The Biology of Social Interactions & Emotions | Dr. Kay Tye

Welcome to the Huberman Lab Podcast where we discuss science and science based tools for everyday life. I'm Andrew Huberman and I'm a Professor of Neurobiology and Ophthalmology at Stanford School of Medicine. My guest today is Dr. K. Tai. Dr. K. Tai is a Professor of Neuroscience at the Salk Institute for Biological Studies. She did her training at MIT and at Stanford and is currently an investigator with the Howard Hughes Medical Institute, which is a highly curated group of individuals who are incentivized to do high risk, high reward work and pioneer new areas of biological study. Throughout her career, Dr. Ktai has made fundamental breakthroughs into our understanding of the brain, including demonstrating that a brain area called the amygdala, which most people associate with fear and threat detection, is actually involved in reinforcement of behaviors and experiences that are positive and involve reward. Her current work focuses on various aspects of social interaction, including what happens when we feel lonely or isolated. Indeed, today K. Tai will tell us about her discovery of so called loneliness neurons, neurons that give us that sense that we are not being fulfilled from our social interactions. She also describes a phenomenon she discovered called social homeostasis, which is our sense that we are experiencing enough to not enough or just enough social interaction, irrespective of whether or not we are an introvert or an extrovert. We also talk about social hierarchies and social rank, how people and animals tear out into so called alphas and betas, subordinates and dominance, et cetera, in all sorts of social interactions. I think everyone will find that discussion especially interesting, and we talk about the role of social media and online interactions and why, despite extensive interaction with many, many individuals, those social, social media and online interactions can often leave us feeling deprived in specific ways. We talk about the neurochemical, the neural circuit, and some of the hormonal aspects of social interactions. It's a discussion that by the end will have you thinking far more deeply about what is a social interaction and why certain social interactions leave us feeling so good, others feeling sort of meh, and why other social interactions or lack of social interactions can often leave us feeling quite depleted, even depressed. It's a conversation central to mental illness and the understanding of things like depression and anxiety, PTSD and isolation. And it's a conversation central to mental health and in order to build healthy social interactions before we begin, I'd like to emphasize that this podcast is separate from my teaching and research roles at Stanford. It is, however, part of my desire and effort to bring zero cost to consumer information about science and science related tools to the general public. In keeping with that theme, I'd like to thank the sponsors of today's podcast. Our first sponsor is eight Sleep. Eight Sleep makes smart mattress covers with cooling, heating and sleep tracking capacity. I've spoken many times before on this and other podcasts about the fact that sleep is the foundation of mental health, physical health and performance. Now, one of the key aspects to getting a great night's sleep is to control the temperature of your sleeping environment. And that's because in order to fall and stay deeply asleep, your body temperature actually has to drop by about 1 to 3 degrees. And in order to wake up in the morning feeling refreshed, your body temperature actually has to increase by about 1 to 3 degrees. 8 Sleep makes it extremely easy to control the temperature of your sleeping environment at the beginning, middle and throughout the night and when you wake up in the morning. I've been sleeping on an eight Sleep mattress cover for nearly three years now and it has dramatically improved my sleep. If you'd like to try Eight Sleep, you can go to eightsleep.comhuberman to save $150 off their Pod 3 cover. Eight Sleep currently ships to the USA, Canada, UK, select countries in the EU and Australia. Eight Sleep.comhuberman Today's episode is also brought to us by Levels. Levels is a program that lets you see how different foods and different activities and your sleep patterns impact your health by giving you real time feedback on your diet using a continuous glucose monitor. Now, blood glucose, sometimes referred to as blood sugar, has an immediate and long term impact on your energy levels and your overall health. One of the best ways to maintain focus and energy throughout your day as well as to keep your so called metabolic health in best order is to make sure that your blood glucose never spikes too much nor does it get too low. With levels, you can monitor how different foods and food combinations impact your blood glucose levels on a moment to moment basis. I've been using levels for some time now and it's really helped me understand which foods and food combinations, exercise schedules and sleep schedules are optimal for my blood glucose levels and how that translates to energy levels and other metrics of health. If you're interested in learning more about levels and trying a continuous glucose monitor, you can go to Levels Link Huberman Levels has just launched a new CGM sensor that is smaller and has even better tracking than before. Right now they're also offering two free months of membership. Again, that's levels.link l I n K Slash Huberman to try the new Sensor and two free months of membership. Today's episode is also brought to us by Element. Element is an electrolyte drink that has everything you need and nothing you don't. That means zero sugar and the appropriate ratios of the electrolytes, sodium, magnesium and potassium. And that correct ratio of electrolytes is extremely important because every cell in your body, but especially your nerve cells, your neurons, relies on electrolytes in order to function properly. So when you're well hydrated and your hydration also includes the appropriate ratios of electrolytes, your mental functioning and your physical functioning is improved. I drink one packet of element dissolved in about 16-32oz of water when I wake up in the morning as well as while I exercise. And if I sweat a lot during that exercise, I often will. A third element packet dissolved in about 32 ounces of water after I exercise. Element comes in a variety of different flavors. Personally, I like all the fruit flavors, so raspberry and watermelon are my favorite. I also like the citrus flavored one. Frankly, I can't really pick just one of the fruit flavors. I like them all so much. And it also comes in chocolate and chocolate mint flavors which I find are best in the winter months because of course you don't just need hydration on hot days and in the summer and spring months, but also in the winter when the temperatures are cold and the environment tends to be dry. If you'd like to try Element, you can go to drink element spelled lmnt.comhuberman to try a free sample pack again, that's drinkelement.comhuberman and now for my conversation with Dr. K. Tai. Dr. K. Tai, welcome Andy Huberman.

What a treat.

Folks are going to hear you call me Andy and wonder if my name is Andy. I always know who I'm speaking to according to whether or not they call me Andrew, which is my family and people that I know after a certain period of my life. Drew, which are people that know me through my very brief and non illustrious career in boxing. And Andy, which are people that met me as I was coming up through science. Let's just put it this way, there was another Andrew. We did a coin flip and I lost. So Andy is fine, Andrew's fine. Whatever makes you comfortable. What's important today is not how anyone refers to me, but rather the discussion about your work, which is spectacular. I've known you a long time and I've been following your career and it's just been amazing and wonderful to see the contributions you've made to science and also to the culture of science. So we're going to talk about both of those things. To kick things off, let's talk about a brain structure that most people, I think, have heard of, but that is badly misunderstood, and that's the amygdala. Most people hear amygdala and they think, oh, fear, that's what the amygdala is all about. But, you know, and I'm hoping you'll educate us on the fact that the amygdala is actually far more complex than that and far more interesting than that. So when you hear the word amygdala, where does your mind go?

I agree that a lot of the bandwidth on the amygdala has been occupied by fear studies. But we've known actually for a really long time that the amygdala is important for all sorts of emotional processing. Since Kluver and Bucy performed lesions on monkeys and found that monkeys would then have flat affective responses to all sorts of different stimuli. Poop, food, inanimate object, whatever. It was just nothing. No emotion, no emotional response, no motivational significance, however you want to phrase it, to things that usually would make you either, you know, disgusted or excited or neutral. And so I think that that knowledge about the amygdala was there from the beginning. It's not something I came up with, but then it's interesting. It's almost a meta statement or a meta observation about how scientific research progresses. Sometimes you make a lot of progress in one particular vein because it's easy to press forward there. But it's important to also think about all the other parts and filling in the space in between to make sure you haven't missed anything. So the narrative about the amygdala became about fear. And I think also just when we think about survival, when you are an animal in the natural world, especially if you're a prey animal, which is the majority, you know, that's a lot of animals, then you need to prioritize escaping a predator. It's immediate threat on your survival versus rewards. Mating, drinking water, getting food. These things can be done later. Escaping this predator is paramount. And so there should be some natural asymmetry in how we process emotion at baseline. And so that's something that we've looked into a lot as well. But I think the big picture discovery that my team has contributed to our understanding of the amygdala is that it represents a fork in the road for processing emotional valence and thinking about all these old psychological theories about how do you emotionally evaluate the world around you? What's. What's the chain of events? Is there a chain of events? What's happening in a certain order versus what's happening in parallel? For example, one model is there's all this information that comes in, and then we have to filter out what's important. What's going to be something that I need to pay attention to versus what do I need to ignore. If I'm driving, I need to pay attention to the road. This light, this pedestrian just started walking versus what it feels like for my sock to be touching my foot. Not super relevant right now. Or my butt against the seat. Nothing I need to pay attention to. I need to focus on the dynamic information. Then you have to select. The second step would be selecting whether it's good or bad and what you want to do with it. And so that process, I think the selection of whether you're assigning it a positive or negative valence happens in the amygdala.

So glad you brought up this word valence. I think it's a word that some scientists, but most of the general public are probably not familiar with. So let's talk about valence. And then I want to go back to the amygdala and kind of explore some of its diversity of function a little bit more. So when I hear the word valence, I think goodness versus badness of something is that basically.

Basically it's been used in a lot of different fields, I think of that negative and positive numbers. But it's an analogy that we take to just mean, yeah, net positive, net negative. And it's an intentional departure from the word value. Value becomes very scalar. Everything's on. You know, it can be in the same direction with different magnitudes, is often how we think about value. It could be representing both valences, but often it's a small reward and a big reward or small punishment. And a big punishment is how experimentally we parse value. And so valence is just asking about how your brain responds to things that are good or bad. What are neurons that might respond similarly to things that are good and bad? Those might be importance neurons rather than positive or negative valence neurons. So, yeah, I think it's just a term that signifies that next step.

So when we walk into, say, a novel environment, do you think that our amygdalas are active and really trying to figure out whether or not an environment, a set of people, or a person is safe? And really just check that box first in order to be able to do Other things is this business of determining valence and the role of the amygdala in that kind of the first gate that we have to walk through anytime we're in a new environment. For instance, you showed up here today and you mentioned, I think I locked my car. And I said, you'll be fine in this neighborhood either way. And then you walked in and presumably you were taking in the new environment, meeting some new people. We had a little discussion about caffeine, a little discussion about alcohol. And presumably because you and I know one another, you felt safe. I would hope so. But presumably the amygdala is always performing this role. Even if we have some prior knowledge about something, just figuring out, am I safe here? Where are the exits? Where are the entrances? Who's here? What's their story? Do you think all of that is operating? And do you think it's always conscious or is it largely unconscious to us?

Okay, so there's a few different questions there. First, I want to address the question about novelty, and then I want to come back to the other issue of conscious. But the way the amygdala works is its job is to assign meaning to anything that could have motivational significance. And so if it's a brand new thing, we're paying attention, we're seeing if it mattered, did it matter? And so I think anything that's novel, even if we don't know what it means, a loud sound you've never heard before, even if it signifies nothing of motivational significance, the first few times that you're presented with it, you'll get an amygdala response. So you see this in the lab, play the tone for the first time, and then there's a response that rapidly decays when the tone doesn't end up predicting anything that the animal can detect or human.

Is this also true in humans?

Yes, this is true in humans. If you're the type of person that puts your phone on do not disturb versus has it on vibrate, and, you know, sometimes it's always vibrating and it's just. It vibrates all the time. Whereas I put my phone on do not disturb. And so when someone else's phone rings, it's very startling to me, but they don't even notice because that's just the sound their phone makes. It makes it all the time. So I think it has to do with how many times you're presented with it. And it's a startle response. So the first few times that you are presented with a stimulus, the amygdala will respond and then it decays very quickly. And then only if that stimulus predicts something important, something rewarding or punishing, then will it begin to respond again. So it's like you're giving everything novel a chance to tell you in one trial, in single trial learning, if something's going to happen. And so I think a fire alarm is a great example. Fire alarm goes off your instantly, you're looking around, is there anything happening, even just people rushing out? There's the salient thing that you're going to respond to. And if you have a lot of fire drills, then you might respond differently after a while. So I think that's the habituation component.

You mentioned that the amygdala will respond to a novel stimulus and if it predicts something interesting, then other things happen, we'll talk about those. If not, the amygdala stops responding. And you said something really important, which is that the amygdala will respond to something that is predicting reward or punishment. And I think most people don't realize that. In fact, I think a lot of early career neurobiologists don't realize that, that the amygdala is not just involved in fear and punishment. So when we talk about the amygdala, presumably we're talking about the amygdala complex, a bunch of other things. So is it true that there are neurons in the amygdala complex that predict reward and others that predict fear and punishment?

Yeah. So as a graduate student, I worked on a part of the amygdala called the basolateral amygdala. It's still a complex within the broader amygdala. This brain region is cortical, like in that it's mostly glutamatergic neurons with some GABAergic neurons mixed in, but without the same structure that the cortex has. And I studied the amygdala in the context of reward. I found essentially that when you induce plasticity, you get a synaptic strengthening. When animals learn things, amygdala neurons fire in response to cues that predict rewards. And this was coming into the context of a field that had shown that this happens with fear. And so this became. I remember the very first time I gave a presentation at a scientific conference. I was a junior graduate student. I was given a 10 minute talk at the inaugural Amygdala Gordon Research Conference. Many famous professors were speaking and there were two talks about the amygdala and reward. And I was one of them. And the response to the talk was just how is this Possible. How can the amygdala. How can you get the same readout for reward and fear? And really, it came to be. There's two possibilities. I mean, there's more possibilities, but the main two possibilities are, number one, that the amygdala wasn't specific for fear at all. It just responds to anything important. If it's important, it responds, period. The other possibility is that the amygdala is sending. Has different neurons that respond to positive and negative predictive stimuli and sends this information to different downstream targets to respond differently. Obviously, I respond differently to a reward. I walk towards it, I consume it, a punishment. I'm avoiding it. And so clearly the behaviors are diametrically opposed. And so to me, it seemed very possible, at least that there was a divergence point and maybe this could be it. And so we just did some very simple experiments when I first started my lab to trace the projection targets of amygdala neurons and record. And so everything's all mixed up together. So it's not obvious that they would. That this would be a fork in the road, but when you look at them, you do see that there are projections that come from the amygdala that are predominantly encoding either reward or fear. And there's many different projections. And, you know, this is just the beginning. But this was a time when it was a novel concept to even think that neurons from one region could have completely different functions going to different downstream targets, which now seems totally obvious, and there's hundreds and hundreds of papers showing it now. But at the time, it was difficult to get this work published because that's just not how people thought about information moving through the brain, I guess.

Well, I think, first of all, such important work and so wonderful to be early in the phase of recasting how the brain works, which is what you did. I think most people in the general public still think amygdala fear, and clearly it's able to signal reward and punishment, as you discovered and are now pointing out. I'm curious, does the amygdala have a direct line to some of the organs of the body that can change our bodily activation state, heart rate, breathing rate, muscle tension. Because I think most of us experience fear and reward as both in our head, in our brains, but also of the body.

Great question, Great question. So I'll tell you the clues that lead me to my current working model, which may, you know, is not necessarily the final word, but I would say that I think the amygdala complex, as we're discussing it, these 13 subnuclei that reside in the temporal lobe. They are important for assigning importance, but they're not important for producing the actual autonomic arousal that we associate with panic or fear. The reason I say this is there's a famous case study, patient Smoke, who has bilateral damage to her amygdalae and no responses to emotional faces, no responses to fearful stimuli, but capable of having the panic response due to low to suffocation associated with suffocation. And so there's still the ability to produce that panic and arousal response. It's just not the cognitive evaluation of it. I think that's what we think the amygdala is doing, is assigning that it does receive information from the rest of the body. There are, for example, ghrelin receptors in the amygdala, things that can sense hunger. And we've done some work looking at this, kind of inspired by. I'm not sure if you're familiar with this study. It's a controversial study, Danziger, 2011, but where the Supreme Court judges, they looked at Supreme Court judge rulings on parole decisions across the day relative to meal breaks. And you could see right after it's like breakfast, 90%, everybody's getting parole, everybody's getting out. Yeah. And then it just drops till 10%, then there's lunch, then we're back to 80%. And then it just precipitously drops to single digits again.

So the judges are changing the leniency of their rulings depending on how well fed they are.

You know, there are counterarguments to this, but that is strongly what the data suggests. You know, it is not a controlled study. It is just a striking correlation. But it's not a completely novel concept. The hangry phenomenon, I'm sure. I don't know. Everybody's different. I certainly experience it. But we think that when you are getting strong signals from the body, for example, I think the amygdala is going to be able to detect a lot of different homeostatic inputs, even though we don't have evidence for that yet. But for specifically energy balance, when you're hungry, your amygdala can detect it, perhaps through ghrelin receptors or other mechanisms. And then what we see is that in that food, after one day of food deprivation for mice, you can see this shift in the balance between the positive valence encoding projection neurons and the negative valence encoding projection neurons. At baseline, fear trumps all. The negative projection neurons can silence the reward projection ones, which makes sense if I need to run away from this predator. I can't worry about eating this food right now, but if I'm in a near starvation like state, which for mice, they have very high metabolism. So one day without food is a really big deal. They only last a few days. So at this point they are kicking into survival mode where actually getting food becomes the greater need. And you'll see animals hunting in ways they normally wouldn't hunt when they're really desperate. And so this mode of food deprivation shifts things so that the reward pathway actually has stronger power to influence and silence the fear pathway than before. Wow.

The brain is so smart.

It really is.

It can take what we normally think of as a priority list. Fear and staying safe is more important than food reward. And then if food and acquiring food is critical to survival, it can invert all that, is what you're saying.

Exactly.

Amazing.

And it happens, you know, in a day. It seems reversible. So that's something that we're looking at right now and thinking about how specific is this to food? Is this true for lots of different things? What about exercise, other stressors that are potentially more positive? The amygdala is able to detect a lot of different signals from the environment and we're not sure how all of that gets in there. So I think one of the detection of the environment has been really well worked out in terms of our basic sensory modalities. But think about the things that really affect your emotions day to day. At least for me as a human in this society, the things that affect my emotions most day to day are almost entirely social interactions, very subtle ones, ones that don't seem to threaten my life or safety. You know, very small, subtle social interactions are what, you know, have the greatest bearing, I think, on my emotional evaluation and my emotional bandwidth. And what is that? How do we detect that? How do we assemble this information? Apply all the nuance, you know, put on the onion layers of social programming to come out with whatever, you know, I interpret this gesture to mean it's pretty incredible. And so that's kind of where my research program has been sliding.

Such an interesting area. Let's drill into it a bit and to put it in context, maybe we talk about social media. So on social media, whether or not it's Instagram or X, those seem to be the two major platforms. I'm not on TikTok. People say stuff. Sometimes they say positive things, sometimes they say negative things, sometimes they say things that are sort of neutral. So it seems to me that nowadays, if one is on these social media Platforms that we are, we've sort of crowdsourced this phenomenon of social interaction in a way that we hadn't before. Because I grew up prior to the advent of social media and I could bring my physical body into certain environments and not others. Even at high school, I could hang out. We had an area called the bat cave where, you know, skateboarders and some other, at that time, misfits hung out with the quad where the cool kids hung out, etc. You could, you could pick your niche. Okay, social media is not like that. You can pick followers, they can pick you, etc. But I think since most people have social media nowadays, it seems or on there in some ways that we've placed ourselves in the center of an arena which we have a ton of incoming input. We all, most of us have amygdalas, two of them, amygdala, as you pointed out, one on each side of the brain. And presumably we're on these platforms to receive positive feedback and avoid negative feedback. However, there does seem to be a cohort of people who seem to like the friction of combat or kind of, let's just call it high friction interactions or moderate friction interactions. They like to argue, they like to parse ideas. It's not all bad necessarily. So have you ever looked at social media in your own mind? Looked at social media through the lens of amygdala filtering or through the lens of neural circuit filtering and I wondered what's going on there that someone without your in depth knowledge of these brain circuitries would not think to look at that landscape. Or maybe we could just do that now as a kind of playful experiment.

I like that. So a lot of people ask me about social media from the context of is this social contact meaningful? Is this positive, does this count? Does this help you not feel lonely? And of course I don't know the answer. We haven't done that particular study yet and I don't know of that specific study having been performed. But my prediction is that it's not going to do much because I believe that a key component of what I would consider social contact heavily depends on having some interbrain synchrony, some interaction that is synchronous. And I think with social media sometimes there can be an engaging dialogue that plays out in near real time. But generally speaking, it's asynchronous. You're looking at things that are happened that you're not a part of. You're excluded from all these things.

It happened in Australia yesterday and I'm on there Saying, cool, love it. And then the person's already asleep.

Yes, exactly.

So that's what you mean by asynchronous.

Asynchronous, like that we're not experiencing things at the same time. It's not a shared experience in terms of having that bond necessarily. And so I've never actually been asked about how the amygdala processes social media. I guess I think what happens is the amygdala is just responding to stimuli. It's sending a bottom up signals. It's a caricature of bottom up and top down processing. Let's give an example that I'm walking down the street and all of a sudden I hear a really ferocious dog barking at me. Rah, rah, rah. Going crazy. And then I get super scared. And then I realize, okay, there's a fence. So the amygdala detect, you know, heard the dog barking. Hey, there's a dog barking. And you know, I'm freaking out. Then my prefrontal cortex realizes there's the fence and it looks very sturdy. This fence looks stable. And then I'm relaxing and I'm resuming my walking normally. You know, I think that's sort of the dance that our brain is doing when we have top down and bottom up information that we're trying to stay focused. So for me, I think when I'm on social media, there's so many stimuli that are evoking responses and to be completely transparent, and I know this is not something that everybody else does or can't do or is necessarily what's best for them, but I work very hard to control input from the top down in terms of I really, really limit the amount. I basically don't check email or go on social media. I would say I'm on social media or email less than one hour per week, basically.

Per week.

Per week.

All I have to say to that is congratulations. We'll talk about social media again in a second. But as a fellow professor, email once a week. I've heard of people scheduling their times for email responses, but once a week, that is awesome. No wonder you're so productive.

I have people who help me get through it and then I filter out what's important. But otherwise I just, whenever I do my own email, I say yes to all these things. Then I make all these plans and then I have too many trips and I'm responding fragmented, fragmented. And it's just over committing. And I think I know my limits. Sometimes it's difficult for me to be in my amygdala mode, responding to stimuli and yet letting my prefrontal cortex do its thing. So I've set some very heavy prefrontal, cortically selected limits of the input I put in so that my brain can function and be clear. I can't be creative, I can't have epiphanies if there's all this clutter of like writing this person back and blah blah, blah, blah, blah, tweet, tweet. It's just, you know, trash out, wipe squeegee, squeegee the brain down so that we can actually grow something beautiful and new.

Well, and I want to re emphasize what I said in my introduction, which is that I mean you are oh so productive. And when I say productive, I don't just mean productive like plug and chug. The work you've done is incredibly creative. You transformed our understanding of what this famous structure, the amygdala, actually does. I mean, you've made so many important discoveries as a consequence of presumably other things, but including wiping away all this incoming and clutter, as you said, controlling the top down inputs. I have to ask, just from a practical standpoint, during that one hour a week, are you reading every email that came in or are you just being very selective about which emails? So you're not opening most emails?

No, I don't open most emails. No, I just, I search for the ones that my assistant identifies as the one I need to open. There's like a list of things that I'd be interested in and then we'll go through the list and then, you know, sometimes it requires me to go and find the email and respond to it myself because that is, and then I would do that for, you know, 10, 10 minutes a day or something.

Do you recommend out of there?

As soon as I can.

Love it. Do you pass on this advice to the people that you train?

I think it depends on what resources and what's your, what's the, what's your job right now? Right. So I think as a trainee I definitely did my, as an assistant professor I did my own emails. But at a certain point I was just never getting to the bottom and then it would just stress me out, make me feel overwhelmed. And what is my job? My job is to number one, be a stable core of a sustainable research program. And that just requires me having a lot of mental health and well being and clear mindedness and I need to be able to come up with creative ideas. I need to be able sprint when there's a deadline and I just can't exhaust my system with unnecessary. I would call them Quadrant four in the time management quadrant. If you're familiar with this, you know.

Oh yeah, what is it? Important? Urgent? Yes, important things are urgent, but not important. Some things are urgent.

Some things are neither important nor urgent. That's. Most emails are like if you read time management literature and you have the luxury to have someone else help you or something that's like so well trained to be really good at chaptering things that are important. And you know, sometimes I miss emails, but emails are not the way my trainees would reach me. They would reach me in a different way. And then emails are for everyone else that I didn't give my number to.

You know, I feel so honored to have it. Have you your contact. I'd like to take a brief moment and thank one of our sponsors, and that's AG1. AG1 is a vitamin, mineral, probiotic drink that also contains adaptogens. I started taking AG1 way back in 2012. The reason I started taking it and the reason I still take it every day is that it ensures that I meet all of my quotas for vitamins and minerals, and it ensures that I get enough prebiotic and probiotic to support gut health. Now, gut health is something that over the last 10 years, we realized is not just important for the health of our gut, but also for our immune system and for the production of neurotransmitters and neuromodulators, things like dopamine and serotonin. In other words, gut health is critical for proper brain functioning. Now, of course, I strive to consume healthy whole foods for the majority of my nutritional intake every single day. But there are a number of things in AG1, including specific micronutrients that are hard to get from whole foods or at least in sufficient quantities. So AG1 allows me to get the vitamins and minerals that I need, probiotics, prebiotics, the adaptogens, and critical micronutrients. So anytime somebody asks me if they were to take just one supplement, what that supplement should be, I tell them AG1. Because AG1 supports so many different systems within the body that are involved in mental health, physical health and performance. To try AG1, go to drinkag1.com Huberman and you'll get a year supply of vitamin D3, K2 and five free travel packs of AG1. Again, that's drinkag1.com Huberman I think this is wonderful advice for people to hear. We have a future guest on this podcast named Cal Newport. He wrote the book Deep Work and he has another book called A World Without Email. He's a computer science professor at Georgetown where he talks extensively about the tremendous career but also relationship and life value of doing essentially what you're describing. Although I do think, Kay, that you represent kind of the extreme of what I've become aware of in terms of people that can limit the amount of time on social media platforms and email. Anyway, I just want to say congratulations. I just want to say that again. And I think even if people don't reduce to one hour per week, I think that making some effort toward reducing the amount of incoming, as you said, controlling the top down inputs to the amygdala but also to the rest of the brain involved in creative processing, et cetera, is so key. And we actually do have agency. It just is. It's tough sometimes to build up that discipline. So you're doing a tremendous service by sharing that somebody as successful as you does this presumably is successful in part because you do this. Could we by extension say that many people, since billions of people are on social media, are likely triggering the activation of their amygdala, clouding out other more potentially productive activation of their neural circuits by sort of just making themselves freely available to the thoughts and words and impulses of others? I mean, to me it seems the answer would be yes. But I'd like to know what you think.

I mean, I think, and there's something to be said, there's definitely been moments where I've, you know, gone deep into social media and spent more time in a certain burst, right. That is isolated. And I think that there's a lot to be learned from social media. So to actually, to bring it back to one point you mentioned earlier, on social media, sometimes people just want accolades and sometimes there's a lot of friction. One of the reasons I stay on social media, even though I'm making this big effort to sort of declutter my consciousness is because of that feedback. Especially when, you know, for someone like you, I imagine this has got to be super true. And even for me, at a certain point in my career, it just felt like people don't want to tell me bad news to my face as much anymore. Everybody's so positive all the time and you know, what are they really thinking? And social media allows you the protection of anonymity to say what you really think without consequence, essentially. And so on the one hand, the consequence free nature of being able to just say things can be very dangerous. But at the same time, for me, I really value Just being able to receive it. I'm a big girl. I can filter out what I want when I get all the inputs. But if I don't receive the inputs, sometimes it's hard to learn from the feedback I'm not getting. So even sometimes, feedback's given in a not very nice way. I can still create a model for someone else that has this perspective that I can take with me, and that can be another perspective I can honor easily in the future because I have this theory of mind for someone. Someone would get upset about that. You know, that's something that could be harmful to people who are, you know, have this theory of mind. So I think it's super valuable from that perspective, and that's why I continue to use it.

Great. Yeah, I really applaud that as well. I. I always read my teaching evals because they're anonymous. And yes, I do wonder, you know, what grade the different people who gave different evals got. I don't know that information. I sometimes wonder, do they attend the class, or are they just angry they didn't do well on the exam? But that really represents the small fraction of feedback that I wonder about. Most of it that's valuable to me is the, hey, liked the course, but these parts really sucked. Professor Huberman, or this part was completely unclear or completely hated the way you blank, blank, and blanked because that feedback is something I can really work with to improve. So I think course evals are similar to what you're describing. I think there's value there. If I were to just look at the positive feedback and then ignore the negative feedback and write those people off, then I don't think I could improve as a teacher. Actually. I always encourage comments and feedback and suggestions in the YouTube comments for this podcast for that reason. And I do read the comments I go through and I read, and a few of them sting. But, you know, the positive feedback is great, too. Sometimes it's more of this, please or less of that, please. I think there's information in that.

Yeah.

So I think it sounds like you've been doing all of these things naturally.

So actually, since I've had my research group, my lab, we do an anonymous lab survey every. It's supposed to be about every 18 months, and then it's a whole long process of going through it, and it's just evolved. I think it's the fourth or fifth time we've done it, and so it's now, I think it's like 70 questions. It's so many questions. Maybe we should Trim it down. But it ends up being hundreds of pages of text. You know, short answer, sometimes long answer. Feedback from anonymously from people in my lab. My lab is pretty big. So it's, you know, I'm not even trying to really guess who is saying it. It's just feedback. And it takes me months to go through with it and get all the feedback. And it is so useful. I mean, in a class, the amount of content that you have, it's restricted to this very specific time and space. Whereas when you're mentoring someone over the course of years, there's a lot of different. There's a lot of different points of contact and interaction. And, you know, you're in the lab all 40 hours a week or whatever, and, you know, going trips, meeting here. There's just a lot of different. Different ways to improve in ways that we've never. You know, I haven't had any training in how to be a really great mentor. And so I'm getting that training now. I'm making my own course, and my mentees are my teachers. And I really am grateful for the tutelage that they provide for free in this anonymous lab survey. Sometimes it makes me cry, but sometimes it makes me feel really good about something that I'm doing that's working. And in any case, it makes me feel that I have ground truth. I guess I still don't know, but when people say things that sting, it makes me feel like they're saying what they really think and they're not holding back. It doesn't, you know, and bad news feels like reality. And so that is very. Something about that is rewarding just to feel like I have reality rather than I'm getting something else, you know, that the model doesn't quite fit. It's very unsatisfying when the model doesn't quite fit.

So I love the word ground truth. There's something so beautiful to that, and I resonate with what you're saying. Let's go back to social interaction, something that your lab is doing lots of work on nowadays. And maybe we could shift to the sorts of social interaction that most of us are familiar with. The sitting across the table, having a coffee with somebody, that taking a walk with somebody, maybe a phone call, maybe a tough conversation, maybe a playful, unscripted conversation, maybe a meal at a holiday dinner. There's a huge range there. What do we know about the value of social interaction at the level of core biological needs, at the level of neural circuits, and maybe even hormones? Most people have heard of oxytocin they think the love hormone. But there's so much more there for people to understand and know about. How important is this thing that we call social interaction? And how bad do things get when we're not getting the right kinds of social interaction?

You know, I think this is a great question, and I'm glad that it's become something that has been recognized at a more global and national scale. Just the importance of having social support in our lives for our well being. But social isolation, or even just perceived loneliness, has immense health consequences for all social species. So shortened lifespan, increased mood disorders, increased actually morbidity and mortality for diseases like cancer or heart disease. That might not be what we would normally think. And so I think understanding how each of those processes is happening, those mechanisms are far from being worked out. But the correlational evidence is undeniable. We're now taking this into the lab, really for the first time. And so something so simple as social isolation, how come we don't know way more about it? And I'm someone who stumbled into the field of social isolation by accident prior to the pandemic. And so I'll just say the whole story on why there's such a gaping hole in our knowledge as a near neuroscience community about social isolation really comes from Harry Harlow's work. This original work of maternal separation that was undeniably cruel. It caused irreparable damage to these baby monkeys and they never recovered.

And sorry to interrupt. I apologize. I'm striving to not interrupt in my life. But so that people are on board, could you just briefly describe the Harlow experiments?

Yes. So they're very famous experiments where they separated baby monkeys from their moms and then had either a wire sort of thing holding a bottle. So, okay, what do you miss most about the mom? Is it the food or is it the comfort? And then they had. So they had a wire thing with a milk bottle versus, you know, blankets and cuddly soft things. And the baby monkeys would go to the cuddly soft thing. But, you know, a blanket is not a replacement for a mother. Nobody's saying that it is. And through these experiments, there was extended maternal separation and it was deemed cruel. There was permanent irreparable damage. When you rehoused these monkeys, they never re socialized normally. They had lots of different mental and physical health problems. And I think in humans we know that solitary confinement is considered torture. Social isolation is a difficult thing to study in a lot of conditions. And we stumbled onto it by complete accident through working with a postdoc A former postdoc in my lab, Gillian Matthews, who was a graduate student doing an experiment on it, was just trying to figure out if these dopamine neurons would also respond to cocaine the way VT8, these ventral tegmental area dopamine neurons, were known to respond to cocaine. Wanted to see if these other dopamine neurons respond to cocaine. So sort of a incremental study. So when you do these cocaine studies, you inject the animal with cocaine or saline and then leave the naive animal in the cage. And then you take brain slices, record from the neurons and look at the synaptic strengths. And so the expected outcome sort of was that these dopamine neurons would be similar to other dopamine neurons that showed long lasting potentiation after a single dose of cocaine. But what happened instead was that, yes, there was potentiation in the cocaine animals, there's also potentiation in the saline animals relative to the naive group. And this was a huge puzzle. What was this? And it turned out through many, many different experiments that it's actually because when you inject animals with cocaine, you're separating them from the group because they act all crazy. And this is what the way people did the experiment. So you inject them with saline, you separate them. The naive animals just stay there with their other littermates. With their other littermates.

I see. So the control group, the saline control group, is actually a social isolation condition.

So by accident, this control group, that didn't make sense was how we stumbled onto. So then we tried is it novel cage? It's not the novel cage, it's the social isolation. And so that is how we became a lab that studied social isolation. It was a complete accident. We weren't sure what we were looking at. And then we found these neurons and.