Lisa Feldman Barrett: How the Brain Creates Emotions | MIT Artificial General Intelligence (AGI)

Today we're going to try something different. We're going to try a conversation. We have Lisa Feldman Barrett with us. She's a University Distinguished professor of Psychology at Northeastern University, director of the Interdisciplinary Effective Science Laboratory, author of the new amazing book How Emotions Are the Secret Life of the Brain. She studies emotion, human emotion, from social, psychological, cognitive science and neuroscience perspectives. And so I think our conversation may help us gain intuition about how we instill emotional life into future artificial intelligence systems. As Josh Tenenbaum gave you a shout out on Tuesday and said that if you want to understand how to create artificial general intelligence systems from an engineering perspective, we should study the human brain. So with that, let's have some fun. So let me start with a curve ball to conjure up an image of emotion. Have you ever cried while watching a movie that you remember and what movie was it?

I've cried during lots of movies. Let me think. The last time I cried. Actually, here's an interesting thing. When I'm speaking about, when I'm giving an academic talk, I sometimes will talk about a study that we did where we had people watch films and we have them watch the most evocative clips of films. There's several clips that are really powerful and a couple of them, every time I talk about them, I'm going to try not to cry. Now every time I talk about them, I'm describing for the audience what subjects are seeing. One of the clips is from a movie called Sophie's Choice. Does anyone know this film? Raise your hand if you know this film. So we show this is a film about a woman who is forced in a concentration camp to choose which of her children will die in the gas chambers. And so I'm already, you know, if I had a heart rate monitor and respiration monitor, you would see him like it's a really powerful scene. Meryl Streep is Sophie and it's very, very evocative. We also show there's a scene from a film with Susan Sarandon who is dying of breast cancer and she has to tell her 12 year old daughter that she's dying. So this is another scene also that I find very compelling.

And you use these scenes to elicit emotion as part of experiments.

We do, yeah. And in fact, I was just giving a presentation to the Supreme Judicial Court of Massachusetts on implicit bias. And to start the they wanted to understand the neuroscience of implicit bias and whether or not they should be crafting jury instructions for juries to be aware of implicit bias. And to open the discussion, I showed them A clip from a film that was filmed almost 20 years ago actually called A Time to Kill. A scene where Matthew McConaughey is this kind of. It's his closing statements in a case where he is defending an African American man who murdered two European American men who raped his 12 year old daughter. And so the scene is he's this completely pathetic lawyer until the end when he masters this fantastic defense basically of this man on trial for basically avenging his daughter's death. And that one, I hadn't seen that for 20 years, that film, and it brought me to tears, actually. It's just a really powerful, powerful scene and it just really punches you in the stomach. You just can't help but just experience the weight of racism in that room and the brilliance of the closing argument to sort of puncture through it, basically.

Right, okay. So experience. So one of the things you talk a lot in your work and in your book is the difference in the experience of emotion and the expression of emotion. So what's our biggest misconception about emotion? For folks that haven't considered, have only considered emotions at a surface level, I.

Would say one common misconception is that you can look at someone's face and read their emotion the way you read words on a page. That everyone around the world, when they're feeling angry, they scowl. When they're feeling happy, they smile when they're feeling sad, that they frown. The way that I'm saying it sounds preposterous, and it is preposterous. But unfortunately, that is actually what people, a lot of people believe. And tech companies around the world spend tremendous amounts of money and the investment of some of the most creative people on this planet trying to build emotion detection systems, when really what they're building are excellent systems for reading facial movements which have no intrinsic emotional meaning. I mean, sometimes facial movements communicate emotion, but many times they don't. So people scowl for many reasons. They scowl when they're concentrating, they scowl sometimes when. When they're sad. They even can scowl when they're happy. People smile when they're angry, they smile when they're sad. They don't just smile when they're happy. They sometimes smile to indicate, to send a social message that has nothing to do with emotion. And so the idea that there's one universal facial expression, for example, for each emotion is just. There's no strong scientific evidence for that claim.

So how is emotion created then? Because we nevertheless feel like we're observing emotion when we're communicating with others. So how does emotion the creation of emotion change in the presence of others. Does the audience change the display of emotion? Is that essentially the message?

Well, emotions are not displayed, I would say. Right. So basically you and I are having a conversation right now. And part of what, you know, my brain is doing is it's guessing, making educated guesses about what your facial movements mean. So right now you have a slight smile on your face. Not exactly a smirk, but. And so, you know.

I'm Russian by the way, so we're not allowed to show any emotion. I'm trying my best.

You know, I have a friend of mine who is Russian who told me when she moved to this country, actually I've had several friends tell me this, that their cheeks hurt for a year for how much smiling they had to do. I have also a friend from the Netherlands who moved here who told me the same thing. Her face ached for how much smiling she did. And in Bulgaria they have apparently like a name for the pervasive American smile. Kind of like not flattering name for how much Americans smile. But basically when you look at someone's face, you're making a guess about how they feel. And although you yourself are focused on their face, to you it feels as if that's where all the information is. Your brain is actually taking in the entire sensory array. So it's taking in also the sound of the person's voice and the person's body posture and the dynamic temporal changes in all of those signals to make sense of things. It's not. You're not really. The face is not a lighthouse, it's not a beacon that just displays somebody's internal state in an obligatory way.

Nevertheless, there's some signal there, of course. And so what are, what would you say, as far as I understand there's no good answer yet from science is what are the basic building blocks of emotion?

Well, I wouldn't say that there's no good answer from science. I would say scientists disagree. I think it's very clear what the building blocks are. But in one way or another, if you look back all the way to ancient Greece, you can see that there are two kinds of views of emotion that have been battling it out for millennia. One is the idea that you have, I will give you the modern versions of these views, but they really do have a very long history. One is the idea that you are born with circuits in your brain that are kind of pre wired for emotion. So that everybody around the world is born with an anger circuit, a fear circuit, a sadness circuit, a happiness circuit. Some Other circuits too. You have them, we all have them. All neurotypical brains have them. And actually other animals have them too. And the idea is that when one of these circuits is triggered, you have an emotional response which is obligatory. So you have a very stereotypic change in your body. Your breathing changes in a stereotypic way, your heart rate changes, the chemicals in your body change in a particular way. You make a particular facial expression and you, you have a propensity to make a particular action. Like you attack in anger and you run in fear, or you freeze in fear. And then there's another view which says, well, there are some basic kind of ingredients or building blocks that the human mind or the human brain. Now people talk about the brain. Now, there are some basic ingredients that your brain uses, and it uses them to make every kind of mental event that you experience, every action that you take. The recipes are what are unique, the ingredients are common. Just like you can take flour and water and salt, and you can make a whole bunch of different recipes with them, some of which aren't even food like glue. In a similar way, the idea is that your brain has some kind of all purpose capacities. And it puts these ingredients together and it makes a motion as you need them on the spot. And you don't have one anger, you have a whole repertoire of anger. You don't have one sadness, you have a whole repertoire of sadness. And if you grow up in a culture that has no concept for sadness, you don't experience sadness and you don't perceive sadness because your brain becomes wired to make whatever mental events that exist in your particular culture.

So for artificial intelligence systems, the idea of emotional intelligence is really difficult. And it seems like it's an important thing to try to instill. So for human beings, where do you see the importance on the priority list of what makes us human? Where does emotion sit?

I actually think that's the wrong question to ask because. No, I mean, I think people constantly ask that question, but I don't think it's the right question to ask because some cultures on our planet don't even have a concept for emotion. And people don't while they experience what I'm going to refer to as in scientific terms we call affect, which is our simple feelings of feeling pleasant or unpleasant, or feeling worked up or calm or comfortable or having discomfort. These are feelings that come directly from the internal state of the physical systems in your body. Not everybody makes emotions out of those feelings. And in fact, we often don't make emotions out of those feelings. So those Feelings. The way to think about it is that your brain comes wired to regulate your body. Actually, I sort of take that back. Your brain comes wired. When you're born, your brain comes wired with the potential to regulate your body. Infants actually don't regulate their own nervous systems very well. They can't put themselves to sleep. They can't calm themselves down. They can't regulate their own temperature. That's what they need caregivers for. And as caregivers regulate the nervous systems of their infants, that wires the infant's brain, right? So little infant brains aren't born like little miniature adult brains. They're born waiting for a set of wiring instructions from the world. And they wire themselves to the physical and social realities that they grow in. And as they learn to do this, they experience these simple feelings that, you know, of feeling pleasant or unpleasant, feeling worked up or feeling calm. These are kind of like barometer readings in a way. They're very simple, and they lack a lot of detail because of how we're wired. And we have to make sense of them. And the way that a culture makes sense of them is not always about emotion. So I would say, you know, in our culture, when we lose something significant like a loved one, we feel sad. In Tahitian, people feel sick. They have an illness. It's not sadness. 100 or 200 years ago, there was an emotion called nostalgia, which killed people, was thought to kill people after, you know, for example, after serving in World War I. We would now call that depression. It's not just a matter of changing the label of something. It's actually the formation of the experience is very different. So if you want to build an intelligent agent, I don't think emotion is what you need to endow it with. You need to endow it with these basic ingredients that it can use to make whatever experiences or guide whatever actions, make whatever states or guide whatever actions are relevant to the situations that it's in. That will be different if it's an American or a British or a Western urbanized environment, than say, if you were to go to Tanzania and study, you know, the Hadza who are hunting and gathering since that culture, since the Pleistocene.

So do you have words or human interpretable labels on these basic ingredients that we can understand?

I think so. I think the first thing to understand is that when we think about building an intelligent agent, we think about endowing the agent with cognition or with emotion or with the ability to perceive things in the world, because as humans, these are the things that are really important to Us, especially in our culture, thinking, feeling, seeing. In other cultures, they have different ways of parsing things. But the truth is that your brain did not evolve so that you could think and feel and see. It evolved. Brains evolved to control bodies. Brains evolved so that they could control the various systems of the body as creatures move around in order to gain resources like food and water. And a brain has to figure out how much resources to expend on getting additional resources. Now, that may sound really trivial, but it turns out it's actually really hard. And scientists actually haven't really figured out completely how brains do this. I mean, what's really interesting to me is that if you look, for example, at computer vision, try to figure out, you know, how and how to make an agent. See, that's a pretty much solved problem. Not completely. It's a pretty much solved problem. The basics are solved.

The pure perception problem.

Yeah, the pure perception problem. However, if you want to create an agent that just reaches out smoothly, grabs a glass and brings it into the body to drink, that problem is not solved. Something as simple as movement, which we think of as this really basic thing like, oh, it's so trivial, all animals can do it, is actually one of the hardest problems to solve. And brains, basically. I mean, there's a whole story here about evolution, which has nothing to do with having a lizard brain, which is wrapped in a cognitive brain or anything like that. That's a reference to the triune brain, which a lot of people believe. It's a way of thinking about brain evolution. Instead, what seems to be the case is that as bodies got larger and there were more systems, because the niche of the animal, the environment of the animal got bigger and bigger and bigger. Brains also had to get bigger, but they had to get bigger to a point, with some constraints, like they have to be, you have to keep metabolic cost down. It's really important. If you don't, creatures get sick and die. We can talk about what that means in terms of depression or metabolic illnesses or what have you. But. So what are the basic ingredients? Well, one of the basic ingredients is that your brain is controlling your body all the time, whether you feel it or not, whether you're thinking about it or not, whether you're asleep or awake, certain parts of your brain are always very active all the time, even when you're sleeping, or else you'd be dead. And those parts of the brain that are controlling your heart and your lungs and your immune system and all of those regions that are controlling the systems of your body are also Helping your brain to represent the sensory consequences of those changes in your body, which you don't feel directly. You don't feel your heart beating most of the time. You don't feel your lungs expanding most of the time. And there's a really good reason why we are all wired not to feel those things. And that is you'd never pay attention to anything outside in the world ever again if you could feel every little movement that was going on inside your body. So your brain represents those as a summary, these kind of simple summary feelings. You feel good, you feel bad, you feel great, you feel like shit, you feel really jittery, you feel really calm. And these feelings are not emotions. They sometimes your brain can make them into emotions, but. But they're with you every waking moment of your life. They are properties of consciousness in the way that lightness and darkness is a property of vision. And sometimes we make them into emotions. When we have a big change in our heart rate or a big change in our breathing rate, or a big change in our temperature, or a big surge of glucose, we might. The brain might make emotion out of those changes, those very strong changes which you will feel as really feeling unpleasant or really feeling pleasant. But your brain might also make hunger. Or your brain might make an instance of a physical sensation like nausea. Or your brain might even make a perception of the world like, that's a nice guy. That guy's an asshole. This is a really delicious drink. That's a beautiful painting. Those are also moments where these simple feelings which we call affect, are very strong. So affect is a basic ingredient. There are others that I could talk about too. It's not the only one. But one of the things I think that sometimes people who are studying to build AI and systems don't realize is that the brain, its fundamental job is to keep your body alive and well. And if you don't have some kind of body to regulate with affective feelings that come from that regulation or something like that, you're kind of going to be out of luck, I think, in rendering something that looks more. Something that seems more human.

Right. So maybe you can elaborate, like in the book Sapiens, that as human beings are really good en masse, with thousands, millions of people together believing something, even if it's not true. So while scientifically, sort of from a neuroscience perspective, it's maybe very true that emotions aren't real.

I didn't say they aren't real, but I said they're not there isn't. So it's interesting. Well, you finish and then.

So what I'm trying to say is also from an AI perspective, is they become these trivial ideas of mapping a smile to being happy. And these kind of trivial ideas become real to us through Hollywood, through cultural spreading of information. And we start to believe this, and therefore it becomes real in as much as anything is real about our perception together. So it's really important scientifically, the ideas that you're presenting. But does that mean there's. Just because our brain doesn't feel those explicit emotions, does that mean they're not real?

I didn't say we don't feel explicit emotions. So I want to be really clear about this because it's an interesting. This, you know, this inference. It's an interesting inference that people often make. And so. But it's a mistake. And it's a mistake that betrays a certain kind of thinking that we do in this culture. And it's a mistake of the following sort. So when I say there is no facial expression that is diagnostic of a single emotion, that doesn't mean that people don't express emotion. They certainly do express emotion. They just don't. You know, when. When they're in a state of anger or in a state of sadness or in a state of awe, their faces don't do one thing. When I say, well, your body can do many things when you're angry or when you're sad or. But let's take anger. Your heart rate can go up, it can go down, it can stay the same. Your breathing rate can go up, it can go down, it can stay the same. The same pattern that you see in anger, you sometimes see in sadness and you sometimes see in fear. You sometimes even see it in enthusiasm and in awe. So does that mean that emotions aren't real? No, emotions are real, but sometimes things are real because the physical meaning of the signal is endowed in the signal. Okay, so when your retina communicates to your brain that you have that you are faced with a wavelength of that is 600 nanometers. The signal is endowed in your brain that's like in the signal. It's not like interpret. You don't interpret that. It's 600 nanometers. It is 600 nanometers. The information's in the signal. But when you see red, that information is not in the signal. Your brain has added information that isn't in the signal itself. In a sense, your brain has imposed meaning on a signal that the signal doesn't have on its own. Let me back up and give a different example to make it a little easier, and then we'll re approach this. There are some things that we impose. In fact, this is true almost of all civilization, right? That there are some things that are real by virtue of the fact that we agree that they exist. Little pieces of paper serve as money, or now Bitcoin, or little pieces of plastic or gold or diamonds, or in the past, barley, salt, shells, rocks, serve as currency, have value only because a group of people agree that they have value. So we impose meaning on objects. And once we all agree that that object actually has value, we can trade it for material goods. The minute that some of us disagree that we withdraw our consent, right? The things lose their value. That's what happened in the mortgage crisis. That's what happened in the tulip crisis in the Netherlands in the 17th century or 16th century, or when it was money. Currency exists because we impose meaning on objects in the world, physical objects in the world that themselves don't have that meaning on their own. And they are very real. Money is very real to people. I can stick somebody's head in a brain scanner and show you that they experience value in a very real way, but that reality is constructed by the fact that they have learned the value in a particular culture. Well, that's also what we do with emotion. We impose meaning on certain physical signals that they don't have on their own. But we have collective intentionality. We all agree that scowling is sometimes anger, and so it becomes anger in a very real way, just like little pieces of paper become money.

So it sounds like you kind of think about the expression of emotion as a kind of language, as an extension of a language that we learn. In the same way that we collectively agree on a language, on a lexicon, and how we use that language.

Sure, you could think of it that way. I mean, everything in our culture is. Almost everything in our culture is a function of social reality. In this way, we are citizens of a country because we all agree that the country exists, more or less. And wow, you guys barely even laughed at that. Okay, what's a revolution? A revolution is when some people in the country withdraw their consent. They no longer agree. Right? A president has powers in a country because we all agree that a president has powers. President only has powers by virtue of the fact that we all agree that he or she has powers. If we stop agreeing, the president doesn't have those powers anymore. It's very real. People's lives depend. Outcomes of real people depend on these social realities that we build and nurture and we wire These social realities into the brains of our children as we socialize them. And when people move from one culture to another, they have to learn the new social reality that they are faced with. And if they don't, they get very sick physically. Because our ability to agree on what something means actually is important for regulating our nervous systems.

So can you speak to that a little bit? For machine learning methods, for systems that learn to behave based on a certain reward, it's important to kind of have some ground truth and learn. So how do it sounds like the expression of emotion is learned. Can you talk about how we learn to fit into our culture by expressing emotion with our face body? Given the context, given the rich, what's that process look like? When does it happen? How much is happening?

Sure. Well, you know, I mean, I wrote a 400 page book, so I'll try to do it in like a couple sentences. Yeah. So how does an infant learn anything? So an infant's born and it can't really do anything for itself. It can't regulate its own nervous system. It can't keep its body systems balanced. This is a term, scientific term for this is allostasis. Allostasis is your brain's ability to predict what your body's going to need before it needs it and tries to meet those needs before they arise. An example would be if you're going to stand up, if your brain's going to stand you up, it has to raise your blood pressure before it stands you up. If it doesn't, you'll fall. That's costly. From metabolic standpoint, it's costly. You'll hurt yourself. An infant's brain can't do this very well. An infant doesn't know when to go to sleep and when to wake up. An infant can't feed itself, can't regulate its own temperature. Someone else has to do it. And when someone does it, the infant is learning. The infant is learning. It's taking insights and sounds and smells and the physical sensations from the body which are comfortable and pleasant. When the infant allostasis is maintained right from the get go, an infant is learning. Statistical learning, capturing events including their consequence for the infant's body. Some people think babies are born attached already to their caregivers, but they're not. Actually, infants don't even know what a caregiver is. It's just that the caregiver is there constantly meeting that infant's needs. That's how infants start to learn. Now, if there are statistical regularities, like for example, an infant is not born with the ability to recognize a face as a face. But it learns that in like the first couple of days of life. Why? Because human faces have some statistical regularities to them, right? Two eyes, a nose, and a mouth kind of in the same place most of the time. So it learns really quickly. But here's the interesting thing. Around three months of age, infants start to learn what we call abstract categories. They start to learn that some things which don't look the same or sound the same or smell the same actually have the same function. And how do they learn this? They learn it with words. So if you do an experiment with a three month old, three months old, okay. And you say to that baby very, very intentionally, look, sweetie, this is a wug. And you put the wug down and it makes a noise like a beep. And then you say, I'm like, I don't have props. And then you say, I have my wallet. Yeah, okay. And then you say, give me your wallet. Yeah, give me your wallet. And then you say, look, sweetie, this is a wug. And you put the wug down and it makes a beep. If you say, look, sweetie, this is a wug, that infant expects that object to beep. Why is that important? Because in the real experiments, this might be yellow and squishy and tall, and this might be red and pointy and, you know, hard, and this might be, you know, so lots of different perceptual features. But the infant knows, learns that the word is inviting the infant to understand that the function of those very different physical signals are actually the same. Similarly, you can take six objects that are exactly identical in their physical features. How they sound, how they smell, what they feel like, what they look like, and you can name three of them with one word and three of them with the other word, and the infant will understand that these are actually different objects. That happens a little after, you know, not. Not as early as three months. But the point is that we talk all the time, we use words all the time. What do we do with infants? We're constantly pointing things out and labeling them. This is a dog. This is a cat. You're angry. This person's sad. Oh, mommy's really happy today. Oh, you know, mommy loves you. Oh, daddy's really excited about this, and so on and so forth. And infants learn really, really quickly. Words are considered to be kind of invitations to form abstract concepts. That is the basis of almost all of the, you know, mental categories that we, that we. Mental events that we experience. We're basically teaching children to form these Abstract categories. And that's the basis of money, and it's the basis of roles that we have with each other and what we expect from each other. It's the basis of a lot of the sort of functional categories that we use in everyday life. We impose meaning on sensory. On sensory arrays that those sensory arrays in and of themselves don't necessarily have. They only have that meaning because you and I both learn that that package of sensory array means something. So when I make that, you can anticipate what will happen next. Just because we've learned those, they're wired into our brains in our culture. And when we go to a different culture, we have to learn sometimes different packages.

Yeah. Different mappings. So you're saying that there's a few sources of sensory data and a few building blocks inside us. The feelings of some kind that we learn to. Then from an early. We become born with those.

Or part of what your brain is doing is it's trying to make sense of the sensory array around it. So from your brain's perspective, so from your brain's perspective, just think about it from your brain's perspective, your brain's perspective, it spends its entire life trapped in a dark, silent box. And it has to make sense of what's going on around in the world so that it knows what to do to keep itself alive. Right. And, well, but it has to. It has to know what to do based on. It has to know what's happening all around it only from the effects that it receives through the sensory systems of the body. So a flash of light. What's a flash of light? It could be anything, like a siren. A siren could be a fire truck, or it could be somebody's car alarm went off, or it could be a doorbell, or it could be any particular sensory cue. Could have multiple causes. So your brain's trapped basically in your skull, and all it gets are the effects, the sensory effects of stuff that happens in the world. But it has to figure out what those things are so that it knows what to do. So how does it do that? Well, it has something else that it can draw on. It has your past experiences. Your brain basically doesn't store experiences from the past. It can reconstitute them in its wiring, and that's what it uses to guess at what those sensory cues mean those sensory changes mean. So in one situation, a siren means one thing. In another situation, it means another. A flash of light means one thing in one situation and a different thing in another. So your brain is using past experience to make guesses about what these sensory changes mean so that it knows what to do. And it has the same relationship to the sensory changes in your body. What's an ache in your stomach? Well, it could be hunger, it could be anger, it could be disgust, it could be longing, it could be nausea. It's not that there's one ache in your stomach for nausea and another ache in your stomach for hunger. There are many aches in your stomach, many different feelings of achiness for nausea and many different feelings of achiness for hunger. And sometimes they overlap. So your brain has to make the same kinds of guesses about what's going on in your body as it does about what the sensory events mean in the world. And that's really what it's doing. It's guessing and making sense of the sensory array so that it knows what to do next. And when it guesses wrong, it takes in that information that it didn't predict. Well, which in psychology, we have a really fancy name for that. We call it learning. Your brain takes in the information that it didn't predict so that it can predict better in the next time to make sense of things the next time.

So you kind of answered this a little bit. I'd like to elaborate on it. If you were to build a robot that performs, maybe passes the touring test or performs at the low bar level of instead of myself here today, it would be a robot talking to you. It would be convincing as a human. How would you. What kind of. How would you build that system? In a sense, in paralleling the infants. What essential aspect of the infants. Infant experience do you think is important?

It needs. Well, I mean, I'm not a computer scientist. The way that I would say it is it needs to have a body, needs to have something like physical systems or an analogy to physical systems. It has to do something analogous to allostasis.

Sorry to elaborate. So what would be the goal for the system? You kind of mentioned previously that the goal would be for the brain to just stabilize itself.

No, it's not that. The brain is stabilizing itself. So people talk about reward. What is reward?

Machine learning is pretty easy. It's something, it's mathematical. So there's no philosophy to it. You just.

Oh, there's philosophy to everything. Right. Whether you admit it or not is a different story. Right? Yeah.

So you wanted to play a game of chess, playing a game of Go. You wanted to pick up a water bottle.

Okay. But what is reward.

Existence?

Dopamine is actually not reward. Dopamine is Effort, Dopamine is necessary for effort. It's not necessary for reward. I mean, it's commonly, if you read the most up to date literature, that is what you'll see that it's actually people can, animals can find things rewarding can be without, without dopamine, actually. But they, they, they need dopamine to move, they need dopamine to encode, to learn information. So it's really for effort that is required to work towards getting a reward, I would say. And when the, when a brain, an animal brain, a human, you know, any kind of animal brain mispredicts what the reward will be, that's when you see a real surge of dopamine because the animal has to adjust its action. But reward is basically bringing the body back into allostasis. It feels good when that happens and people will, and animals will work tremendously hard to have that happen. So, you know, what is motivation? Motivation is expending resources to get a reward. So basically, if you don't have something like physical systems that have to be kept in balance, water, I mean, for humans or for actually any living creature on this planet, even single cell organisms, actually there's an analogy to what we're talking about here, to brains. But salt water, glucose, all these systems have to be kept in balance and they have to be kept in balance in a very, very efficient way. That's the motivating, so called motivating force. Really. That's what really brains are for. And that is the basis, the consequence of that regulation are the basis of affective feelings, which are for many, many creatures on this planet, a property of consciousness.

Okay, so maybe if it's okay, we'll take some questions from the audience.

Sure.

But first let me ask the last question. So building on the robot question, how would you build the same kind of robot that you would be able to as a human being, fall in love with?

Well, you know, people fall in love with their cars, they fall in love with, they fall in love with their blankets, they fall in love with their toys. You know, it doesn't need much to fall in love with something. The question is, will it love you back?

No. Well, I would elaborate. I think, I think you're answering that love in the way we're defining it loosely in poetry and culture as a social construct. And it's relative. What I mean is sort of the idea of monogamous long term love, that we have deep connection with other human beings, that we have. You're saying you could do the same with a car, like a nice.69 Mustang.

Are you telling me that you. You're telling me that you've never. You don't know anyone who is like so in love with that. Their car that you. Okay, now here's the thing. So here's the thing. We are social animals. Okay? What does that mean? What does it mean to be a social animal? It means that we regulate each other's nervous system. So my brain isn't just regulating my nervous system right now, it's regulating yours. And actually it's regulating other people's in the audience too, and vice versa. And why is that? I mean, other animals do it too. We're just really good at it. But other animals, like there are some insects that are social species, they regulate each other's nervous systems. They do it with chemicals, they do it with smell, primarily, and a little bit with touch, like earwigs. Will I have this great picture of this totally disgusting looking little bug, but it's like cuddling its little baby, little ugly baby bug too. It's adorable picture. But what about mammals like rats? Well, they also use chemicals like smell, but they also use touch. And to some extent, they also use sound, they use hearing. Primates add vision. And as primates, we use all of those senses to regulate each other. And we also use something else. Words. Right, Exactly. And words, the systems in our brains that allow us to speak and allow us to understand words, are directly connected to the parts of the brain stem that control the body. I don't mean like there are a bunch of, I mean, monosynaptically connected. So exactly the same systems in your brain that are important for you to be able to understand language and to speak are also directly, directly affecting the systems of your body. And that is why I can say something to somebody, I can speak to you, and I can have an impact on the nervous systems of people all the way at the back of this auditorium without they, you know, maybe they can see me, maybe they can't. Maybe they can. Hopefully they can't smell me. Maybe they can hear me. Maybe they, you know, but they can. If they hear me speak words, I can affect their nervous systems. That's why a telephone works. That's why a telephone works where you can feel connected to someone just merely by hearing their voice. Because the sound of their voice has an effect on your nervous system. It can make you breathe faster, it can make you breathe slower. And the words also have an effect because when I say a word like, I don't know, when I say a word like car, that's a short form. I have a bunch of mental features in my mind when I say the word car. And I say that word, and that invokes those similar mental features. Maybe not identical, but similar enough, that invokes it in your mind. And your mind is made by your brain, so it invokes. If I just say the word car, There are changes in your motor system that would be exactly the same or very close as if you were actually in a car. Right? So this is something that we do. And the fact where attachment comes from an infant to a caregiver or two lovers or two really close friends, comes from the ability that we have to regulate each other's nervous systems. And that is why when you don't have that kind of attachment, you die sooner. On average, seven years sooner. Loneliness kills. I always tell my daughter. My daughter's 19 years old, and I always tell her, you know, breaking up, when you break up with someone, it feels like it will kill you, but it won't. Loneliness, however, will kill you. It will kill you on average, seven years earlier than it would if you didn't have an attachment. And that's because our nervous systems, as our bodies got really complex through evolution and our brains got bigger, they could only get so big. There are constraints on how big any brain can get that have to do with birthing the infant, but it also has to do with the metabolic cost of a brain. Your brain is really expensive, My brain, really expensive. Three pounds, 20% of your metabolic budget. That's a lot. And so what did evolution do to solve this problem? Well, it couldn't make our brains any bigger, so it just entrained other brains to help manage our nervous systems. So you bear the burden of other people's allostasis, and they bear the burden of yours. Not always at the same time. But that's what it means to give people support. When you're feeling horrible and somebody pats you on the back or says nice words to you or gives you a hug, they are physically having an effect on your body, that they are helping your body to maintain allostasis at a time when your brain probably couldn't manage it on its own. And so the basis of love or attachment is basically that it's the ability to affect each other's nervous systems in a positive way. I always say to people, the best thing for a nervous system, a human nervous system, is another human. And the worst thing for a human nervous system is another human, because we're social animals.

Beautifully put. So maybe a few questions from the audience. Do you mind? There's microphones on both sides. Go ahead. Sure. Hi. Thanks for talking here. You're saying cool stuff.

Thanks.

It's not a question.

Okay, I'll take it. It's all right.

So I was thinking about what you were saying about reward, and I'm wondering, first of all, is you described it as a return to allostasis. Is reward in any way linked to the. Just like the reinforcement of pathways or behavior so that the next time you get that stimulus, you'll respond in the same way. And I'm also wondering about the link between the desire for allostasis and the need for novelty and the need to explore environment.

It's a really great question. So the second question is so much more interesting than the first, actually. So let me say this, that there is a need for novelty. The need differs for different people. I will say novelty. So, first of all, We can think about the need for novelty in a really proximal way. We can think about it in a really distal way, like. But basically, when I say that a brain is organized or engineered for metabolic efficiency, that doesn't mean that the goal is to only ever have your prediction. Your brain's predicting all the time, to always have its predictions completely perfect. So you never learn nothing because you'll be bored out of your mind. Right. And also, humans like to expand their niche. They like to explore. It's a constant balance between what biologists would call exploitation and exploration. Novelty, it's exciting. There's actually an increase in norepinephrine, an increase in arousal. It feels really exciting. But it's also super costly. Novelty requires usually that you learn something new. That means that's actually really metabolically expensive thing to do. And it also means usually that you're moving your body around, which is also metabolically expensive thing to do. So the need for novelty is balanced by its cost. And different nervous systems can bear different amounts of cost. So, for example, if you take two rats that are somewhat genetically, you know, like they've been genetically bred, one is bred. When you stick it in a novel cage, it just sits still. And the other one, when you put it novel cage, it like, roams all over the place. And it's just, you know, it's going crazy kind of exploring everything. Well, the one that sits still, scientists might say, oh, that's a nervous rat, or that rat's afraid. What is that rat doing? The rat is not moving and it's not encoding anything, because encoding something is expensive. It's expensive. This Rat, on the other hand, is roaming all over the place, moving a lot, learning a lot. So it's encoding a lot. Spend, spend, spend, save, save, save, spend, spend, spend, spend. There are differences between people and there are also differences between times in your life where moments where you feel like you have a little bit to spend and other moments where you feel like you really have to conserve. When I talk to the public, I always talk about. I don't use the word allostasis, it's just too boring a word. But I sort of do is sort of explain it like a budget. Like your brain is sort of like the financial office of a company. A company has lots of offices. It has to balance the expenditures and revenues and. And it's got to keep everything in balance. So it might take a little money here, move it over to that office. It's got to keep everything in balance. What it's always trying to do is spend a little bit to make a little bit more. What happens when it spends a little bit and it doesn't get a revenue back? There's no reward. What happens? Well, it goes into the red a little bit. So what do you do when something goes into the red? Well, you might do something risky. You might actually spend a lot to try to really make, not just make back your deficit, but actually make a lot of. That would be novelty. That would be move and spend, move and encode. Or you might reduce your spending. You might say, well, I'm going to save a little bit. Now that would be. I'm not going to move too much, I'm not going to spend too much, I'm not going to encode anything. So I certainly don't mean to suggest to you that novelty is unimportant or that learning is unimportant. And it's a really important question about what. Is there any intrinsic value to novelty over and above the rewards that it would give you in an allostatic sense? But it is really clear to me that the extent of.