformation. You've converted red circle into like three action potentials, you know, beep, beep,

Andrew Huberman (1:28:02.240)

beep, or whatever you want to call it, you know, for those that think in sound space.

Lex Fridman (1:28:05.120)

So that's what you've created, you know, the transformation and you march up the,

Andrew Huberman (1:28:09.680)

it's called the neuro axis as you go from the periphery up into the cortex. And we know that,

Lex Fridman (1:28:16.640)

and I know Lisa Feldman Barrett, or is it Barrett Feldman? Barrett Feldman, excuse me,

Andrew Huberman (1:28:25.280)

Lisa, that talked a lot about this, that, you know, birds can do sophisticated things and whatnot as

Andrew Huberman (1:28:30.080)

well, but humans, there's a strong, what we call cephalization. A lot of the processing

Andrew Huberman (1:28:35.120)

has moved up into the cortex and out of these subcortical areas, but it happens nonetheless.

Lex Fridman (1:28:39.920)

And so as long as you know the transformations, you are in a perfect place to build machines

Andrew Huberman (1:28:44.640)

or add machines to the brain that exactly mimic what the brain wants to do, which is take events

Andrew Huberman (1:28:51.120)

in the environment and turn them into internal firing of neurons.

Lex Fridman (1:28:55.200)

So the mastery of the brain can happen at their early level. You know, another perspective of it

Andrew Huberman (1:28:59.440)

is you saying this means that humans aren't that special. If we look at the evolutionary time scale,

Andrew Huberman (1:29:07.200)

the leap to intelligence is not that special. So like the extra layers of abstraction

Andrew Huberman (1:29:12.480)

isn't where most of the magic happens of intelligence, which gives me hope that maybe,

Andrew Huberman (1:29:18.000)

if that's true, that means the evolution of intelligence is not that rare of an event.

Andrew Huberman (1:29:23.440)

I certainly hope not.

Lex Fridman (1:29:24.640)

Oh, so you hope there's...

Andrew Huberman (1:29:27.200)

I hope there are other forms of intelligence. I mean, I think what humans are really good at,

Lex Fridman (1:29:32.880)

and here I want to be clear that this is not a formal model, but what humans are really good at

Andrew Huberman (1:29:38.240)

is taking that plasma barbell that we were talking about earlier and not just using it for analysis

Andrew Huberman (1:29:45.040)

of space, like the intermediate environment, but also using historical information. Like I can read

Andrew Huberman (1:29:50.400)

a book today about the history of medicine. I happen to be doing that lately for some stuff

Andrew Huberman (1:29:54.240)

I'm researching and I can take that information and if I want, I can inject it into my plans for

Andrew Huberman (1:29:58.560)

the future. Other animals don't seem to do that over the same time scales that we do. Now,

Andrew Huberman (1:30:06.080)

it may be that the chipmunks are all hiding little notebooks everywhere in the form of little dirt

Andrew Huberman (1:30:11.520)

castles or something that we don't understand. I mean, the waggle dance of the bee is in the most

Andrew Huberman (1:30:15.600)

famous example. Bees come back to the hive, they orient relative to the honeycomb and they waggle.

Andrew Huberman (1:30:21.600)

There's a guy down in Australia named Serena Vasson who studied this. It's really interesting.

Andrew Huberman (1:30:25.840)

No one really understands it except he understands it best. The bee waggles in a couple of ways

Andrew Huberman (1:30:32.400)

relative to the orientation of the honeycomb and then all the other bees see that it's visual and

Andrew Huberman (1:30:38.000)

they go out and they know the exact coordinate system to get to the source of whatever it was,

Andrew Huberman (1:30:43.440)

the food and bring it back. He's done it where they isolate the bees, he's changed the visual

Andrew Huberman (1:30:47.760)

flight environment, all this stuff. They are communicating and they're communicating something

Andrew Huberman (1:30:52.240)

about something they saw recently, but it doesn't extend over very long periods of time.

Andrew Huberman (1:30:57.760)

The same way that you and I can both read a book or you can recommend something to me and then we

Andrew Huberman (1:31:02.000)

could converge on a set of ideas later. And in fairness, because she was the one that said it

Lex Fridman (1:31:07.680)

and I didn't and I hadn't even thought of it, when you talk to Lisa on your podcast,

Andrew Huberman (1:31:12.560)

she brought up something beautiful, which is that it never really occurred to me and I was

Andrew Huberman (1:31:18.320)

sort of embarrassed that it hadn't, but it's really beautiful and brilliant, which is that

Andrew Huberman (1:31:23.760)

we don't just encode senses in the form of like color and light and sound waves and taste,

Lex Fridman (1:31:28.400)

but ideas become a form of sensory mapping. And that's where the really, really cool and

Andrew Huberman (1:31:35.120)

exciting stuff is, but we just don't understand what the receptive fields are for ideas. What's

Lex Fridman (1:31:38.880)

an idea receptive field? And how they're communicated

Andrew Huberman (1:31:43.840)

between humans because we seem to be able to encode those ideas in some kind of way.

Andrew Huberman (1:31:49.280)

You'd be able to encode those ideas in some kind of way. Yes, it's taking all the raw information

Lex Fridman (1:31:54.320)

and the internal physical states, that sensory information put into this concept blob that we

Andrew Huberman (1:32:01.040)

cut in the store and then we're able to communicate that. Yeah, your abstractions are different than

Andrew Huberman (1:32:04.880)

mine. I actually think the comment section on social media is a beautiful example of where

Andrew Huberman (1:32:10.880)

the abstractions are different for different people. So much of the misunderstanding of the

Andrew Huberman (1:32:15.680)

world is because of these idea receptive fields, they're not the same. Whereas I can look at a

Andrew Huberman (1:32:22.400)

photoreceptor neuron or olfactory neuron or a V1 neuron, and I am certain, I would bet my life

Andrew Huberman (1:32:28.320)

that yours look and respond exactly the same way that Lisa's do and mine do. But once you get

Andrew Huberman (1:32:34.640)

beyond there, it gets tricky. And so when you say something or I say something and somebody gets

Andrew Huberman (1:32:39.680)

upset about it or even happy about it, their concept of that might be quite a bit different.

Lex Fridman (1:32:45.520)

They don't really know what you mean. They only know what it means to them.

Andrew Huberman (1:32:50.560)

Yeah. So from a neural link perspective, it makes sense to optimize the control and the

Andrew Huberman (1:32:55.040)

augmentation of the more primitive circuitry. So like the stuff that is closer to the raw sensory

Andrew Huberman (1:33:03.040)

information. Go deeper. If they, I think, go deeper into the brain. And to be fair,

Lex Fridman (1:33:08.160)

so Matt McDougall, who's a neurosurgeon at Neuralink and also a clinical nurse, a great guy,

Andrew Huberman (1:33:13.680)

brilliant. They have amazing people. I have to give it to them. They've been very cryptic in

Andrew Huberman (1:33:18.000)

recent years. Their website was just like nothing there. They really know how to do things with

Andrew Huberman (1:33:23.920)

style. And they've upset a lot of people, but that's good too. But Matt is there. I know Matt,

Andrew Huberman (1:33:30.320)

he actually came up through my lab at Stanford, although he was a neurosurgery resume. He spent

Andrew Huberman (1:33:34.080)

time in our lab. He actually came out on the shark dive and did great white shark diving with my lab

Andrew Huberman (1:33:38.480)

to collect the VR that we use in our fear stuff. I've talked to Matt and I think he and other folks

Andrew Huberman (1:33:44.240)

there are hungry for the deeper brain structures. The problem is that damn vasculature, all that

Andrew Huberman (1:33:49.760)

blood supply. It's not trivial to get through and down into the brain without damaging the

Andrew Huberman (1:33:56.080)

vasculature in the neocortex, which is on the outer crust. But once you start getting into

Andrew Huberman (1:33:59.920)

the thalamus and closer to some of the main arterial sources, you really risk getting massive

Andrew Huberman (1:34:04.960)

bleeds. And so it's an issue that can be worked out. It just is hard. Maybe it'd be nice to educate.

Andrew Huberman (1:34:12.560)

I'm sure my ignorance. So the smart stuff is on the surface. So I didn't realize this. I didn't

Andrew Huberman (1:34:19.600)

quite realize because you keep saying deep. Yeah. So like the early stages are deep.

Andrew Huberman (1:34:26.160)

Yeah. So in actual, physically in the brain. Yeah. So the way that, of course you got your

Andrew Huberman (1:34:33.360)

deep brain structures, they're involved in breathing and heart rate and kind of lizard

Andrew Huberman (1:34:36.560)

brain stuff. And then on top of that, this is the model of the brain that no one really subscribes

Andrew Huberman (1:34:42.480)

to anymore, but anatomically it works. And then on top in mammals. And then on top of that,

Andrew Huberman (1:34:46.720)

you have the limbic structures, which gate sensory information and decide whether or not

Andrew Huberman (1:34:50.800)

you're going to listen to something more than you're going to look at it, or you're going to

Andrew Huberman (1:34:53.280)

split your attention to both kind of sensory allocation stuff. And then the neocortex is on

Andrew Huberman (1:34:59.840)

the outside. And that is where you get a lot of this abstraction stuff. And now not all cortical

Andrew Huberman (1:35:06.560)

areas are doing abstraction. Some like visual area one, auditory area one, they're just doing

Andrew Huberman (1:35:11.600)

concrete representations. But as you get into the higher order stuff, that when you start hearing

Andrew Huberman (1:35:17.840)

names like inferoparietal cortex, and when you start hearing multiple names in the same, then

Andrew Huberman (1:35:22.720)

you're talking about higher order areas. But actually there's an important experiment that

Andrew Huberman (1:35:28.800)

drives a lot of what people want to do with brain machine interface. And that's the work of Bill

Andrew Huberman (1:35:33.440)

Newsome, who is at Stanford and Tony Movshin, who runs the Center for Neuroscience at NYU.

Andrew Huberman (1:35:38.000)

This is a wild experiment. And I think it might freak a few people out if they really think about

Andrew Huberman (1:35:42.800)

it too deeply. But anyway, here it goes. There's an area called MT in the cortex. And if I showed

Andrew Huberman (1:35:50.800)

you a bunch of dots all moving up, and this is what Tony and Bill and some of the other people

Andrew Huberman (1:35:57.120)

in that lab did way back when, is they show a bunch of dots moving up. Somewhere in MT,

Andrew Huberman (1:36:02.160)

there's some neurons that respond. They fire when the neurons move up. And then what they did is

Andrew Huberman (1:36:06.560)

they started varying the coherence of that motion. So they made it so only 50% of the dots moved up

Lex Fridman (1:36:10.800)

and the rest move randomly. And that neuron fires a little less. And eventually it's random and that

Andrew Huberman (1:36:15.520)

neuron stops firing because it's just kind of dots moving everywhere. It's awesome. And there's a

Andrew Huberman (1:36:19.360)

systematic map so that other neurons are responding and things moving down and other things responding

Andrew Huberman (1:36:24.000)

left and other things moving right. Okay. So there's a map of direction space. Okay, well,

Andrew Huberman (1:36:29.360)

that's great. You could lesion MT, animals lose the ability to do these kind of coherence

Andrew Huberman (1:36:34.640)

discrimination or direction discrimination. But the amazing experiment, the one that just

Andrew Huberman (1:36:40.400)

is kind of eerie is that they lowered a stimulating electrode into MT, found a neuron

Andrew Huberman (1:36:46.480)

that responds to when dots go up, but then they silence that neuron. And sure enough,

Andrew Huberman (1:36:54.800)

the animal doesn't recognize the neurons are going up and then they move the dots down.

Andrew Huberman (1:37:01.680)

They stimulate the neuron that responds to things moving up and the animal responds because it can't

Andrew Huberman (1:37:08.960)

speak. It responds by doing a lever press, which says the dots are moving up. So in other words,

Andrew Huberman (1:37:13.440)

the sensory, the dots are moving down in reality on the computer screen. They're stimulating the

Andrew Huberman (1:37:19.440)

neuron that responds to dots moving up. And the perception of the animal is that dots are moving

Andrew Huberman (1:37:25.360)

up, which tells you that your perception of external reality absolutely has to be a neuronal

Andrew Huberman (1:37:32.560)

abstraction. It is not tacked to the movement of the dots in any absolute way. Your perception

Andrew Huberman (1:37:39.680)

of the outside world depends entirely on the activation patterns of neurons in the brain.

Lex Fridman (1:37:45.600)

And you can hear that and say, well, duh, because if I stimulate the stretch reflex and you kick or

Andrew Huberman (1:37:51.920)

something or whatever, the knee reflex and you kick, of course, there's a neuron that triggers

Andrew Huberman (1:37:55.760)

that, but it didn't have to be that way. Because A, the animal had prior experience, B, you're way

Andrew Huberman (1:38:01.520)

up in the higher order cortical areas. What this means is that, and I generally try and avoid

Andrew Huberman (1:38:08.880)

conversations about this kind of thing, but what this means is that we are constructing our reality

Andrew Huberman (1:38:14.960)

with this space time firing the zeros and ones. And it doesn't have to have anything to do with

Andrew Huberman (1:38:20.400)

the actual reality. And the animal or person can be absolutely convinced that that's what's

Andrew Huberman (1:38:25.920)

happening. Are you familiar with the work of Donald Hoffman? So he makes an evolutionary argument

Andrew Huberman (1:38:35.040)

that's not important of that. We, our brains are completely detached from reality in the sense that

Andrew Huberman (1:38:47.600)

he makes a radical case that we have no idea what physical reality is. And in fact,

Andrew Huberman (1:38:54.000)

it's drastically different than what we think it is. So he goes, that's scary. So he doesn't say

Andrew Huberman (1:39:02.480)

like there's just, cause you're kind of implying there's a gap. There might be a gap with constructing

Andrew Huberman (1:39:08.640)

an illusion and then maybe using communication to maybe create a consistency that's sufficient for

Andrew Huberman (1:39:17.040)

human collaboration or whatever, or mammal, you know, just maybe even just life forms constructing

Andrew Huberman (1:39:23.360)

a consistent reality that's maybe detached. I mean, that's really cool that neurons are constructing

Andrew Huberman (1:39:28.480)

that, like that you can prove that this is when neuroscience at its best vision science. But he

Andrew Huberman (1:39:34.800)

says that like our brain is actually just lost its shit on the, on the, on the path of evolution to

Andrew Huberman (1:39:43.280)

where we're normal. We're just playing games with each other in constructing realities that allow

Andrew Huberman (1:39:49.200)

our survival. But it's, it's, it's completely detached from physical reality. We're missing a

Andrew Huberman (1:39:54.880)

lot. We're missing like most of it, if not all of it. Well, this was, it's, it's fascinating because

Andrew Huberman (1:40:04.240)

I just saw the Oliver Sacks documentary. There's a new documentary out about his life. And there's

Andrew Huberman (1:40:09.520)

this one part where he's like, I've spent part of my life trying to imagine what it would like to be,

Andrew Huberman (1:40:14.160)

be, to be a bat or something, to see the world through the life, the sensory apparatus of a bat.

Lex Fridman (1:40:21.840)

And he did this with his, these patients that were locked into these horrible syndromes that

Andrew Huberman (1:40:26.240)

to pull out some of the, the beauty of their experience as well, not just communicate the

Andrew Huberman (1:40:31.040)

suffering, although the suffering too. And as I was listening to him talk about this,

Andrew Huberman (1:40:35.520)

I started to realize it's like, well, what, you know, like they're these mantis shrimps that can

Andrew Huberman (1:40:40.000)

see 60 shades of pink or something. And they, they see this stuff all the time and animals,

Andrew Huberman (1:40:44.800)

they can see UV light. Every time I learn about an animal that can sense other things in the

Andrew Huberman (1:40:50.400)

environment that I can't like heat sensing, well, not, I don't crave that experience the same way

Andrew Huberman (1:40:55.600)

Sacks talked about craving that experience, but it does throw another penny in the jar for what

Andrew Huberman (1:41:00.880)

you're saying, which is that it could be that most, if not all of what I perceive and believe

Andrew Huberman (1:41:07.120)

is just a neural fabrication and that for better, for worse, we all agree on enough

Andrew Huberman (1:41:14.400)

of the same neural fabrications in the same time and place that we're able to function.

Lex Fridman (1:41:18.560)

Not only that, but we agree with the things that are trying to eat us

Andrew Huberman (1:41:23.360)

enough to where we don't, they don't eat us. Meaning like that it's not just us humans,

Lex Fridman (1:41:30.000)

you know, right?

Andrew Huberman (1:41:30.560)

I see. Because it's interactive.

Andrew Huberman (1:41:32.000)

It's interactive. So like, so like now I think it's a really nice thought experiment.

Andrew Huberman (1:41:40.560)

I think because Donald really frames it in a scientific, like he makes a hard,

Andrew Huberman (1:41:47.600)

like as hard as our discussion has been now, he makes a hard scientific case that

Andrew Huberman (1:41:53.040)

we don't know shit about reality. I think that's a little bit hardcore, but I think it's,

Andrew Huberman (1:42:00.800)

I think it's hardcore, but I think it's a good thought experiment that kind of cleanses the

Andrew Huberman (1:42:06.400)

palette of the confidence we might have about, because we are operating in this abstraction

Andrew Huberman (1:42:13.840)

space, you know, and, you know, the sensory space, it might be something very different.

Lex Fridman (1:42:21.520)

And it's kind of interesting to think about if you start to go into the realm of Neuralink or

Andrew Huberman (1:42:27.040)

start to talk about just everything that you've been talking about with dream states and

Andrew Huberman (1:42:31.200)

psychedelics and stuff like that, which part of the, which layer can we control and play

Lex Fridman (1:42:36.960)

around with to maybe look into a different slice of reality?

Andrew Huberman (1:42:40.640)

I just got to do the experiment. The key is to just do the experiment in the most ethical way

Andrew Huberman (1:42:47.120)

possible. You just, I mean, that's the beauty of experiments. This is why, you know, there's

Andrew Huberman (1:42:53.360)

wonderful theoretical neuroscience happening now to make predictions. But that's why experimental

Andrew Huberman (1:42:59.280)

science is so wonderful. You can go into the laboratory and poke around in there and be a

Andrew Huberman (1:43:03.520)

brain explorer and listen to and write to neurons. And when you do that, you get answers. You don't

Andrew Huberman (1:43:09.600)

always get the answers you want, but that's, you know, that's the beauty of it. When you were

Andrew Huberman (1:43:14.480)

saying this thing about reality and the Donald Hoffman model, I was thinking about children,

Andrew Huberman (1:43:20.160)

you know, like when I have an older sister, she's very sane. But when she was a kid, she had an

Andrew Huberman (1:43:28.480)

imaginary friend and she would play with this imaginary friend. And it had, there was this

Andrew Huberman (1:43:33.360)

whole, there was a consistency. This friend was like, it was Larry lived in a purple house.

Andrew Huberman (1:43:37.520)

Larry was a girl. It was like all this stuff that a child, a young child wouldn't have any issue

Andrew Huberman (1:43:42.000)

with. And then one day she announced that Larry had died. Right. And it wasn't traumatic or

Andrew Huberman (1:43:46.160)

traumatic and that was it. And she just stopped. And I always wonder what that neuro developmental

Andrew Huberman (1:43:51.840)

event was that kept her out of a psychiatric ward had she kept that imaginary friend. But it's also,

Andrew Huberman (1:44:02.560)

there was something kind of sad to it. I think the way it was told to me, cause I'm the younger

Andrew Huberman (1:44:06.400)

brother, I didn't, I wasn't around for that. But my, my dad told me that, you know, there was a

Andrew Huberman (1:44:10.400)

kind of a sadness because it was this beautiful reality that had been constructed. And so we kind

Andrew Huberman (1:44:14.320)

of won. I wonder as you're telling me this, whether or not, you know, as adults, we try and

Andrew Huberman (1:44:19.600)

create as much reality for children as we can so that they can make predictions and feel safe

Andrew Huberman (1:44:24.080)

because the ability to make predictions is a lot of what keeps our autonomic arousal in check. I

Andrew Huberman (1:44:28.640)

mean, we go to sleep every night and we give up total control and that should frighten us deeply.

Lex Fridman (1:44:33.440)

But you know, unfortunately, autonomic arousal, the yanks us down under and we don't negotiate

Andrew Huberman (1:44:38.480)

too much. So you sleep sooner or later. I don't know. I was a little worried. We get into

Andrew Huberman (1:44:44.960)

discussions about the nature of reality because I'm I it's interesting in the laboratory. I'm a

Andrew Huberman (1:44:49.040)

very much like, what's the experiment? What would the, you know, what's the analysis going to look

Andrew Huberman (1:44:53.120)

like? What mutant mouse are we going to use? What, what, what experience are we going to put

Andrew Huberman (1:44:57.840)

someone through? But I think it's wonderful that in 2020, we can finally have discussions about

Andrew Huberman (1:45:02.880)

this stuff and look, kind of peek around the corner and say, well, Neuralink and people,

Andrew Huberman (1:45:08.720)

others who are doing similar things are going to figure it out. They're going to,

Lex Fridman (1:45:13.200)

the answers will show up and we just have to be open to interpretation.

Lex Fridman (1:45:17.440)

Do you think there could be an experiment centered around consciousness? I mean,

Andrew Huberman (1:45:21.920)

you're plugged into the neuroscience community. I think for the longest time, the quote unquote

Andrew Huberman (1:45:27.280)

C word was totally not, was almost anti scientific, but now more and more people are

Andrew Huberman (1:45:33.200)

talking about consciousness. Elon is talking about consciousness. AI folks are talking about

Andrew Huberman (1:45:38.320)

consciousness. It's, it's still nobody knows anything, but it feels like a legitimate domain

Andrew Huberman (1:45:46.400)

of inquiry. That's hungry for a real experiment. So I have fortunately three short answers to

Andrew Huberman (1:45:57.040)

this. The first one is, I'm not, I'm not particularly succinct. I agree that the joke

Andrew Huberman (1:46:05.600)

I always tell is there are two things you never want to say to a scientist. One is what do you

Andrew Huberman (1:46:10.720)

do? And the second one is take as much time as you need. And you definitely don't want to say

Andrew Huberman (1:46:14.720)

them in the same sentence. I have three short answers to it. So there's a, there's a cynical

Andrew Huberman (1:46:21.600)

answer kind of, and it's not one I enjoy giving, which is that if you look into the seventies and

Andrew Huberman (1:46:29.840)

eight back at the 1970s and 1980s, and even into the early two thousands, there were some very

Andrew Huberman (1:46:35.920)

dynamic, very impressive speakers who are very smart in the field of neuroscience and related

Andrew Huberman (1:46:42.640)

fields who thought hard about the consciousness problem and fell in love with the problem,

Lex Fridman (1:46:48.960)

but overlook the fact that the technology wasn't there. So I admire them for falling in love with

Andrew Huberman (1:46:58.200)

the problem, but they gleaned tremendous taxpayer resources essentially for nothing. And these

Andrew Huberman (1:47:06.440)

people know who they are. Some of them are alive. Some of them aren't. I'm not referring to Francis

Andrew Huberman (1:47:10.080)

Crick, who was brilliant by the way, and thought the claustrum was involved in consciousness,

Andrew Huberman (1:47:13.520)

which I think is a great idea. It's this obscure structure that no one's really studied. People

Andrew Huberman (1:47:17.680)

are now starting to study it. So I think Francis was brilliant and wonderful, but there it, you

Andrew Huberman (1:47:22.160)

know, there were books written about it. It makes for great television stuff and thought

Andrew Huberman (1:47:30.320)

around the table or after a couple of glasses of wine or whatever. It's an important problem

Andrew Huberman (1:47:35.760)

nonetheless. And so I think, I do think the consciousness, the issue is it's not operationally

Andrew Huberman (1:47:41.120)

defined, right? That psychologists are much smarter than a lot of hard scientists in that

Andrew Huberman (1:47:48.480)

for the following reason, they put operational definitions. They know that psychology, if we're

Andrew Huberman (1:47:54.080)

talking about motivation, for instance, they know they need to put operational definitions on that

Lex Fridman (1:47:58.000)

so that two laboratories can know they're studying the same thing. The problem with consciousness is

Andrew Huberman (1:48:02.400)

no one can agree on what that is. And this was a problem for attention when I was coming up. So in

Andrew Huberman (1:48:08.240)

the early two thousands, people would argue, what is attention? Is it spatial attention,

Andrew Huberman (1:48:11.680)

auditory attention? Is it, and finally people were like, you know what, we agree.

Lex Fridman (1:48:16.560)

Have they agreed on that one?

Lex Fridman (1:48:17.680)

Sort of.

Andrew Huberman (1:48:17.920)

I remember hearing people scream about attention.

Andrew Huberman (1:48:21.520)

Right. They couldn't even agree on attention. So I was coming up as a young graduate student,

Andrew Huberman (1:48:24.880)

I'm thinking like, I'm definitely not going to work on attention and I'm definitely not

Andrew Huberman (1:48:28.480)

going to work on consciousness. And I wanted something that I could solve or figure out.

Andrew Huberman (1:48:33.360)

I want to be able to see the circuit or the neurons. I want to be able to hear it on the

Andrew Huberman (1:48:37.520)

audio. I want to record from it. And then I want to do gain a function and loss a function,

Andrew Huberman (1:48:41.360)

take it away, see something change, put it back, see something change in a systematic way.

Lex Fridman (1:48:46.080)

And that takes you down into the depths of some stuff that's pretty plug and chug, you know,

Lex Fridman (1:48:51.840)

but you know, I'll borrow from something in the military because I'm fortunate to do some work

Andrew Huberman (1:48:56.240)

with units from special operations and they have beautiful language around things because their

Andrew Huberman (1:49:00.160)

world is not abstract. And they talk about three meter targets, 10 meter targets and 100 meter

Andrew Huberman (1:49:04.960)

targets. And it's not an issue of picking the 100 meter target because it's more beautiful

Andrew Huberman (1:49:09.200)

or because it's more interesting. If you don't take down the three meter targets and the 10

Andrew Huberman (1:49:12.960)

meter targets first, you're dead. So that's, I think scientists could pay to, you know, adopt

Andrew Huberman (1:49:19.840)

a more kind of military thinking in that, in that sense. The other thing that is really important is

Andrew Huberman (1:49:26.560)

that just because somebody conceived of something and can talk about it beautifully and can glean a

Andrew Huberman (1:49:30.880)

lot of resources for it, doesn't mean that it's led anywhere. So this isn't just true of the

Andrew Huberman (1:49:37.520)

consciousness issue. And I don't want to sound cynical, but I could pull up some names of

Andrew Huberman (1:49:41.200)

molecules that occupied hundreds of articles in the very premier journals that then were later

Andrew Huberman (1:49:47.920)

discovered to be totally moot for that process. And biotech companies folded everyone in the lab

Andrew Huberman (1:49:54.560)

pivots and starts doing something different with that molecule. And nobody talks about it because

Andrew Huberman (1:49:59.360)

as long as you're in the game, we have this thing called anonymous peer review. You can't afford to

Andrew Huberman (1:50:03.440)

piss off anybody too much, unless you have some other funding stream. And I have avoided battles

Andrew Huberman (1:50:09.360)

most of my career, but I pay attention to all of it. And I've watched this and I don't think it's

Andrew Huberman (1:50:14.480)

ego driven. I think it's that people fall in love with an idea. I don't think there's any,

Andrew Huberman (1:50:18.560)

there's not enough money in science for people to sit back there rubbing their hands together,

Andrew Huberman (1:50:22.240)

you know, the beauty of what Neuralink and Elon and team, cause obviously he's very impressive,

Lex Fridman (1:50:28.160)

but the team as a whole is really what gives me great confidence in their mission is that he's

Andrew Huberman (1:50:34.800)

already got enough money. So it can't be about that. He doesn't seem to need it at a level of,

Andrew Huberman (1:50:41.680)

I don't know him, but it doesn't, he doesn't seem to need it at a kind of an ego level or something.

Andrew Huberman (1:50:46.160)

I think it's driven by genuine curiosity and the team that he's assembled include people that are

Andrew Huberman (1:50:52.480)

very kind of abstract neuro neocortex, space time coding people. There are people like Matt,

Andrew Huberman (1:50:58.480)

who is a neurosurgeon. You can't, I mean, you know, you can't BS neurosurgery. Failures in

Andrew Huberman (1:51:05.360)

neurosurgery are not tolerated. So you have to be very good to exceptional to even get through the

Andrew Huberman (1:51:10.080)

gate. And he's exceptional. And then they've got people like Dan Adams, who was at UCSF for a long

Andrew Huberman (1:51:15.040)

time as a good friend and a known him for years, who is very concrete studied the vasculature in

Andrew Huberman (1:51:20.720)

the eye and how it maps to the vasculature and cortex. When you get a team like that together,

Andrew Huberman (1:51:25.120)

you're going to have dissenters. You're going to have people that are high level thinkers,

Andrew Huberman (1:51:29.440)

people that are coders. When you get a team like that, it no longer looks like an academic laboratory

Andrew Huberman (1:51:34.800)

or even a field in science. And so I think they're going to solve some really hard problems.

Lex Fridman (1:51:40.640)

And again, I'm not here. They don't, you know, I have nothing at stake with them, but I think

Andrew Huberman (1:51:47.680)

that's the solution. You need a bunch of people who don't need first author papers,

Andrew Huberman (1:51:52.320)

who don't need to complete their PhD, who aren't relying on outside funding, who have a clear

Andrew Huberman (1:51:56.640)

mission. And you have a bunch of people who are basically will adapt to solve the problem.

Andrew Huberman (1:52:03.200)

I like the analogy of the three meter target and the a hundred meter target.

Lex Fridman (1:52:07.200)

So the folks at Neuralink are basically many of them are some of the best people in the world at

Andrew Huberman (1:52:11.760)

the three meter target. Like you mentioned Matt and neurosurgery, like they're solving real problems.

Andrew Huberman (1:52:17.280)

There's no BS, philosophical smokes and weed and look back and look at the stars. But

Lex Fridman (1:52:26.480)

so both on Elon and because I think like this, I think it's really important to think about

Lex Fridman (1:52:31.920)

the hundred meter and the hundred meter is not even a hundred meter, but like

Andrew Huberman (1:52:36.560)

like the stuff behind the hill that's too far away, which is where I put consciousness. Maybe

Andrew Huberman (1:52:50.560)

I tend to believe that consciousness can be engineered. I mean, part of the reason,

Andrew Huberman (1:52:58.320)

part of the business I want to build leverages that idea that consciousness is a lot simpler

Lex Fridman (1:53:04.880)

than we've been talking about. Well, if someone can simplify the problem,

Andrew Huberman (1:53:10.160)

right, that will be wonderful. I mean, the reason we can talk about something as abstract as face

Andrew Huberman (1:53:14.640)

representations, infusive form face area is because Nancy Kanwisher had the brilliance

Andrew Huberman (1:53:19.760)

to tie it to the kind of lower level statistics of visual scenes. It wasn't because she was like,

Andrew Huberman (1:53:26.720)

oh, I bet it's there. That wouldn't have been interesting. So people like her understand how

Andrew Huberman (1:53:31.760)

to bridge that gap and they put a tractable definition. So I, so I just, I, that's what

Andrew Huberman (1:53:38.240)

I'm begging for in science is a tractable definition. This is what, but I want people

Andrew Huberman (1:53:44.320)

to sit in the, I want people who are really uncomfortable with woo woo, like consciousness,

Andrew Huberman (1:53:50.160)

like high level stuff to sit in that topic and sit uncomfortably because it forces them

Andrew Huberman (1:53:55.840)

to then try to ground and simplify it into something that's concrete because too many

Andrew Huberman (1:54:00.560)

people are just uncomfortable to sit in the consciousness room because there's no definitions.

Andrew Huberman (1:54:05.760)

It's like attention or, or intelligence in the artificial intelligence community. But the reality

Andrew Huberman (1:54:11.200)

is it's easy to avoid that room altogether, which is what, I mean, there's analogies to everything

Andrew Huberman (1:54:16.720)

you've said with the artificial intelligence community with Minsky and even Alan Turing that

Andrew Huberman (1:54:22.800)

talked about intelligence a lot. And then they drew a lot of funding and then it crashed because

Andrew Huberman (1:54:27.280)

they really didn't do anything with it. And it was a lot of force of personality and so on. But that

Andrew Huberman (1:54:31.920)

doesn't mean the topic of the Turing test and intelligence isn't something we should sit on

Lex Fridman (1:54:38.960)

and think like, think like, what is, well, first of all, Turing actually attempted this with the

Andrew Huberman (1:54:44.480)

Turing test. He tried to make concrete this very question of intelligence. It doesn't mean that

Andrew Huberman (1:54:49.520)

we shouldn't linger on it. And we shouldn't forget that ultimately that is what our efforts are all

Andrew Huberman (1:54:58.320)

about in the artificial intelligence community. And in the people, whether it's neuroscience or

Andrew Huberman (1:55:04.800)

whatever bigger umbrella you want to use for understanding the mind, the goal is not just

Andrew Huberman (1:55:11.680)

about understanding layer two or three of the vision. It's, it's to understand consciousness

Lex Fridman (1:55:18.400)

and intelligence and maybe create it or just all the possible biggest questions of our universe.

Lex Fridman (1:55:25.840)

That's, that's ultimately the dream. Absolutely. And I think what I really

Andrew Huberman (1:55:30.320)

appreciate about what you're saying is that everybody, whether or not they're working on a

Andrew Huberman (1:55:34.720)

kind of a low level synapse, that's like a reflex and the musculature or something very high level

Andrew Huberman (1:55:39.840)

abstract can benefit from looking at those who prefer three, you know, everyone's going after a

Andrew Huberman (1:55:45.840)

three meter, 10 meter and a hundred meter targets in some sense, but to be able to tolerate the

Andrew Huberman (1:55:50.800)

discomfort of being in a conversation where there are real answers, where the zeros and ones are,

Andrew Huberman (1:55:56.000)

are known zeros and ones are those, the equivalent of that in the nervous system.

Lex Fridman (1:56:00.400)

And also, as you said, for the people that are very much like, Oh, I can only trust what I can

Andrew Huberman (1:56:05.120)

see and touch. Those people need to put themselves into the discomfort of the high level conversation

Andrew Huberman (1:56:10.160)

because what's missing is conversation and conceptualization of things at multiple levels.

Andrew Huberman (1:56:19.360)

I think one of the, this is, um, I don't gripe about my life's been fortunate. We've been funded

Andrew Huberman (1:56:24.160)

from the start and we've been happy, um, in that, in that regard and lucky, and we're grateful for

Andrew Huberman (1:56:29.920)

that. But I think one of the challenges of research being so expensive is that there isn't a lot of

Andrew Huberman (1:56:37.440)

time, especially nowadays for people to just convene around a topic because there's so much

Andrew Huberman (1:56:43.200)

emphasis on productivity. Um, and so there, there are actually, believe it or not, there aren't that

Andrew Huberman (1:56:48.400)

many concepts, formal concepts in neuroscience right now. The last 10 years has been this huge

Andrew Huberman (1:56:54.480)

influx of tools. And so people in neural circuits and probing around and connect homes, it's been

Andrew Huberman (1:56:59.440)

wonderful, but w you know, 10, 20 years ago, when the consciousness stuff was more prominent,

Andrew Huberman (1:57:05.600)

the C word, as you said, um, what was good about that time is that people would go to meetings and

Andrew Huberman (1:57:11.280)

actually discuss ideas and models. Now it's sort of like, it's sort of like demonstration day at

Andrew Huberman (1:57:18.080)

the school science fair where everyone's got their thing and some stuff is cooler than others.

Andrew Huberman (1:57:22.880)

But, um, I think we're going to see a shift. I'm grateful that we have so many computer scientists

Lex Fridman (1:57:29.600)

and theoreticians and, um, or theorists, I think they call themselves. Um, and somebody tell me

Lex Fridman (1:57:36.400)

what the difference is someday. Um, and you know, psychology and even dare I say philosophy,

Andrew Huberman (1:57:43.440)

you know, these things are starting to converge. We, you know, neuroscience that the name

Andrew Huberman (1:57:46.800)

neuroscience, there wasn't even such a thing when I started graduate school or as a postdoc,

Andrew Huberman (1:57:50.880)

it was neurophysiology or you were a neuro anatomist or what now every it's sort of

Andrew Huberman (1:57:56.160)

everybody's invited and that's beautiful. That means that something's useful is going to come

Andrew Huberman (1:58:00.480)

of all this. And there's also tremendous work of course happening on it for the treatment of disease

Lex Fridman (1:58:04.800)

and we shouldn't overlook that. That's where, you know, endings, you know, eliminating,

Andrew Huberman (1:58:08.560)

reducing suffering is also a huge initiative in neuroscience. So there's a lot of beauty in the

Andrew Huberman (1:58:13.200)

field, but the consciousness thing continues to be a, uh, it's like an exotic bird. It's like,

Lex Fridman (1:58:20.560)

no one really quite knows how to handle it and it dies very easily.

Andrew Huberman (1:58:24.160)

Well, yeah, I think also from the AI perspective, I, uh, so I view the brain as less sacred. Uh,

Andrew Huberman (1:58:36.480)

I think from a neuroscience perspective, you're a little bit more sensitive to BS,

Andrew Huberman (1:58:42.880)

like BS narratives about the brain or whatever. I'm a little bit more, uh, comfortable with just

Andrew Huberman (1:58:49.840)

poetic BS about the brain as long as it helps engineer intelligence systems. Well, you know

Lex Fridman (1:58:54.960)

what I mean? Well, and I have to, you know, I confess, um, ignorance when it comes to,

Lex Fridman (1:59:00.400)

you know, most things about coding and I'm, I'm have some quantitative ability,

Lex Fridman (1:59:04.000)

but I don't have strong quantitative leanings. And so I know my limitations too. And so I,

Andrew Huberman (1:59:09.600)

I think the next generation coming up, you know, a lot of the students at Stanford are really

Andrew Huberman (1:59:13.360)

interested in quantitative models and theory and AI. And I remember when I was coming up, um,

Andrew Huberman (1:59:20.160)

a lot of the people who were doing work ahead of me, I kind of rolled my eyes at some of the stuff

Andrew Huberman (1:59:23.440)

they were doing, um, including some of their personalities, although I have many great,

Andrew Huberman (1:59:27.200)

um, senior colleagues, uh, everywhere in the world. So it's the way of the world. So nobody

Andrew Huberman (1:59:32.000)

knows what it's like to be a, you know, a young graduate student in 2020, except the young graduate

Andrew Huberman (1:59:36.560)

students. So I, I know what I, I'm, I know there are a lot of things I don't know. And, um, in

Andrew Huberman (1:59:42.320)

addition to wanting to do a lot of public education, increased scientific literacy and

Andrew Huberman (1:59:45.360)

neuroscientific thinking, et cetera, a big goal of mine is to try and at least pave the way so that

Andrew Huberman (1:59:51.680)

these really brilliant and forward thinking, um, younger scientists can make the biggest

Andrew Huberman (1:59:56.160)

possible dent and make what will eventually be all us old guys and gals look stupid. I mean,

Andrew Huberman (20:05.280)

jumping out of the plane. However, the forward movement in the face of threat was linked to the

Andrew Huberman (20:13.520)

activation of what we call collateral, which means just a side connection, literally a wire in the

Andrew Huberman (20:18.080)

brain that connects to the dopamine circuits for reward. And so when one safely and adaptively,

Andrew Huberman (20:25.360)

meaning you survive, moves through a threat or toward a threat, it's rewarded as a positive

Andrew Huberman (20:31.360)

experience. And so the key, it actually maps very well to cognitive behavioral therapy and

Andrew Huberman (20:36.880)

a lot of the existing treatments for trauma is that you have to confront the thing that

Andrew Huberman (20:42.640)

makes you afraid. So otherwise you exist in this very low level of reverberatory circuit activity

Andrew Huberman (20:48.960)

where the circuits for autonomic arousal are humming and they're humming more and more and

Andrew Huberman (20:53.760)

more. And we have to remember that stress and fear and threat were designed to agitate us so

Andrew Huberman (20:58.640)

that we actually move. So the reason I mentioned this is I think a lot of times people think that

Andrew Huberman (21:04.480)

the maximum stress response or fear response is to freeze and to lock up. But that's actually not

Andrew Huberman (21:10.880)

the maximum stress response. The maximum stress response is to advance, but it's associated with

Andrew Huberman (21:16.720)

reward. It has positive valence. So there's this kind of, everyone always thinks about the bell

Andrew Huberman (21:22.080)

shape, you know, the sort of hump shape curve for, you know, at low levels arousal performance is low

Lex Fridman (21:28.160)

and as the increases performance goes higher and then it drops off as you get really stressed.

Lex Fridman (21:31.680)

But there's another bump further out that distribution where you perform very well under

Andrew Huberman (21:36.960)

very high levels of stress. And so we've been spending a lot of time in humans and in animals

Andrew Huberman (21:41.120)

exploring what it takes to get people comfortable to go to that place and also to let them experience

Lex Fridman (21:48.800)

how there are heightened states of cognition there. There's changes in time perception that

Andrew Huberman (21:54.080)

allow you to evaluate your environment at a faster frame rate, essentially. This is the matrix as a

Andrew Huberman (22:01.040)

lot of people think of it. But we tend to think about fear as all the low level stuff where

Andrew Huberman (22:06.240)

things aren't worked out, but there are a lot of different features to the fear response.

Lex Fridman (22:13.840)

And so we think about it quantitatively and we think about it from a circuit perspective

Andrew Huberman (22:18.080)

in terms of outcomes. And we try and weigh that against the threat. So we never want people to

Andrew Huberman (22:22.960)

put themselves in unnecessary risk, but that's where the VR is fun because you can push people

Andrew Huberman (22:27.360)

hard without risk of physically injuring them. And that's like you said, the little bump that

Andrew Huberman (22:33.520)

seems to be a very small fraction of the human experience, right? So it's kind of fascinating

Andrew Huberman (22:38.240)

to study it because most of us move through life without ever experiencing that kind of focus.

Andrew Huberman (22:48.160)

Well, everything's in a peak state there. I really think that's where optimal performance lies.

Lex Fridman (22:53.280)

There's so many interesting words here, but what's performance? And what's optimal performance?

Andrew Huberman (22:59.440)

We're talking about mental ability to what to perceive the environment quickly to make actions

Lex Fridman (23:07.280)

quickly. What's optimal performance? Yeah. Well, it's very subjective and it

Andrew Huberman (23:11.360)

varies depending on task and environment. So one way we can make it a little bit more

Andrew Huberman (23:17.040)

operational and concrete is to say there is a sweet spot, if you will, where the level of internal

Andrew Huberman (23:25.520)

autonomic arousal, AKA stress or alertness, whatever you want to call it, is ideally matched to the

Andrew Huberman (23:34.000)

speed of whatever challenge you have to be facing in the outside world. So we all have

Andrew Huberman (23:40.000)

perception of the outside world as exteroception and the perception of our internal real estate

Andrew Huberman (23:44.000)

interoception. And when those two things, when interoception and exteroception are matched along

Andrew Huberman (23:49.200)

a couple of dimensions, performance tends to increase or tends to be in an optimal range.

Lex Fridman (23:58.000)

So for instance, if you're, I don't play guitar, but I know you play guitar. So let's say you're

Andrew Huberman (24:01.760)

trying to learn something new on the guitar. I'm not saying that being in these super high

Andrew Huberman (24:06.880)

states of activation are the best place for you to be in order to learn. It may be that your

Andrew Huberman (24:13.200)

internal arousal needs to be at a level where your analysis of space and time has to be well matched

Andrew Huberman (24:20.080)

to the information coming in and what you're trying to do in terms of performance, in terms of

Andrew Huberman (24:25.760)

playing chords and notes and so forth. Now, in these cases of high threat where things are coming

Andrew Huberman (24:31.120)

in quickly and animals and humans need to react very quickly, the higher your state of autonomic

Andrew Huberman (24:36.640)

arousal, the better because you're slicing time more finely just because of the way the autonomic

Andrew Huberman (24:42.560)

system works. The pupil dilation, for instance, and movement of the lens essentially changes your

Andrew Huberman (24:49.600)

optics and that's obvious. But with the change in optics is a change in how you bin time and

Andrew Huberman (24:55.360)

slice time, which allows you to get more frames per second readout. With the guitar learning, for

Andrew Huberman (25:00.960)

instance, it might actually be that you want to be almost sleepy, almost in a drowsy state to be able

Andrew Huberman (25:09.120)

to, and I don't play music, so I'm guessing here, but sense some of the nuance in the chords or the

Andrew Huberman (25:14.400)

ways to be relaxed enough that your fingers can follow an external cue. So matching the movement

Andrew Huberman (25:19.520)

of your fingers to something that's pure exteroception. And so there is no perfect

Andrew Huberman (25:25.680)

autonomic state for performance. This is why I don't favor terms like flow because they're not

Andrew Huberman (25:34.160)

well operationally defined enough. But I do believe that optimal or peak performance is

Andrew Huberman (25:41.120)

going to arise when internal state is ideally matched to the space time features of the external

Andrew Huberman (25:48.560)

demands. So there's some slicing of time that happens and then you're able to adjust, slice

Andrew Huberman (25:54.880)

time more finely or more, less finely in order to adjust to the stimulus, the dynamics of the

Andrew Huberman (26:01.920)

stimulus. What about the realm of ideas? So like, you know, I'm a big believer, this guy named

Andrew Huberman (26:10.560)

Cal Newport who wrote a book about deep work. Yeah, I love that book. Yeah, he's great. I mean,

Andrew Huberman (26:18.640)

one of the nice things, I've always practiced deep work, but it's always nice to have words

Andrew Huberman (26:25.920)

put to the concepts that you've practiced. It somehow makes them more concrete and allows you

Andrew Huberman (26:32.480)

to get better. It turns it into a skill that you can get better at. But, you know, I also value

Andrew Huberman (26:38.320)

deep thinking where you think it's almost meditative. You think about a particular

Andrew Huberman (26:45.840)

concept for long periods of time. The programming you have to do that kind of thing for. You just

Andrew Huberman (26:50.640)

have to hold this concept, like you hold it and then you take steps with it. You take further

Andrew Huberman (26:56.880)

steps and you're holding relatively complicated things in your mind as you're thinking about them.

Lex Fridman (27:03.040)

And there's a lot of, I mean, the hardest part is there's frustrating things like you take a step

Lex Fridman (27:10.240)

and it turns out to be the wrong direction. So you have to calmly turn around and take a step back.

Lex Fridman (27:14.960)

And then it's, you kind of like exploring through the space of ideas. Is there something about

Andrew Huberman (27:20.000)

your study of optimal performance that can be applied to the act of thinking as opposed to

Andrew Huberman (27:26.640)

action? Well, we haven't done too much work there, but I think I can comment on it from a neuroscience

Andrew Huberman (27:33.840)

perspective, which is really all I do is, well, I mean, we do experiments in the lab, but I'm

Andrew Huberman (27:38.720)

looking at things through the lens of neuroscience. So what you're describing can be mapped fairly

Andrew Huberman (27:44.400)

well to working memory, just keeping things online and updating them as they change in information

Andrew Huberman (27:51.440)

is coming back into your brain. Jack Feldman, who I'm a huge fan of and fortunate to be friends

Andrew Huberman (27:58.880)

with is a professor at UCLA, works on respiration and breathing, but he has a physics background.

Lex Fridman (28:05.600)

And so he thinks about respiration and breathing in terms of ground states and how they modulate

Andrew Huberman (28:10.560)

other states. Very, very interesting and I think important work. Jack has an answer to your

Andrew Huberman (28:17.600)

question. So I'm not going to get this exactly right because this is lifted from a coffee

Andrew Huberman (28:21.440)

conversation that we had about a month ago. So apologies in advance, but I think I can get mostly

Andrew Huberman (28:28.560)

right. So we were talking about this, about how the brain updates cognitive states depending on

Andrew Huberman (28:34.880)

demands and thinking in particular. And he used an interesting example. I'd be curious to know if you

Andrew Huberman (28:40.160)

agree or disagree. He said, most great mathematics is done by people in their late teens and 20s,

Lex Fridman (28:49.280)

and even you could say early 20s, sometimes into the late 20s, but not much further on. Maybe I

Andrew Huberman (28:54.880)

just insulted some mathematicians. No, that's true. And I think that it demands, his argument

Andrew Huberman (29:00.560)

was there's a tremendous demand on working memory to work out theorems in math and to keep a number

Andrew Huberman (29:07.280)

of plates spinning, so to speak mentally and run back and forth between them, updating them.

Andrew Huberman (29:12.240)

In physics, Jack said, and I think this makes sense to me too, that there's a reliance on

Andrew Huberman (29:20.400)

working memory, but an increased reliance on some deep memory and deep memory stores,

Andrew Huberman (29:27.840)

probably stuff that's moved out of the hippocampus and forebrain and into the cortex and is some

Andrew Huberman (29:34.720)

episodic and declarative stuff, but really, so you're pulling from your library, basically. It's

Andrew Huberman (29:39.200)

not all RAM, it's not all working memory. And then in biology, and physicists tend to have

Andrew Huberman (29:44.640)

very active careers into their 30s and 40s and 50s and so forth, sometimes later. And then in

Andrew Huberman (29:50.880)

biology, you see careers that have a much longer arc, these protracted careers often, people still

Andrew Huberman (29:57.840)

in their 60s and 70s doing really terrific work, not always doing it with their own hands because

Andrew Huberman (2:00:01.680)

that's, that's what we were all trying to do. That's what we were trying to do. So yeah.

Andrew Huberman (2:00:05.440)

Yeah. So from the highest possible topic of consciousness to the, to the lowest level,

Lex Fridman (2:00:14.560)

uh, topic of David Goggins, uh, let's go.

Andrew Huberman (2:00:18.880)

I don't know if it's low, low level. He's high performance.

Andrew Huberman (2:00:22.480)

High performance, but like low, like there's no, I don't think David has any time for philosophy.

Andrew Huberman (2:00:30.480)

Let's just put it this way. Uh,

Andrew Huberman (2:00:32.560)

well, it's, I mean, I think we can tack it to what we were just saying in a, in a,

Andrew Huberman (2:00:36.160)

in a meaningful way, which is whatever goes on in that abstraction part of the brain,

Andrew Huberman (2:00:43.280)

he's figured, you know, he's figured out how to dig down in whatever the limbic friction.

Andrew Huberman (2:00:48.880)

Yeah.

Lex Fridman (2:00:49.440)

He's figured out how to grab ahold of that,

Andrew Huberman (2:00:52.880)

scruff it and send it in the direction that he's decided it needs to go. And what's wild is that

Andrew Huberman (2:00:59.280)

he's, what we're talking about is him doing that to himself, right? He's, it's like he's scruffing

Andrew Huberman (2:01:04.720)

himself and directing himself in a particular direction and sending himself down that trajectory.

Lex Fridman (2:01:11.920)

And he, what's beautiful is that he acknowledges that that process is not pretty. It doesn't feel

Andrew Huberman (2:01:19.280)

good. It's kind of horrible at every level, but he's created this rewarding element to it. And I

Andrew Huberman (2:01:27.120)

think that's, what's so it, it's so admirable. And it's what so many people crave, which is

Andrew Huberman (2:01:33.760)

regulation of the self at that level.

Lex Fridman (2:01:36.800)

And he practices, I mean, there's a ritual to it. There's a, every single day, like no exceptions.

Andrew Huberman (2:01:44.240)

There's a practice aspect to the suffering that he goes through.

Lex Fridman (2:01:48.960)

It's principled suffering.

Andrew Huberman (2:01:50.800)

Principled suffering.

Lex Fridman (2:01:51.760)

It is.

Andrew Huberman (2:01:52.400)

I mean, I just, I mean, I admire all aspects of it, including him and his girlfriend slash wife.

Lex Fridman (2:01:58.160)

I'm not sure. She'll probably know this.

Andrew Huberman (2:01:59.520)

I don't know.

Lex Fridman (2:01:59.760)

Fiance.

Andrew Huberman (2:02:00.640)

Wonderful person.

Lex Fridman (2:02:01.360)

I'm not asking him.

Andrew Huberman (2:02:02.000)

No, no. We've only communicated, I've only communicated with her by text about some stuff

Lex Fridman (2:02:08.880)

I was asking David, but yeah, they clearly formed a powerful team.

Lex Fridman (2:02:14.720)

And it's a beautiful thing to see people working in that kind of synergy.

Lex Fridman (2:02:18.800)

And it's inspiring to me, same as with Elon, that a guy like David Goggins can find love.

Andrew Huberman (2:02:25.840)

That you find a thing that works, which gives me hope that like whatever,

Andrew Huberman (2:02:30.960)

whatever flavor of crazy I am, you can always find another thing that works with that.

Lex Fridman (2:02:37.440)

But I, I've had the, so maybe let's trade Goggins stories.

Andrew Huberman (2:02:44.480)

Uh, you from a neuroscience perspective, me from a, uh, self inflicted pain perspective,

Andrew Huberman (2:02:50.720)

I somehow found myself in communication with David about some challenges that I was undergoing.

Lex Fridman (2:03:01.360)

One of which is we were communicating every single day, email, phone,

Andrew Huberman (2:03:06.480)

about a particular 30 day challenge that I did.

Lex Fridman (2:03:09.120)

That stretched for longer of, uh, pushups and pullups.

Lex Fridman (2:03:12.800)

And you made a call out on social media.

Lex Fridman (2:03:14.960)

Yeah. Social media was dumb.

Andrew Huberman (2:03:16.080)

Actually, I think that was the point I, I knew of you before,

Lex Fridman (2:03:19.600)

but that's where I started tracking some of what you were doing with these physical challenges.

Lex Fridman (2:03:22.960)

And I, um, well, no, I think I actually, I don't often comment on people's stuff,

Lex Fridman (2:03:28.480)

but I think I commented something like, uh, neuroplasticity loves a nonnegotiable rule.

Andrew Huberman (2:03:33.680)

No, I said a nonnegotiable contract because at the point where neuroplasticity really loves a

Andrew Huberman (2:03:40.080)

nonnegotiable contract, because, you know, and I've said this before, so forgive me,

Lex Fridman (2:03:45.520)

but you know, the brain is doing analysis of duration, path and outcome.

Lex Fridman (2:03:49.360)

And that's a lot of work for the brain. And the more that it can pass off duration,

Andrew Huberman (2:03:54.000)

path and outcome to just reflex, the more energy and it can allocate to other things.

Lex Fridman (2:04:00.240)

So if you decide there's no negotiation about how many pushups, how far I'm going to run,

Lex Fridman (2:04:06.160)

how many days, how many pullups, et cetera, you actually have more energy for pushups,

Lex Fridman (2:04:10.480)

running and pullups.

Lex Fridman (2:04:11.520)

And when you say neuroplasticity, you mean like the brain, once the decision is made,

Andrew Huberman (2:04:15.520)

it'll start rewiring stuff to, to make sure that this, we can actually make this happen.

Andrew Huberman (2:04:20.640)

That's right. I mean, so much of what we do is reflexive at the level of just

Lex Fridman (2:04:23.840)

core circuitry, breathing, heart rate, all that, that boring stuff, digestion.

Lex Fridman (2:04:27.440)

But then there's a lot of reflexive stuff, like how you drink out of a mug of coffee

Andrew Huberman (2:04:31.760)

that's reflexive too, but that you had to learn at some point in your life earlier

Andrew Huberman (2:04:35.920)

when you were very little, analyzing duration, path and outcome.

Lex Fridman (2:04:38.720)

And that involves a lot of top down processing with the prefrontal cortex,

Lex Fridman (2:04:42.240)

but through plasticity mechanisms, you now do it. So when you take on a challenge,

Andrew Huberman (2:04:47.120)

provided that you understand the core mechanics of how to run pushups and pullups and whatever

Andrew Huberman (2:04:52.080)

else you decided to do, once you set the number and the duration and all that,

Andrew Huberman (2:04:57.520)

then you, all you have to do is just go, but people get caught in that tide pool of just,

Andrew Huberman (2:05:03.120)

well, do I really have to do it? How do I not do that? What if I get injured? What if I,

Andrew Huberman (2:05:06.400)

you know, can I sneak a this or that, you know? And that's work. And to some extent,

Andrew Huberman (2:05:12.400)

I look, I not David Goggins, obviously, nor, nor do I claim to understand his process

Andrew Huberman (2:05:20.480)

partially, you know, but maybe a little bit, which is that it's clear that by making the decision,

Andrew Huberman (2:05:26.800)

there's more resources to devote to the effort of the actual execution.

Andrew Huberman (2:05:30.560)

Well, that's a really, like what you're saying was not a lesson that was obvious to me. And

Andrew Huberman (2:05:35.600)

it's still not obvious. It's something I really work at, which is there is always an option to

Andrew Huberman (2:05:40.080)

quit. And I mean, that's something I really struggle with. I mean, I've quit some things

Andrew Huberman (2:05:47.680)

in my life, sick, stupid stuff. And, uh, one lesson I've learned is if you quit once,

Andrew Huberman (2:05:57.920)

it opens the door that like, it's really valuable to trick your brain into thinking

Andrew Huberman (2:06:07.760)

that you're, you're going to have to die before you quit. Like it's actually really convenient.

Lex Fridman (2:06:12.880)

So actually what you're saying is very profound, but you shouldn't intellectualize it. Like

Andrew Huberman (2:06:19.760)

it took me time to develop like psychologically in ways that I think it would be another

Andrew Huberman (2:06:27.520)

conversation, cause I'm not sure how to put it into words, but it's really tough on me to, uh,

Andrew Huberman (2:06:32.960)

to do certain parts of that challenge, which is a huge, you know, is a huge output. The number,

Andrew Huberman (2:06:38.320)

the number that I was, I thought it would be, the number would be hard, but it's not. It's

Andrew Huberman (2:06:42.560)

the entirety of it. Uh, especially in the early days was just spending a kind of embarrassed to

Andrew Huberman (2:06:52.640)

say how many hours this took. So I didn't say publicly how many hours, cause people,

Lex Fridman (2:06:58.320)

I knew people would be like, don't you, aren't you supposed to do other stuff?

Andrew Huberman (2:07:03.200)

Well, it's, um, again, I don't want to speculate too much, but occasionally David has said this

Andrew Huberman (2:07:08.320)

publicly where people will be like, don't you sleep or something. And his process used to just

Andrew Huberman (2:07:13.200)

be that he would just block delete, you know, like gone, but it's, it's actually, um, it's,

Andrew Huberman (2:07:18.880)

it's a super interesting topic. And because self control and directing our actions and the role of

Andrew Huberman (2:07:26.480)

emotion and quitting, these are, these are vital to the human experience and they're vital to

Andrew Huberman (2:07:32.320)

performing well at anything. And at a high, obviously at a super high level, being able to

Andrew Huberman (2:07:37.280)

understand this about the self is crucial. Um, so I have a friend who was also in the teams.

Andrew Huberman (2:07:44.000)

His name is Pat Dossett. He did nine years in the seal teams. Um, and in a similar way,

Andrew Huberman (2:07:49.840)

there's, there's a lore about him among team guys, um, because of a kind of funny challenge he gave

Andrew Huberman (2:07:55.840)

himself, which was, so he and I swim together, although he swims for a long time. Um, and he

Andrew Huberman (2:08:00.960)

doesn't swim together, although he swims further up front than I do. Um, and he's very patient. Um,

Lex Fridman (2:08:06.880)

but you know, he was on a, uh, he was assigned when he was in the teams to a position that gave

Andrew Huberman (2:08:13.440)

him a little more time behind a desk than he wanted. And it's not as much time out out and

Andrew Huberman (2:08:17.360)

deployments, although he did deployments. Um, so he didn't know what to do at that time,

Lex Fridman (2:08:21.760)

but he thought about it and he asked himself, what, what does he hate the most? And it turns

Andrew Huberman (2:08:26.160)

out the thing that he hated doing the most was bear crawls, you know, walking on your hands and

Lex Fridman (2:08:30.080)

so he decided to bear crawl for a mile for time. So he was bear crawling a mile a day.

Andrew Huberman (2:08:34.400)

Right. And I thought that was an interesting example that he gave because, you know, like

Lex Fridman (2:08:38.960)

why pick the thing you hate the most? And I think it maps right back to limbic friction.

Andrew Huberman (2:08:44.080)

It's the thing that creates the most limbic friction. And so if you can overcome that,

Andrew Huberman (2:08:48.640)

then there's carry over. And I think the notion of carry over has been talked about psychologically

Lex Fridman (2:08:53.200)

and in kind of in the self help space, like, Oh, if you run a marathon, it's going to help you in

Andrew Huberman (2:08:56.560)

other areas of life, but will it really will it? Well, I think it depends on whether or not there's

Andrew Huberman (2:09:00.880)

a lot of limbic friction because if there is what you're exercising is not a circuit for bear crawls

Andrew Huberman (2:09:07.120)

or a circuit for pull ups. What you're doing is you're exercising a circuit for top down control

Lex Fridman (2:09:12.240)

and that circuit was not designed to be for bear crawls or pull ups or coding

Andrew Huberman (2:09:17.920)

or waking up in the middle of the night to do something hard. That circuit was designed to

Andrew Huberman (2:09:22.320)

override limbic friction. And so neural circuits were designed to generalize, right? The stress

Andrew Huberman (2:09:28.640)

response to an incoming threat that's a physical threat was designed to feel the same way and be

Andrew Huberman (2:09:34.400)

the same response internally as the threat to an impending exam or divorce or marriage or whatever

Andrew Huberman (2:09:40.720)

it is that's stressing somebody out. And so neural circuits are not designed to be for one particular

Andrew Huberman (2:09:46.640)

action or purpose. So if you can, as you did, if you can train up top down control under conditions

Andrew Huberman (2:09:52.640)

of the highest limbic friction that when the desire to quit is at its utmost, either because

Andrew Huberman (2:09:58.640)

of fatigue or hyper arousal, being too stressed or too tired, you're learning how to engage a

Andrew Huberman (2:10:05.520)

circuit and that circuit is forever with you. And if you don't engage it, it sits there, but it's

Andrew Huberman (2:10:12.400)

atrophied. It's like a plant that doesn't get any water. And a lot of this has been discussed in

Andrew Huberman (2:10:17.840)

self help and growth mindset and all these kinds of ideas that circle the internet and social media.

Lex Fridman (2:10:23.040)

But when you start to think about how they map to neural circuits, I think there's some utility

Andrew Huberman (2:10:26.800)

because what it means is that the limbic friction that you'll experience in, I don't know, maybe

Andrew Huberman (2:10:31.920)

some future relationship to something or someone, it's a category of neural processing that should

Andrew Huberman (2:10:38.880)

immediately click into place. It's just like the limbic friction you experienced trying to engage

Andrew Huberman (2:10:43.680)

in the God knows how many pushups, pull ups and running runs you were doing.

Lex Fridman (2:10:49.520)

25,000. Who's counting?

Lex Fridman (2:10:52.000)

So folks, if Lex does this again, more comments, more likes. This is the problem with you getting

Andrew Huberman (2:11:00.080)

more followers is you're going to get more. Actually, I should say that's the benefit.

Andrew Huberman (2:11:04.000)

I don't know. Maybe it's not politically correct for me to ask, but there is this

Andrew Huberman (2:11:07.680)

a stereotype about Russians being like being really durable. And I started going to that

Andrew Huberman (2:11:17.760)

Russian banya that way back before COVID and they could tolerate a lot of heat and they would sit

Andrew Huberman (2:11:25.760)

very stoic. No one was going, oh, it's hot in here. They're just kind of like ease into it.

Lex Fridman (2:11:30.800)

So maybe there's something there, who knows?

Andrew Huberman (2:11:32.320)

Might be something there, but it could be also just personal. I just have some, I found myself,

Andrew Huberman (2:11:38.640)

everyone's different, but I've found myself to be able to do something unpleasant for very long

Andrew Huberman (2:11:45.360)

periods of time. Like I'm able to shut off the mind and I don't think that's been fully tested.

Lex Fridman (2:11:53.360)

Monkey mind or the supercomputer?

Lex Fridman (2:11:55.040)

Well, it's interesting. I mean, which mind tells you to quit exactly?

Andrew Huberman (2:12:02.720)

Limbic. Limbic friction tells you.

Lex Fridman (2:12:05.120)

Well, limbic friction is the source of that, but who are you talking with exactly?

Lex Fridman (2:12:09.120)

So there's a, we can put something very concrete to that. So there's a

Andrew Huberman (2:12:13.520)

paper published in Cell, super top tier journal, two years ago, looking at effort.

Lex Fridman (2:12:21.280)

And this was in a visual environment of trying to swim forward toward a target and a reward.

Lex Fridman (2:12:26.640)

And it was a really cool experiment because they manipulated virtually the visual environment. So

Andrew Huberman (2:12:32.560)

the same amount of effort was being expended every time. But sometimes the perception was

Andrew Huberman (2:12:36.480)

you're making forward progress. And sometimes the perception was you're making no progress

Andrew Huberman (2:12:40.400)

because stuff wasn't drifting by meant no progress. So you can be swimming and swimming

Lex Fridman (2:12:44.800)

and swimming and not making progress. And it turns out that with each bout of effort, there's epinephrine

Lex Fridman (2:12:52.720)

and norepinephrine is being released in the brainstem and glia, what traditionally were

Andrew Huberman (2:12:58.800)

thought of as support cells for the neurons, but they do a lot of things actively too,

Andrew Huberman (2:13:02.560)

are measuring the amount of epinephrine and norepinephrine in that circuit.

Lex Fridman (2:13:06.720)

And when it exceeds a certain threshold, the glia send inhibitory signals that shut down

Andrew Huberman (2:13:11.200)

top down control. They literally it's the quit. You stop. There's no more. It's you quit enduring.

Andrew Huberman (2:13:18.960)

It can be rescued. Endurance can be rescued with dopamine. So that's where the subjective part

Andrew Huberman (2:13:28.560)

really comes into play. So you quit because you've learned how to turn that off or you've

Andrew Huberman (2:13:34.800)

learned how to, some people will reward the pain process so much that friction becomes the reward.

Lex Fridman (2:13:41.360)

And when you talk about people like Goggins and other people I know from special operations and

Andrew Huberman (2:13:46.320)

people have gone through cancer treatments three times, you hear about, just when you hear about

Andrew Huberman (2:13:52.240)

people, the Viktor Frankl stories, I mean, you hear about Nelson Mandela, you hear about these

Andrew Huberman (2:13:56.400)

stories. I'm sure the same process is involved. Again, this speaks to the generalizability of

Andrew Huberman (2:14:01.520)

these processes as opposed to a neural circuit for a particular action or cognitive function.

Lex Fridman (2:14:06.320)

So I think you have to learn to subjectively self reward in a way that replenishes you.

Andrew Huberman (2:14:13.360)

Goggins talks about eating souls. It's a very dramatic example in his mind, apparently that's

Andrew Huberman (2:14:19.840)

a form of reward, but it's not just a form of reward where it's like you're picking up a trophy

Andrew Huberman (2:14:26.240)

or something. It's actually, it gives you energy. It's a reward that gives more neural energy. And

Andrew Huberman (2:14:33.440)

I'm defining that as more dopamine to suppress the noradrenaline adrenaline circuits in the

Andrew Huberman (2:14:39.120)

brainstem. So ultimately maps to that. Yeah. He creates enemies. He's always fighting enemies.

Andrew Huberman (2:14:45.280)

I never, I think I have enemies, but there are usually just versions of me inside my head. So

Andrew Huberman (2:14:51.440)

I thought about through that 30 day challenge, I tried to come up with like fake enemies. It wasn't

Andrew Huberman (2:14:57.920)

working. The only enemy I came up with is David. Well, now you have a, you certainly have a form

Andrew Huberman (2:15:06.320)

formidable adversary in this one. I don't care. I'm David. I'm willing to die on this one. So let's

Andrew Huberman (2:15:12.320)

go there. Well, let's hope you both survive this one. My problem is the physical. So everything

Andrew Huberman (2:15:22.400)

we've been talking about in the mind, there's a physical aspect that's just practically difficult,

Andrew Huberman (2:15:27.920)

which is like, I can't like, you know, when you injure yourself at a certain point, like you just

Andrew Huberman (2:15:33.920)

can't function or you're doing more damage. Yeah. Talking about it, taking yourself out of running

Andrew Huberman (2:15:39.120)

for the rest of your life potentially, or like, you know, or did it for years. So, you know,

Andrew Huberman (2:15:45.920)

I'd love to avoid that, right? There's just like stupid physical stuff that you just want to avoid.

Andrew Huberman (2:15:52.960)

You want to keep it purely in the mental. And if it's purely in the mental, that's when the race

Andrew Huberman (2:15:57.760)

is interesting. But yeah, the problem with these physical challenges as David has experienced,

Andrew Huberman (2:16:03.360)

I mean, it has a toll on your body. I tend to think of the mind is limitless and the body is

Andrew Huberman (2:16:09.520)

kind of unfortunately quite limited. Well, I think the key is to dynamically control your output.

Lex Fridman (2:16:15.840)

And that can be done by reducing effort, which doesn't work for throughout, but also by

Andrew Huberman (2:16:24.640)

restoring through these subjective reward processes. And we don't want to go down the

Andrew Huberman (2:16:30.240)

rabbit hole of why this all works, but these are ancient pathways that were designed to

Andrew Huberman (2:16:34.880)

bring resources to an animal or to a person through foraging for hunting or mates or water,

Andrew Huberman (2:16:40.640)

all these things. And they work so well because they're down in those circuits where we know the

Andrew Huberman (2:16:46.320)

zeros and ones. And that's great because it can be subjective at the level of, oh, I reached this

Andrew Huberman (2:16:52.480)

one milestone, this one horizon, this one three meter target. But if you don't reward it, it's

Andrew Huberman (2:17:00.320)

just effort. If you do self reward it, it's effort minus one in terms of the adrenaline output.

Andrew Huberman (2:17:07.680)

I have to ask you about this. You're one of the great communicators in science. I'm really a big

Andrew Huberman (2:17:16.640)

fan of yours, enjoying in terms of the educational stuff you're putting on neuroscience.

Lex Fridman (2:17:21.920)

Thank you.

Andrew Huberman (2:17:23.280)

What's the, do you have a philosophy behind it or is it just an instinct,

Andrew Huberman (2:17:30.960)

unstoppable force? Do you have, like, what's your thinking? Because it's rare and it's exciting.

Andrew Huberman (2:17:36.640)

I'm excited that, you know, somebody from Stanford. So I, okay, I'm in multiple places

Andrew Huberman (2:17:45.600)

in the sense of like where my interests lie. And one, you know, politically speaking, academic

Andrew Huberman (2:17:52.000)

institutions are under fire, you know, for many reasons we don't need to get into. I get into it

Andrew Huberman (2:17:59.360)

in a lot of other places, but I believe in places like Stanford and places like MIT as one of the

Andrew Huberman (2:18:10.720)

most magical institutions for inspiring people to dream, people to build the future. I mean,

Andrew Huberman (2:18:18.720)

it's, I believe that it is a really special, these universities are really special places.

Lex Fridman (2:18:24.720)

And so it's always exciting to me when somebody as inspiring as you represents those places. So

Andrew Huberman (2:18:33.440)

it makes me proud that somebody from Stanford is like, somebody like you is representing Stanford.

Lex Fridman (2:18:41.280)

So maybe you could speak to what's, how did you come to be who you are in being a communicator?

Andrew Huberman (2:18:52.400)

Well, first of all, thanks for the kind words, especially coming from you. I think Stanford is

Andrew Huberman (2:18:58.000)

an amazing place as is MIT and it's such a. MIT is better by the way. I'll let it out. Anything

Andrew Huberman (2:19:04.800)

you say at this point. I have many friends at MIT. Yeah. Smarter friends. Yeah. Ed Boyden is

Andrew Huberman (2:19:14.400)

among the best in class. There's some people, not me that can hold a candle to him, but not many,

Andrew Huberman (2:19:19.280)

maybe one or two. I think the great benefit of being in a place like MIT or Stanford is that

Andrew Huberman (2:19:25.840)

when you look around, the average is very high. You have many best in class among the one or two

Andrew Huberman (2:19:34.080)

or three best in the world at what they do. And it's a wonderful privilege to be there. And one

Andrew Huberman (2:19:40.160)

thing that I think also makes them and other universities like them very special is that

Andrew Huberman (2:19:44.880)

there's an emphasis on what gets exported out of the university, not keeping it ivory tower and

Andrew Huberman (2:19:50.480)

really trying to keep an eye on what's needed in the world and trying to do something useful.

Lex Fridman (2:19:55.600)

And I think the proximity to industry and Silicon Valley and in the Boston area and Cambridge also

Andrew Huberman (2:20:01.200)

lends itself well to that. And there are other institutions too, of course. So the reason I got

Andrew Huberman (2:20:07.200)

involved in educating on social media was actually because of Pat Dossett, the mile bear call guy.

Andrew Huberman (2:20:15.360)

It was at the turn of 2018 to 2019. We had formed a good friendship and he talked me into doing these

Andrew Huberman (2:20:22.640)

early morning cold water swims. I was learning a lot about pain and suffering, but also the beauty

Andrew Huberman (2:20:27.520)

of cold water swims. And we were talking one morning and he said, so what are you going to

Andrew Huberman (2:20:32.640)

do to serve the world in 2019? It's like, that's the way that like a Texan former seal talks.

Lex Fridman (2:20:37.760)

Like we're just literally like, what are you going to do to serve the world in 2019?

Andrew Huberman (2:20:40.640)

Like, well, I've run my lab. It's like, no, no, what are you going to do? That's new.

Lex Fridman (2:20:43.680)

And he wasn't forceful in it, but I was like, that's interesting question. I said, well,

Andrew Huberman (2:20:47.840)

if I had my way, I would just teach people, everyone about the brain. Because I think

Andrew Huberman (2:20:52.320)

it's amazing. He goes, we'll do it. I go, all right. He goes, shake on it. So we did it, you

Andrew Huberman (2:20:56.880)

know? And so I started putting out these posts and it's grown into, to include a variety of things,

Lex Fridman (2:21:04.080)

but you asked about a governing philosophy. So I want to increase interest in the brain and in the

Andrew Huberman (2:21:10.000)

nervous system and in biology generally, that's one major goal. I'd like to increase scientific

Andrew Huberman (2:21:15.200)

literacy, which can't be rammed down people's throats of talking about how to look at a graph

Lex Fridman (2:21:21.440)

and statistics and Z scores and P values and genetics. It has to be done gradually, in my

Andrew Huberman (2:21:27.440)

opinion. I want to put valuable tools into the world, mainly tools that map to things that we're

Andrew Huberman (2:21:34.320)

doing in our lab. So these will be tools centered around how to understand and direct one's states

Andrew Huberman (2:21:40.400)

of mind and body. So reduce stress, raise one's stress threshold. So it's not always just about

Andrew Huberman (2:21:45.520)

being calm. Sometimes it's about learning how to tolerate being not calm, raise awareness for

Andrew Huberman (2:21:51.760)

mental health. There's a ton of micro missions in this, but it all really maps back to, you know,

Andrew Huberman (2:21:58.560)

like the eight and 10 year old version of me, which is I used to spend my weekends when I was

Andrew Huberman (2:22:02.960)

a kid reading about weird animals. And I had this obsession with like medieval weapons and stuff

Andrew Huberman (2:22:07.840)

like catapults. And then I used to come into school on Monday and I would ask if I could talk

Andrew Huberman (2:22:12.720)

about it to the class and teach. And I just, it's really, I promise, and some people might

Andrew Huberman (2:22:18.320)

not believe me, but it's really, I don't really like being the point of focus. I just get so

Andrew Huberman (2:22:23.040)

excited about these gems of that I find in the world in books and in experiments and in

Andrew Huberman (2:22:30.080)

discussions with colleagues and discussions with people like you and around the universe.

Lex Fridman (2:22:34.960)

And I can't just compulsively, I got to tell people about it. So I try and package it into

Andrew Huberman (2:22:39.680)

a form that people can access. You know, I think if I've, I think the reception has been really

Andrew Huberman (2:22:44.480)

wonderful. Stanford has been very supportive, thankfully. I've done some podcasts even with

Andrew Huberman (2:22:51.040)

them and they've reposted some stuff on social media. It's a precarious place to put yourself

Andrew Huberman (2:22:55.760)

out there as a research academic. I think some of my colleagues, both locally and elsewhere,

Andrew Huberman (2:23:00.320)

probably wonder if I'm still serious about research, which I absolutely am. And I also

Andrew Huberman (2:23:05.680)

acknowledge that their research and the research coming out of the field needs to be talked about

Lex Fridman (2:23:13.200)

and not all scientists are good at translating that into a language that people can access.

Lex Fridman (2:23:18.880)

And I don't like the phrase dumb it down. What I like to do is take a concept that I think people

Andrew Huberman (2:23:25.520)

will find interesting and useful and offer it sort of like you would offer food to somebody visiting

Andrew Huberman (2:23:32.000)

your home. You're not going to cram foie gras in their face. You're going to say, like, do you want

Andrew Huberman (2:23:36.480)

a cracker? And they say, yeah. And like, do you want something on that cracker? Like, do you like

Lex Fridman (2:23:40.240)

cheese? Like, yeah. Like, do you want Swiss cheese or you want that really like stinky, like French?

Andrew Huberman (2:23:45.120)

I don't like cheese much. Or do you want foie gras? Like, what's that? Like, so you're trying,

Andrew Huberman (2:23:50.320)

the best information prompts more questions of interest, not questions of confusion,

Lex Fridman (2:23:55.760)

but questions of interest. And so I feel like one door opens, then another door opens,

Andrew Huberman (2:23:59.920)

then another door opens. And pretty soon, the image in my mind is you create a bunch of

Andrew Huberman (2:24:04.880)

neuroscientists who are thinking about themselves neuroscientifically. And I don't begin to think

Andrew Huberman (2:24:09.280)

that I have all the answers at all. I cast a neuroscience, sometimes a little bit of a psychology

Andrew Huberman (2:24:15.360)

lens onto what I think are interesting topics. And someday I'm going to go into the ground or

Andrew Huberman (2:24:23.920)

the ocean or wherever it is I end up. And I'm very comfortable with the fact that not everyone's

Andrew Huberman (2:24:31.520)

going to be happy with how I deliver the information, but I would hope that people

Andrew Huberman (2:24:34.960)

would feel like some of it was useful and meaningful and got them to think a little bit

Andrew Huberman (2:24:39.200)

harder. Since you mentioned going into the ground and Victor Frankl, Man's Search for Meaning,

Andrew Huberman (2:24:48.560)

I reread that book quite often. Let me ask the big ridiculous question about life. What do you

Andrew Huberman (2:25:02.000)

think is the meaning of it all? And maybe why do you, do you mention that book from a psychologist

Andrew Huberman (2:25:08.800)

perspective, which Victor Frankl was, or do you ever think about the bigger philosophical questions

Andrew Huberman (2:25:16.800)

that raises about meaning? What's the meaning of it all? One of the great challenges in assigning a

Andrew Huberman (2:25:25.840)

good, you know, giving a good answer to the question of like, what's the meaning of life is,

Andrew Huberman (2:25:29.680)

um, I think illustrated best by the Victor Frankl example, although there are other examples too,

Andrew Huberman (2:25:36.160)

which is that our sense of meaning is very elastic in time and space. And I'm, I'm,

Andrew Huberman (2:25:43.120)

uh, we talked a little bit about this earlier, but it's amazing to me that somebody locked in a cell

Andrew Huberman (2:25:49.280)

or a concentration camp can bring the horizon in close enough that they can then micro slice their

Andrew Huberman (2:25:56.400)

environment so that they can find rewards and meaning and power and beauty, even in a little

Andrew Huberman (2:26:03.280)

square box or, or a horrible situation. And I think this is really speaks to one of the most

Andrew Huberman (2:26:09.440)

important features of the human mind, which is we could do, let's take two opposite extremes.

Andrew Huberman (2:26:14.880)

One would be, let's say the alarm went off right now in this building and the building started

Andrew Huberman (2:26:19.360)

shaking our vision, our hearing, everything would be tuned to this space, time bubble for those

Andrew Huberman (2:26:26.960)

moments and everything that we were processed, all that would matter. The only meaning would be

Andrew Huberman (2:26:32.640)

get out of here, safe, figure out what's going on, contact loved ones, et cetera.

Andrew Huberman (2:26:36.160)

If we were to sit back, totally relaxed, we could do the, you know, I think it's called pale blue

Andrew Huberman (2:26:40.080)

dot thing or whatever, where we could imagine ourselves in this room. And then they were in

Andrew Huberman (2:26:43.360)

the United States and this continent and the earth, and then it's peering down us. And all of

Andrew Huberman (2:26:47.360)

a sudden you get back, it can seem so big that all of a sudden it's meaningless, right? If you

Andrew Huberman (2:26:53.040)

see yourself as just one brief glimmer in all of time and all of space, you go to, I don't matter.

Lex Fridman (2:27:00.880)

And if you go to, oh, every little thing that happens in this text thread or this, you know,

Andrew Huberman (2:27:06.240)

comment section on YouTube or Instagram, your space time bubble is tiny, then everything seems

Andrew Huberman (2:27:12.400)

inflated and the brain will contract and dilate its space, time, vision and time, but also sense

Andrew Huberman (2:27:22.560)

of meaning. And that's beautiful. And it's what allows us to be so dynamic in different environments

Lex Fridman (2:27:28.000)

and we can pull from the past and the present and future. It's why examples like Nelson Mandela and

Andrew Huberman (2:27:33.360)

Viktor Frankl had to include, it makes sense that it wasn't just about grinding it out. They had to

Andrew Huberman (2:27:39.280)

find those dopamine rewards, even in those little boxes they were forced into. So I'm not trying to

Andrew Huberman (2:27:46.640)

dodge an answer, but for me personally, and I think about this a lot because I have this complicated

Andrew Huberman (2:27:54.640)

history in science where my undergraduate, graduate advisor and postdoctoral advisor all died young.

Andrew Huberman (2:28:00.960)

So, you know, and they were wonderful people and had immense importance in my life. But what I

Andrew Huberman (2:28:07.920)

realized is that we can get so fixated on the thing that we're experiencing, holding tremendous

Andrew Huberman (2:28:15.040)

meaning, but it only holds that meaning for as long as we're in that space, time regime.

Lex Fridman (2:28:21.440)

And this is important because what really gives meaning is the understanding that you can move

Andrew Huberman (2:28:28.080)

between these different space, time dimensionalities. And I'm not trying to sound like a

Andrew Huberman (2:28:32.400)

theoretical physicist or anyone that thinks about the cosmos and saying that it's really the fact

Andrew Huberman (2:28:39.040)

that sometimes we'd say and do and think things and it feels so important. And then two days later,

Andrew Huberman (2:28:44.880)

like what happened? Well, you had a different brain processing algorithm entirely. You were in a

Andrew Huberman (2:28:51.680)

completely different state. And so what I want to do in this lifetime is I want to engage in as many

Andrew Huberman (2:28:59.680)

different levels of contraction and dilation of meaning as possible. I want to go to the micro.

Andrew Huberman (2:29:07.120)

I sometimes think about this. I'm like, if I just pulled over the side of the road, I bet you there's

Andrew Huberman (2:29:10.480)

an anthill there and their whole world is fascinating. You can't stay there. And you also

Andrew Huberman (2:29:15.760)

can't stay staring up at the clouds and just think about how we're just these little beings and it

Andrew Huberman (2:29:20.240)

doesn't matter. The key is the journey back and forth, up and down that staircase, back and forth

Lex Fridman (2:29:27.520)

and back and forth. And my goal is to get as many trips up and down that staircase as I can before

Andrew Huberman (2:29:32.240)

the reaper comes for me. Oh, beautiful. So the, the, the dance of dilation of meaning,

Andrew Huberman (2:29:36.960)

contraction between the different space, zoom in, zoom out, and get as many steps in on that

Andrew Huberman (2:29:44.240)

staircase. That's, that's my goal anyway. And I've watched people die. I watched my postdoc advisor

Andrew Huberman (2:29:50.160)

die wither away. My graduate, it was tragic, but they found beauty in these closing moments

Andrew Huberman (2:29:56.080)

because their bubble was their kids in one case, or like one of them was a Giants fan and like got

Andrew Huberman (2:30:03.040)

to see a Giants game, you know, in her last moments and like, and you just realize like it's a Giants

Andrew Huberman (2:30:08.400)

game, but not in that moment because time is closing. And so those time bins feel huge because

Andrew Huberman (2:30:13.040)

she's slicing things so differently. So I think, um, learning how to do that better and more fluidly,

Andrew Huberman (2:30:20.400)

recognizing where one is and not getting too taxed to the idea that there's one correct answer,

Andrew Huberman (2:30:27.280)

like that's what brings meaning. That's my goal anyway. I don't think there's a better way to end

Andrew Huberman (2:30:33.200)

it. Andrew, I really appreciate that you would, uh, come down and contract your space time and

Andrew Huberman (2:30:40.400)

focus on this conversation for a few hours. Uh, is a huge honor. I'm a huge fan of yours. As I told

Andrew Huberman (2:30:47.120)

you, I hope you keep growing and educating the world about the human mind. Thanks for talking

Andrew Huberman (2:30:53.680)

today. Thank you. I really appreciate the invitation to be here. And people might think I'm

Andrew Huberman (2:30:58.640)

saying it just cause I'm here, but I'm a huge fan of yours. I send your podcasts to my colleagues

Lex Fridman (2:31:02.960)

and other people. And I think what you're doing is, isn't just, uh, amazing. It's important. And

Lex Fridman (2:31:09.360)

so thank you. Thanks for listening to this conversation with Andrew Huberman. And thank

Andrew Huberman (2:31:14.800)

you to our sponsors, ASLEEP, a mattress that cools itself and gives me years of sleep.

Andrew Huberman (2:31:20.560)

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Andrew Huberman (2:31:27.040)

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Andrew Huberman (2:31:33.520)

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Andrew Huberman (2:31:39.600)

this podcast. If you enjoy this thing, subscribe on YouTube, review it with five stars on Apple

Andrew Huberman (2:31:44.800)

podcast, follow on Spotify, support on Patreon, or connect with me on Twitter at Lex Friedman.

Lex Fridman (2:31:51.520)

And now let me leave you with some words from Carl Jung. I am not what happened to me.

Andrew Huberman (2:31:58.320)

I am what I choose to become. Thank you for listening and hope to see you next time.

Andrew Huberman (30:03.680)

people in the labs are doing them, of course. And that work does tend to rely on insights

Andrew Huberman (30:10.080)

gained from having a very deep knowledge base where you can remember a paper or maybe a figure

Andrew Huberman (30:16.720)

in a paper, you could go look it up if you wanted to, but it's very different than the working

Andrew Huberman (30:20.720)

memory of the mathematician. And so when you're talking about coding or being in that tunnel of

Andrew Huberman (30:27.360)

thought and trying to iterate and keeping a lot of plates spinning, it speaks directly to working

Andrew Huberman (30:34.320)

memory. My lab hasn't done too much of that. But we are pushing working memory when we have people

Andrew Huberman (30:40.800)

do things like these simple lights out tasks. We can increase the cognitive load by increasing the

Andrew Huberman (30:47.440)

level of autonomic arousal to the point where they start doing less well. And everyone has a cliff.

Andrew Huberman (30:54.000)

This is what's kind of fun. We've had SEAL team operators come to the lab. We've had people from

Andrew Huberman (30:58.160)

other units in the military. We've had a range of intellects and backgrounds and all sorts of things

Lex Fridman (31:05.360)

and everyone has a cliff. And those cliffs sometimes show up as a function of the demands of

Andrew Huberman (31:12.160)

speed of processing or how many things you need to keep online. I mean, we're all limited at some

Andrew Huberman (31:18.480)

point in the number of things we can keep online. So what you're describing is very interesting

Andrew Huberman (31:21.760)

because I think it has to do with how narrow or broad the information set is. And I'm not an

Andrew Huberman (31:29.600)

active programmer, so this is a regime I don't really fully know. So I don't want to comment

Andrew Huberman (31:34.160)

about it in any way that doesn't suggest that. But I think that what you're talking about is

Andrew Huberman (31:41.920)

top down control. So this is prefrontal cortex keeping every bit of reflexive circuitry at bay,

Andrew Huberman (31:48.960)

the one that makes you want to get up and use the restroom, the one that makes you want to check

Andrew Huberman (31:51.840)

your phone, all of that, but also running these anterior thalamus to prefrontal cortex loops,

Andrew Huberman (31:59.040)

which we know are very important for working memory. Let me try to think through this a little

Andrew Huberman (32:04.240)

bit. So reducing the process of thinking to working memory access is tricky. It's probably

Andrew Huberman (32:14.640)

ultimately correct. But if I were to say some of the most challenging things that an engineer has

Andrew Huberman (32:23.440)

to do, and a scientific thinker, I would say it's kind of depressing to think that we do that best

Andrew Huberman (32:29.120)

in our 20s, but is this kind of first principles thinking step of saying you're accessing the

Andrew Huberman (32:39.600)

things that you know, and then saying, well, let me, how do I do this differently than I've done

Andrew Huberman (32:47.680)

it before? This weird like stepping back, like, is this right? Let's try it this other way. That's

Andrew Huberman (32:57.600)

the most mentally taxing step is like, you've gotten quite good at this particular pattern of

Lex Fridman (33:05.760)

how you solve this particular problem. So there's a pattern recognition first. You're like, okay,

Andrew Huberman (33:11.520)

I know how to build a thing that solves this particular problem in programming, say. And then

Andrew Huberman (33:18.400)

the question is, but can I do it much better? And I don't know if that's, I don't know what

Andrew Huberman (33:25.840)

the hell that is. I don't know if that's accessing working memory. That's almost access. Maybe it is

Andrew Huberman (33:32.480)

accessing memory in a sense. It's trying to find similar patterns in a totally different place that

Andrew Huberman (33:37.840)

it could be projected onto this. But you're not querying facts. You're querying like functional

Andrew Huberman (33:47.520)

things like. Yeah, it's patterns. I mean, you're running out, you're testing algorithms. Yeah.

Andrew Huberman (33:52.320)

Right. You're testing algorithms. So I want to just, because I know some of the people listening

Andrew Huberman (33:59.200)

to this and you have a basis in scientific training and have scientific training. So I

Andrew Huberman (34:04.560)

want to be clear. I think we can be correct about some things like the role of working memory in

Andrew Huberman (34:09.440)

these kinds of processes without being exhaustive. We're not saying they're the only thing. We can be

Andrew Huberman (34:14.160)

correct, but not assume that that's the only thing involved. And neuroscience, let's face it,

Andrew Huberman (34:20.000)

is still in its infancy. I mean, we probably know 1% of what there is to know about the brain.

Andrew Huberman (34:24.080)

I mean, we've learned so much and yet there may be global states that underlie this that

Andrew Huberman (34:30.480)

make prefrontal circuitry work differently than it would in a different regime or even time of day.

Andrew Huberman (34:37.040)

I mean, there's a lot of mysteries about this. So I just want to make sure that we're aiming for

Andrew Huberman (34:44.160)

precision and accuracy, but we're not going to be exhausted. So there's a difference there. And I

Andrew Huberman (34:49.440)

think sometimes in the vastness of the internet, that gets forgotten. So the other is that

Andrew Huberman (35:02.800)

we think about these operations at really focused, keeping a lot of things online.

Lex Fridman (35:09.040)

But what you were describing is actually, it speaks to the very real possibility probably

Andrew Huberman (35:16.400)

that with certainty, there's another element to all this, which is when you're trying out lots

Andrew Huberman (35:22.000)

of things, in particular, lots of different algorithms, you don't want to be in a state of

Andrew Huberman (35:27.680)

very high autonomic arousal. That's not what you want, because the higher level of autonomic

Andrew Huberman (35:32.080)

arousal and stress in the system, the more rigidly you're going to analyze space and time. And what

Andrew Huberman (35:38.080)

you're talking about is playing with space time dimensionality. And I want to be very clear. I'm

Andrew Huberman (35:43.200)

the son of a physicist. I am not a physicist. When I talk about space and time, I'm literally

Andrew Huberman (35:47.360)

talking about visual space and how long it takes for my finger to move from this point to this

Andrew Huberman (35:53.040)

point. You are facing a tiger and trying to figure out how to avoid being eaten by the tiger.

Lex Fridman (35:58.000)

And that's primarily going to be determined by the visual system in humans. We don't walk through

Andrew Huberman (36:02.720)

space, for instance, like a cent hound would and look at three dimensional scent plumes. When a

Andrew Huberman (36:09.040)

scent hound goes out in the environment, they have depth to the odor trails they're following.

Lex Fridman (36:15.280)

And they don't think about them. We don't think about odor trails. You might say,

Andrew Huberman (36:19.280)

oh, well, the smell's getting more intense. Aha. But they actually have three dimensional odor

Andrew Huberman (36:24.000)

trails. So they see a cone of odor, see, of course, with their nose, with their olfactory cortex.

Andrew Huberman (36:29.520)

We do that with our visual system. And we parse time, often subconsciously, mainly with our visual

Andrew Huberman (36:35.920)

system, also with our auditory system. And this shows up for the musicians out there. Metronomes

Andrew Huberman (36:40.160)

are a great way to play with this. Bass drumming, when the frequency of bass drumming changes,

Andrew Huberman (36:44.960)

your perception of time changes quite a lot. So in any event, space and time are linked

Andrew Huberman (36:50.240)

through the sensory apparatus, through the eyes and ears and nose, and probably through taste too,

Lex Fridman (36:55.280)

and through touch for us, but mainly through vision. So when you drop into some coding or

Lex Fridman (37:02.960)

iterating through a creative process or trying to solve something hard,

Andrew Huberman (37:08.960)

you can't really do that well if you're in a rigid, high level of autonomic arousal because

Andrew Huberman (37:15.280)

you're plugging in algorithms that are in this space regime, this time regime matches. It's

Andrew Huberman (37:20.880)

space time matched. Whereas creativity, I always think the lava lamp is actually a pretty good

Andrew Huberman (37:25.360)

example, even though it has these counterculture, new agey connotations, because you actually don't

Andrew Huberman (37:29.760)

know which direction things are going to change. And so in drowsy states, sleeping and drowsy

Andrew Huberman (37:36.320)

states, space and time become dislodged from one another somewhat, and they're very fluid.

Lex Fridman (37:41.040)

And I think that's why a lot of solutions come to people after sleep and naps. And this could

Andrew Huberman (37:47.440)

even take us into a discussion, if you like, about psychedelics and what we now know, for instance,

Andrew Huberman (37:53.040)

that people thought that psychedelics work by just creating spontaneous bursting of neurons

Lex Fridman (37:58.240)

and hallucinations. But the 5H2C and 2A receptors, which are the main sites for things like LSD and

Andrew Huberman (38:06.640)

psilocybin and some of the other ones that create hallucinations, the drugs that create hallucinations,

Andrew Huberman (38:13.600)

most of those receptors are actually in the collection of neurons that encase the thalamus,

Andrew Huberman (38:20.560)

which is where all the sensory information goes into, a structure called the thalamic

Andrew Huberman (38:24.320)

reticular nucleus. And it's an inhibitory structure that makes sure that when we're

Andrew Huberman (38:31.120)

sitting here talking, that I'm mainly focused on whatever I'm seeing visually, that I'm essentially

Andrew Huberman (38:36.880)

eliminating a lot of sensory information. Under conditions where people take psychedelics and

Andrew Huberman (38:41.600)

these particular serotonin receptors are activated, that inhibitory shell, it's literally shaped like

Andrew Huberman (38:48.240)

a shell, starts losing its ability to inhibit the passage of sensory information. But mostly

Andrew Huberman (38:55.440)

the effects of psychedelics are because the lateral connectivity in layer five of cortex

Andrew Huberman (39:00.800)

across cortical areas is increased. And what that does is that means that the space time relationship

Andrew Huberman (39:08.480)

for vision, like moving my finger from here to here, very rigid space time relationship,

Andrew Huberman (39:12.240)

right? If I slow it down, it's slower, obviously, but there's a prediction that can be made based on

Andrew Huberman (39:15.840)

the neurons in the retina and the cortex. On psychedelics, this could be a very strange

Andrew Huberman (39:19.520)

experience. But the auditory system has one that's slightly different space time, and they're matched

Andrew Huberman (39:25.920)

to one another in deeper circuits in the brain. The olfactory system has a different space time

Andrew Huberman (39:29.920)

relationship to it. So under conditions of these increased activation of these serotonin receptors,

Andrew Huberman (39:38.640)

space and time across sensory area starts being fluid. So I'm no longer running the algorithm for

Andrew Huberman (39:44.720)

moving my finger from here to here and making a prediction based on vision alone. I'm now,

Andrew Huberman (39:49.920)

this is where people talk about hearing sites, right? You start linking, this might actually

Andrew Huberman (39:57.280)

make a sound in a psychedelic state. Now I'm not suggesting people run out and do psychedelics

Andrew Huberman (40:01.120)

because it's very disorganized, but essentially what you're doing is you're mixing the algorithms.

Lex Fridman (40:05.600)

And so when you talk about being able to access new solutions, you don't need to rely on

Andrew Huberman (40:10.000)

psychedelics. If people choose to do that, that's their business. But in drowsy states, this lateral

Andrew Huberman (40:15.920)

connectivity is increased as well. The shell of the thalamus shuts down. And these are through

Andrew Huberman (40:21.440)

these so called pons chiniculate occipital waves. And what's happening is you're getting whole brain

Andrew Huberman (40:25.920)

activation at a level that you start mixing algorithms. And so sometimes I think solutions

Andrew Huberman (40:32.160)

come not from being in that narrow tunnel of space time and strong activation of working memory and

Andrew Huberman (40:38.720)

trying to well iterate if this, then this very strong, deductive and inductive thinking and

Andrew Huberman (40:43.920)

working from first principles, but also from states where something that was an algorithm

Andrew Huberman (40:49.920)

that you never had in existence before suddenly gets lumped with another algorithm. And all of a

Andrew Huberman (40:55.680)

sudden a new possibility comes to mind. And so space and time need to be fluid and space and

Andrew Huberman (41:03.280)

time need to be rigid in order to come up with something meaningful. And I realize I'm riffing

Andrew Huberman (41:08.160)

long on this, but this is why I think, you know, there was so much interest a few years ago with

Andrew Huberman (41:11.760)

Michael Pollan's book and other things happening about psychedelics as a pathway to exploration and

Andrew Huberman (41:17.760)

all this kind of thing. But the real question is what you export back from those experiences,

Andrew Huberman (41:21.920)

because dreams are amazing, but if you can't bring anything back from them, they're just amazing.

Andrew Huberman (41:27.200)

I wonder how to experiment with the mind without, without any medical assistance

Andrew Huberman (41:34.400)

first. Like, you know, I, I pushed my mind in all kinds of directions. I definitely want to,

Andrew Huberman (41:39.760)

I did, uh, shrooms a couple of times. I definitely want to, uh, figure out how I can experiment with,

Andrew Huberman (41:47.520)

um, with psychedelics. I'm talking to, uh, Rick Doblin, uh, soon. I even went back and forth. So

Andrew Huberman (41:57.040)

he does all these studies on psychedelics and he keeps ignoring the parts of my email that asks,

Andrew Huberman (42:02.240)

like, how do I participate in these studies? Well, there are some legality issues. I mean,

Andrew Huberman (42:06.160)

conversation, I want to be very clear. I'm not saying that anyone should go out and do psychedelics.

Andrew Huberman (42:09.920)

I think that drowsy states and sleep states are super interesting for accessing some of

Andrew Huberman (42:14.800)

these more creative states of mind. Hypnosis is something that my colleague, David Spiegel,

Andrew Huberman (42:19.200)

associate chair of psychiatry at Stanford works on where also, again, it's a unique state because

Andrew Huberman (42:24.000)

you have narrow context. So this is very, um, kind of tunnel vision and yet deeply relaxed,

Andrew Huberman (42:29.840)

excuse me, deeply relaxed where new algorithms, if you will, can start to surface, um, strong

Andrew Huberman (42:36.080)

state for inducing neuroplasticity. And I think, you know, so if I had a, um, I'm part of a group,

Andrew Huberman (42:43.040)

um, that, uh, it's called the liminal collective as a group of people that get together and talk

Andrew Huberman (42:47.840)

about, um, just wild ideas, but they try and implement. Um, and it's a, it's a really interesting

Andrew Huberman (42:53.680)

group. Some people from a military, from a logitech and some other backgrounds, academic

Andrew Huberman (42:58.800)

backgrounds. And I was asked, you know, what would be, um, if you could create a tool,

Andrew Huberman (43:03.280)

you just had a tool like your magic wand wish for the day, what would it be? I thought it'd

Andrew Huberman (43:07.520)

be really interesting if someone could develop psychedelics that have, um, on off switches.

Lex Fridman (43:14.960)

So you could go into a psychedelic state very deeply for 10 minutes, but you could launch

Andrew Huberman (43:22.160)

yourself out of that state and place yourself into a linear real world state very quickly

Lex Fridman (43:27.040)

so that you could extract whatever it was that happened in that experience. And then go back

Andrew Huberman (43:30.960)

in if you wanted, because the problem with psychedelic states and dream states is that

Andrew Huberman (43:37.120)

first of all, a lot of the reason people do them is they're lying. They say they want plasticity

Lex Fridman (43:42.080)

and they want all this stuff. They want a peak experience inside of an amplified experience.

Lex Fridman (43:47.760)

So they're kind of seeking something unusual. And I think we should just be honest about that

Andrew Huberman (43:51.680)

because a lot of times they're not trying to make their brain better. They're just trying

Andrew Huberman (43:54.400)

to experience something really amazing. But the problem is space and time are so unlocked

Andrew Huberman (44:01.920)

in these states, just like they are in dreams, that you can really end up with a whole lot of

Andrew Huberman (44:06.400)

nothing. You can have an amazing amplified experience housed in an amplified experience

Lex Fridman (44:12.320)

and come out of that thinking you had a meaningful experience when you didn't bring anything back.

Andrew Huberman (44:18.640)

You didn't bring anything back. All you have is a fuzzy memory of having a transformational

Andrew Huberman (44:24.560)

experience, but you don't actually have tools to bring back, sorry, actually concrete ideas to

Andrew Huberman (44:32.080)

bring back. Yeah, it's interesting. I wonder if it's possible to do that with a mind to be able to

Andrew Huberman (44:38.960)

hop back and forth. I think that's where the real power of adjusting states is going to be. It

Andrew Huberman (44:45.440)

probably will be with devices. I mean, maybe it will be done through pharmacology. It's just that

Andrew Huberman (44:50.000)

it's hard to do on off switches in human pharmacology that we have them for animals.

Andrew Huberman (44:54.320)

I mean, we have Cree flip recombinases and we have channel opsins and halo root opsins and

Andrew Huberman (45:02.080)

all these kinds of things. But to do that work in humans is tricky, but I think you could do it

Andrew Huberman (45:07.200)

with virtual reality, augmented reality and other devices that bring more of the somatic experience

Andrew Huberman (45:12.880)

into it. You're of course, a scientist who's studying humans as a collective. I tend to be

Andrew Huberman (45:19.440)

just a one person scientist of just looking at myself and I play when these deep thinking,

Andrew Huberman (45:27.120)

deep work sessions, I'm very cognizant in the morning that there's times when my mind is so

Andrew Huberman (45:34.880)

eloquent at being able to jump around from ideas and hold them all together. I'm almost like I

Andrew Huberman (45:43.440)

step back from a third person perspective and enjoy that, whatever that mind is doing,

Andrew Huberman (45:49.600)

I do not waste those moments. I'm very conscious of this little creature that woke up that's only

Andrew Huberman (45:59.280)

awake for, if we're being honest, maybe a couple hours a day. Early part of the day for you.

Andrew Huberman (46:04.960)

Early part of the day. Not always. Well, early part of the day for me is a very fluid concept.

Andrew Huberman (46:11.520)

You're one of those.

Lex Fridman (46:12.320)

Yeah, I'm one.

Andrew Huberman (46:12.800)

Yeah, you're one of those.

Andrew Huberman (46:13.680)

Being single, one of the problems, single and no meetings. I don't schedule any meetings.

Andrew Huberman (46:20.000)

I've been living at like a 28 hour day. So it drifts. So it's all over the place. But

Andrew Huberman (46:28.720)

after a traditionally defined full night's sleep, whatever the heck that means, I find that in those

Andrew Huberman (46:38.000)

moments, there's a clarity of mind that's just, everything is effortless. And it's the deepest

Andrew Huberman (46:44.960)

dives intellectually that I make. And I'm cognizant of it. And I try to bring that to the other parts

Andrew Huberman (46:52.720)

of the day that don't have it and treasure them even more in those moments because they only last

Andrew Huberman (46:57.840)

like five or 10 minutes. Because of course, in those moments you want to do all kinds of stupid

Andrew Huberman (47:02.640)

stuff that are completely is worthless, like check social media or something like that.

Lex Fridman (47:07.360)

But those are the most precious things in intellectual life is those mental moments

Andrew Huberman (47:15.040)

of clarity. And I wonder, I'm learning how to control them. I think caffeine is somehow involved.

Lex Fridman (47:21.360)

I'm not sure exactly.

Andrew Huberman (47:22.160)

Sure. Well, because if you learn how to titrate caffeine,

Lex Fridman (47:25.120)

and everyone's slightly different with this, what they need, but if you learn to titrate caffeine

Andrew Huberman (47:29.440)

with time of day and the kind of work that you're trying to do, you can bring that autonomic arousal

Andrew Huberman (47:33.440)

state into a close to perfect place. And then you can tune it in with, sometimes people want a little

Andrew Huberman (47:39.360)

bit of background music. Sometimes they want less, these kinds of things. The early part of the day

Andrew Huberman (47:43.840)

is interesting because the one thing that's not often discussed is this transition out of sleep.

Lex Fridman (47:48.800)

So there's a book, I think it's called Winston Churchill's Nap. And it's about

Andrew Huberman (47:53.680)

naps and the transition between wake and sleep as a valuable period. A long time ago,

Andrew Huberman (48:02.320)

someone who I respect a lot was mentoring me said, be very careful about bringing in

Andrew Huberman (48:08.720)

someone else's sensory experience early in the day. So when I wake up, I'm very drowsy. I sleep

Andrew Huberman (48:14.800)

well, but I don't emerge from that very quickly. I need a lot of caffeine to wake up and whatnot.

Lex Fridman (48:20.400)

But there's this concept of getting the download from sleep, which is in sleep, you were essentially

Andrew Huberman (48:28.080)

expunging the things that you don't need, the stuff that is meaningless from the previous day,

Lex Fridman (48:32.960)

but you were also running variations on these algorithms of whatever it is you're trying to

Andrew Huberman (48:36.880)

work out in life on short timescales like the previous day and long timescales like your whole

Andrew Huberman (48:41.520)

life. And those lateral connections in layer five of the neocortex are very robustly active and

Andrew Huberman (48:51.040)

across sensory areas. And you're running an algorithm or it's a brain state that will be

Andrew Huberman (48:56.320)

useless in waking. You wouldn't get anything done. You'd be the person talking to yourself

Andrew Huberman (49:00.320)

in the hallway or something about something that no one else can see. But in those states,

Andrew Huberman (49:06.400)

the theory is that you arrive at certain solutions and those solutions will reveal

Andrew Huberman (49:10.640)

themselves in the early part of the day, unless you interfere with them by bringing in,

Lex Fridman (49:16.160)

social media is a good example of you immediately enter somebody else's

Andrew Huberman (49:20.400)

space time sensory relationship. Someone is the conductor of your thoughts in that case.

Lex Fridman (49:25.200)

And so many people have written about this. What I'm saying isn't entirely new, but allowing the

Andrew Huberman (49:30.720)

download to occur in the early part of the day and asking the question, am I more in my head

Andrew Huberman (49:38.240)

or am I more of an interoceptive or exteroceptive mode? And depending on the kind of work you need

Andrew Huberman (49:43.600)

to do, if it sounds like for you, it's very interoceptive and you've got a lot of thinking

Andrew Huberman (49:50.000)

going on and a lot of computing going on, allowing yourself to transition out of that sleep state and

Andrew Huberman (49:54.880)

arrive with those solutions from sleep and plug into the work really deeply. And only then allowing

Andrew Huberman (50:01.520)

things like music, news, social media, doesn't mean you shouldn't talk to loved ones and see

Andrew Huberman (50:06.240)

faces and things like that. But some people have taken this to the extreme. When I was a graduate

Andrew Huberman (50:09.840)

student at Berkeley, there was a guy there, a professor, brilliant, odd, but brilliant,

Andrew Huberman (50:16.960)

who was so fixated on this concept that he wouldn't look at faces in the early part of the

Andrew Huberman (50:21.920)

day because he just didn't want anything else to impact him. Now he didn't have the most rounded

Andrew Huberman (50:29.920)

life, I suppose. But if you're talking about cognitive performance, this could actually be

Andrew Huberman (50:35.200)

very beneficial. You said so many brilliant things. So one, if you read books that describe

Andrew Huberman (50:41.840)

the habits of brilliant people like writers, they do control that sensory experience in the

Andrew Huberman (50:51.200)

hours after wake. Like many writers, you know, they have a particular habit of several hours

Andrew Huberman (50:58.000)

early in the morning of actual writing. They don't do anything else for the rest of the day,

Lex Fridman (51:02.320)

but they control, they're very sensitive to noises and so on. I think they make it very difficult to

Andrew Huberman (51:07.200)

live with them. I try to, I'm definitely like that. Like I could, I love to control the sensory

Lex Fridman (51:16.000)

how much information is coming in. There's something about the peaceful, just everything

Andrew Huberman (51:20.560)

being peaceful. At the same time, and we were talking to a mutual friend of Whitney Cummings,

Andrew Huberman (51:26.720)

who has a mansion, a castle on top of a cliff in the middle of nowhere. She actually purchased her

Andrew Huberman (51:34.240)

own island. She wants silence. She wants to control how much sound is coming in.

Andrew Huberman (51:41.680)

She's very sensitive to sound and environment. Beautiful home and environment, but like clearly

Andrew Huberman (51:46.560)

puts a lot of attention into details. Yeah. And very creative.

Andrew Huberman (51:51.920)

Yeah. And that's, yeah, that allows for creativity to flourish. I'm also, I don't like that feels

Andrew Huberman (51:58.480)

like a slippery slope. So I enjoy introducing the noises and signals and training my mind to

Andrew Huberman (52:07.360)

be able to tune them out. Cause I feel like you can't always control the environment so perfectly

Andrew Huberman (52:12.960)

because, cause your mind gets comfortable with that. I think it's a skill that you want to learn

Andrew Huberman (52:17.840)

to be able to shut it off. Like I often go to like back before COVID to a coffee shop.

Andrew Huberman (52:23.840)

It really annoys me when there's sounds and voices and so on, but I feel like I can train my mind

Lex Fridman (52:29.200)

to, to block them out. So it's, it's a balance, I think.

Andrew Huberman (52:32.560)

Yeah. And I think you know, two things come to mind as you're saying this first of all,

Andrew Huberman (52:37.760)

yeah. I mean, we're talking about what's best for work is not always what's best for, you know,

Andrew Huberman (52:42.960)

completeness of life. I mean, you know, autism is probably many things like when you hit autism,

Andrew Huberman (52:47.600)

just like feet, there are probably 50 ways to get a fever. There are probably 50 ways to,

Andrew Huberman (52:52.080)

that the brain can create what looks like autism or what people call autism.

Andrew Huberman (52:55.760)

There's an interesting set of studies that have come out of David Ginty's lab at Harvard med,

Andrew Huberman (53:02.240)

looking at these are mouse mutants where these are models for autism, where nothing is disrupted

Andrew Huberman (53:09.040)

in the brain proper and in the central nervous system, but the sensory app, the sensory neurons,

Andrew Huberman (53:15.040)

the ones that innervate the skin and the ears and everything are, are hypersensitive. And this maps

Andrew Huberman (53:19.680)

to a mutation in certain forms of human autism. So this means that the, the overload of sensory

Andrew Huberman (53:27.840)

information and sensory experience that a lot of autistics feel, they're like that they can't

Andrew Huberman (53:31.680)

tolerate things. And then they get the stereotype behaviors, the rocking and the kind of the

Andrew Huberman (53:35.520)

shouting it, you know, we always thought of that as a brain problem. In some cases it might be,

Lex Fridman (53:41.520)

but in many cases it's because they just can't, they, they seem to have a, it's like turning the

Andrew Huberman (53:46.640)

volume up on every sense. And so they're overwhelmed and none of us want to become like

Andrew Huberman (53:51.040)

that. I think it's very hard for them and it's hard for their parents and so forth. So I, I like

Andrew Huberman (53:55.360)

the coffee shop example because the way I think about trying to build up resilience, you know,

Andrew Huberman (54:02.960)

physically or mentally or otherwise is one of I guess we could call it limb. I like to call it

Andrew Huberman (54:07.040)

limbic friction. That's not a real scientific term. And I acknowledge that I'm making it up

Andrew Huberman (54:10.880)

now because I think it captures the concept, which is that, you know, we always hear about

Andrew Huberman (54:14.880)

resilience. It makes it sound like, oh, you know, under stress where everything's coming at you,

Andrew Huberman (54:18.640)

you're going to stay calm, but there's another, you know, so limbic, the limbic system wants to

Andrew Huberman (54:23.760)

pull you in some direction, typically in the direction of reflexive behavior and the prefrontal

Andrew Huberman (54:30.240)

cortex through top down mechanisms has to suppress that and say, no, we're not going to respond to

Andrew Huberman (54:35.920)

the banging of the coffee cups behind me, or I'm going to keep focusing. That's pure top down

Andrew Huberman (54:41.040)

control. So limbic friction is high in that environment. You've put yourself into a high

Andrew Huberman (54:45.920)

limbic friction environment, meaning that the prefrontal cortex has to work really hard.

Lex Fridman (54:49.600)

But there's another side to limbic friction too, which is when you're very sleepy,

Andrew Huberman (54:54.320)

there's nothing incoming. It can be completely silent and it's hard to engage and focus because

Andrew Huberman (54:59.440)

you're drifting off and you're getting sleepy. So their limbic friction is high, but for the

Andrew Huberman (55:03.120)

opposite reason, autonomic arousal is too low. So they're turning on Netflix in the background or

Andrew Huberman (55:08.320)

looping a song might boost your level of alertness that will allow top down control to be in exactly

Andrew Huberman (55:15.280)

the sweet spot you want it. So this is why earlier I was saying it's all about how we feel inside

Andrew Huberman (55:21.200)

relative to what's going on on the outside. We're constantly in this, I guess one way you

Andrew Huberman (55:26.480)

could envision it spatially, especially if people are listening to this just on audio,

Andrew Huberman (55:31.760)

is I like to think about it kind of like a glass barbell where one sphere of perception and

Andrew Huberman (55:37.360)

attention can be on what's going on with me. And one sphere of attention can be on what's going on

Andrew Huberman (55:42.480)

with you or something else in the room or in my environment. But this barbell isn't rigid. It's

Andrew Huberman (55:48.000)

not really glass. Would plasma work here? I don't know anything about plasma. Sorry. I don't know.

Lex Fridman (55:55.360)

So imagine that this thing can contort the size of the globes at the end of this barbell can get

Andrew Huberman (56:00.320)

bigger or smaller. So let's say I close my eyes and I bring all my experience into what's going on

Andrew Huberman (56:06.800)

through interoception internally. Now it's as if I've got two orbs of perception just on my

Andrew Huberman (56:12.240)

internal state, but I can also do the opposite and bring both orbs of perception outside me.

Andrew Huberman (56:17.040)

I'm not thinking about my heart rate or my breathing. I'm just thinking about something

Andrew Huberman (56:20.320)

I see. And what you'll start to realize as you kind of use this spatial model is that two things.

Andrew Huberman (56:27.040)

One is that it's very dynamic and that the more relaxed we are, the more these two orbs of

Andrew Huberman (56:34.400)

attention, the two ends of the barbell can move around freely. The more alert we are,

Andrew Huberman (56:40.320)

the more rigid they're going to be tethered in place. And that was designed so that if I have

Andrew Huberman (56:45.040)

a threat in my environment, it's tethered to that threat. If something's coming to attack me, I'm not

Lex Fridman (56:50.880)

going to be like, oh, my breathing cadence is a little bit quick. That's not how it works. Why?

Andrew Huberman (56:54.480)

Because both orbs are linked to that threat. And so my behavior is now actually being driven by

Andrew Huberman (57:01.680)

something external, even though I think it's internal. And so I don't want to get too abstract

Andrew Huberman (57:05.600)

here because I'm a neuroscientist. I'm not a theorist. But when you start thinking about

Andrew Huberman (57:10.720)

models of how the brain works, there are only really three things that neurons do. They're

Andrew Huberman (57:15.360)

either sensory neurons, they're motor neurons, or they're modulating things. And the models of

Andrew Huberman (57:22.720)

attention and perception that we have now, 2020, tell us that we've got interoception

Lex Fridman (57:28.720)

and exteroception. They're strongly modulated by levels of autonomic arousal. And that if we want

Andrew Huberman (57:33.440)

to form the optimal relationship to some task or some pressure or some thing, whether or not it's

Andrew Huberman (57:40.320)

sleep, an impending threat, or coding, we need to adjust our internal space time relationship with

Andrew Huberman (57:47.600)

the external space time relationship. And I realize I'm repeating what I said earlier.

Lex Fridman (57:51.520)

But we can actually assign circuitry to this stuff. It mostly has to do with how much limbic

Andrew Huberman (57:56.880)

friction there is, how much you're being pulled to some source. That source could be internal.

Andrew Huberman (58:01.680)

If I have pain, physical pain in my body, I'm going to be much more interoceptive than I am

Andrew Huberman (58:06.640)

exteroceptive. You could be talking to me and I'm just going to be thinking about that pain. It's

Andrew Huberman (58:09.840)

very hard. And the other thing that we can link it to is top down control, meaning anything in

Andrew Huberman (58:17.280)

our environment that has a lot of salience will tend to bring us into more exteroception than

Andrew Huberman (58:21.600)

interoception. And again, I don't want to litter the conversation with just a bunch of terms, but

Lex Fridman (58:26.880)

what I think it can be useful for people is to do what essentially you've done,

Andrew Huberman (58:31.280)

Lex, is to start developing an awareness. When I wake up, am I mostly in a mode of interoception

Andrew Huberman (58:37.200)

or exteroception? When I work well, what does working well look like from the perspective of

Andrew Huberman (58:43.760)

autonomic arousal? How alert or calm am I? What kind of balance between internal focus and external

Andrew Huberman (58:49.520)

focus is there? And to sort of watch this process throughout the day. Can you linger just briefly

Andrew Huberman (58:54.800)

on, because you use this term a lot and it'd be nice to try to get a little more color to it,

Andrew Huberman (59:00.400)

which is interoception and exteroception. What are we exactly talking about? So like

Andrew Huberman (59:07.280)

what's included in each category and how much overlap is there? Interoception would be an

Andrew Huberman (59:14.560)

awareness of anything that's within the confines or on the surface of my skin that I'm sensing.

Lex Fridman (59:20.320)

So literally physiological. Physiologically, like within the boundaries of my skin

Lex Fridman (59:24.480)

and probably touched to the skin as well. Exteroception would be perception of anything

Andrew Huberman (59:30.080)

that's beyond the reach of my skin. So that bottle of water, a scent, a sound, and this

Andrew Huberman (59:40.800)

can change dramatically actually. If you have headphones in, you tend to hear things in your

Andrew Huberman (59:44.320)

head as opposed to a speaker in the room. This is actually the basis of ventriloquism.

Lex Fridman (59:49.440)

So there are beautiful experiments done by Greg Reckenzone up at UC Davis, looking at how auditory

Lex Fridman (59:55.040)

and visual cues are matched and you have an array of speakers and this will become obvious as I say