La hipótesis del cerebro triuno es falsa Transcript: Lisa Feldman Barrett Know, the human brain is not larger than you would expect it to be for a primate of our size. If you took a chimpanzee and you grew it to the size of a human, that chimpanzee would have a brain that was the size of a human brain. So there’s nothing special about our brain in terms of its size. There’s nothing special about our brain in terms of the basic blueprint that builds our brain from an embryo is the basic blueprint that builds all mammalian brains and maybe even all Vertebrate brains. It’s just that because of its size, and particularly because of the size of the cerebral cortex, which is a part that people mistakenly attribute to rationality. (Time 0:16:24)
El cerebro opera resolviendo el problema de la inferencia inversa Transcript: Lisa Feldman Barrett Is like this. Your brain is trapped in a dark, silent box. Lex Fridman Yeah, that’s very romantic of you. Lisa Feldman Barrett Which is your skull. And the only information that it receives from your body and from the world is through the senses, through the sense organs, your eyes, your ears. You have sensory data that comes from your body that you’re largely unaware of to your brain, which we call interoceptive, as opposed to exteroceptive, which is the world around you. But your brain is receiving sense data continuously, which are the effect of some set of causes. Your brain doesn’t know the cause of these sense data. It’s only receiving the effects of those causes, which are the data themselves. And so your brain has to solve what philosophers call an inverse inference problem. How do you know when you only receive the effects of something, how do you know what caused those effects? So when there’s a flash of light or a change in air pressure or a tug somewhere in your body, how does your brain know what caused those events so that it knows what to do next to keep you alive And well. And the answer is that your brain has one other source of information available to it, which is your past experience. It can reconstitute in its wiring past experiences, and it can combine those past experiences in novel ways. And so we have lots of names for this in psychology. We call it memory. We call it perceptual inference. We call it simulation. It’s also, we call it concepts or conceptual knowledge. We call it prediction. (Time 0:31:37)
Los cerebros evolucionaron para posibilitar un mejor control motor. Transcript: Lisa Feldman Barrett Motor neuroscientists, people who study the control of motor behavior, believe that senses evolved in the service of motor action. The, what triggered, what was, what was the big evolutionary change? What was the big pressure that made it useful to have eyes and ears and a visual system and an auditory system and a brain basically? And, you know, and the answer that is, you know, commonly entertained right now is that it was predation. That when at some point an animal evolved that deliberately ate another animal and this launched an arms race between predators and prey and it became very useful to have senses, right? So these little amphioxys, these little amphioxys, you know, don’t really have – they don’t have – they’re not aware of their environment very much, really. And so being able to look up ahead and, you know, ask yourself, you know, should I eat that or will it eat me is a very useful thing. So the idea is that sense data is not there for consciousness. It didn’t evolve for the purposes of consciousness. It didn’t evolve for the purposes of experiencing anything. It evolved to be in the service of motor control. (Time 0:38:19)
Nuestras experiencias de cómo funciona el cerebro inducen al error Transcript: Lisa Feldman Barrett Thing we know about the brain for sure is that the brain creates experiences for us. My brain creates experiences for me. Your brain creates experiences for you in a way that lures you to believe that those experiences actually reveals the way that it works, but it doesn’t. (Time 0:42:30)
Libre albedrío como la posibilidad de cambiar tus modelos internos a partir de seleccionar experiencias Transcript: Lisa Feldman Barrett Will. Or the kind of free will that I think is worth having a conversation about involves cultivating experiences for yourself that change your internal model. When you were born and you were raised in a particular context, your brain wired itself to your surroundings, to your physical surroundings, and also to your social surroundings. So you were handed an internal model, basically. But when you grow up, the more control you have over where you are and what you do, you can cultivate new experiences for yourself. And those new experiences can change your internal model. And you can actually practice those experiences in a way that makes them automatic, meaning it makes it easier for the brain, your brain, to make them again. And I think that that is something like what you would call free will. You aren’t responsible for the model that you were handed, that someone, you know, your caregivers cultivated a model in your brain. You’re not responsible for that model, you are responsible for the one you have now. You can choose, you choose what you expose yourself to. You choose how you spend your time. Not everybody has choice over everything, but everybody has a little bit of choice. And so I think that is something that I think is arguably called free will. Yeah, (Time 0:45:11)
Estocasticidad y ruido como un posible mecanismo para la implementación del libre albedrío Transcript: Lex Fridman Computer. Lisa Feldman Barrett Well, there’s lots of magic, would say, so far, because we don’t really understand how all of this is exactly played out. I mean, scientists are working hard and disagree about some of the details under the hood of what I just described, but I think there’s quite a bit of magic, actually. And also there’s also stochastic firing of neurons. They’re not purely digital in the sense that there’s also analog communication between neurons, not just digital. So it’s not just with firing of axons. And some of that, there are other ways to communicate. And also, there’s noise in the system. And the noise is there for a really good reason. And that is, the more variability there is, the more potential there is for your brain to be able to be information-bearing. So basically, you know, there are some animals that have clusters of cells. The only job is to inject noise, you know, into their neural patterns. Lex Fridman So maybe noise is the source of free will. Lisa Feldman Barrett So you can think about stochasticity or noise as a source of free will, (Time 0:47:56)
El libre albedrío como cultivar tu pasado para controlar tu futuro. Transcript: Lisa Feldman Barrett About stochasticity or noise as a source of free will, or you can think of conceptual combination as a source of free will. You can certainly think about cultivating, you know, you can’t reach back into your past and change your past. You know, people try by psychotherapy and so on. But what you can do is change your present, which becomes your past. Lex Fridman Well, let me think about that sentence. Lisa Feldman Barrett So one way to think about it is that you’re continuously, this is a colleague of mine, a friend of mine said, so what you’re saying is that people are continually cultivating their past. And I was like, that’s very poetic. Yes, you are continually cultivating your past as a means of controlling your future. (Time 0:49:20)
El cerebro de una guagua no es el cerebro de un adulto en miniatura. Transcript: Lisa Feldman Barrett I mean, here’s what I would say. What I would say is that the reason why we can be pretty sure that there’s a there there is that the structure of the information in the world, what we call statistical regularities in Sights and sounds and so on, and the structure of the information that comes from your body, it’s not random stuff. There’s a structure to it. There’s a spatial structure and a temporal structure. And that spatial and temporal structure wires your brain. So an infant brain is not a miniature adult brain. It’s a brain that is waiting for wiring instructions from the world. And it must receive those wiring instructions to develop in a typical way. So for example, when a newborn is born, when a baby is born, the baby can’t see very well because the visual system in that baby’s brain is not complete. The retina of your eye, which actually is part of your brain, has to be stimulated with photons of light. If it’s not, the baby won’t develop normally to be able to see in a neurotypical way. Same thing is true for hearing. The same thing is true really for all your senses. So the point is that the physical world, the sense data from the physical world, wires your brain so that you have an internal model of that world so that your brain can predict well to Keep you alive and well and allow you to thrive. Lex Fridman That’s fascinating that the brain is waiting for a very specific kind of set of instructions from the world. Like not the specific, but a very specific kind of instructions. Lisa Feldman Barrett So scientists call it expectable input. The brain needs some input in order to develop normally. (Time 0:51:28)
Tenemos una naturaleza que requiere de la crianza. Transcript: Lisa Feldman Barrett As I say in the book, we have the kind of nature that requires nurture. We can’t develop normally without sensory input from the world and from the body. And what’s really interesting about humans and some other animals too, but really seriously in humans, is the input that we need is not just physical, it’s also social. In order for a human infant to develop normally, that infant needs eye contact, touch, it needs certain types of smells, it needs to be cuddled, So without social input, that infant’s Brain will not wire itself in a neurotypical way. And again, I would say there are lots of cultural patterns of caring for an infant. It’s not like the infant has to be cared for in one way. Whatever the social environment is for an infant, that it will be reflected in that infant’s internal model. So we have lots of different cultures, lots of different ways of rearing children. And that’s an advantage for our species, although we don’t always experience it that way. That is an advantage for our species. But if you just feed and water a baby without all the extra social doodads, what you get is a profoundly impaired human. (Time 0:53:31)
The Relationship Between Physiology and Action: A Neuroscience Perspective Transcript: Lisa Feldman Barrett I’m about to say is actually based on scientific evidence. When your brain begins to form a prediction, the first thing it’s doing is it’s making a prediction of how to change the internal systems of your body, your heart, your cardiovascular System, the control of your heart, control of your lungs, right? A (Time 1:17:27)
The role of brain predictions in empathy Transcript: Lisa Feldman Barrett Absolutely. So, so here’s what I would say. Um, the, you know, there are people who, scientists who will talk to you about cognitive empathy and emotional empathy. And I prefer to think of it, I think the evidence is more consistent with what I’m about to say, which is that your brain is always making predictions using your own past experience and What you’ve learned from, you know, books and movies and other people telling you about their experiences and so on. And if your brain cannot make a concept to make sense of those, anticipate what those sense data are and make sense of them, you will be experientially blind. So, you know, when I’m giving lectures to people, I’ll show them like a blobby black and white image and they’re experientially blind to the image. They can’t see anything in it. And then I show them a photograph and then I show them the image again, the blobby image, and then they see actually an object in it. But the image is the same. They’re actually adding, their predictions now are adding, right? Or anybody who’s (Time 1:43:31)
Los cerebros evolucionaron para controlar el cuerpo, no para sentir o pensar. Transcript: Lisa Feldman Barrett Know, one thing we haven’t talked about is, you know, brains evolved, didn’t evolve for you to see, they didn’t evolve for you to hear, they didn’t evolve for you to feel, they evolved To control your body. That’s why you have a brain. You have a brain so that it can control your body. And the metaphor, the scientific term for predictively controlling your body is allostasis. Your brain is attempting to anticipate the needs of your body and meet those needs before they arise so that you can act as you need to act. And the metaphor that I use is a body budget. You know, your brain is running a budget for your body. It’s not budgeting money. It’s budgeting glucose and salt and water. And instead of having, you know, one or two bank accounts, it has gazillions. There are all these systems in your body that have to be kept in balance. And it’s monitoring very closely. It’s making predictions about, like, when is it good to spend and when is it good to save and what would be a good investment? And am I going to get a return on my investment? Whenever people talk about reward or reward prediction error or anything to do with reward or punishment, they’re talking about the body budget. They’re talking about your brain’s predictions about whether or not there will be a deposit or withdrawal. So when your brain is running a deficit in your body budgets, you have some kind of metabolic imbalance, you experience that as discomfort. You experience that as distress. When your brain, when things are chaotic, you can’t predict what’s going to happen next. So I have this absolutely brilliant scientist working in my lab. His name is Jordan Terrio, and he’s published this really terrific paper on a sense of should. Like, why do we have social rules? Why do we, you know, adhere to social norms? It’s because if I make myself predictable to you, then you are predictable to me. And if you’re predictable to me, that’s good because that is less metabolically expensive for me. Novelty or unpredictability at the extreme is expensive. And if it goes on for long enough, what happens is, first of all, you will feel really jittery and antsy, which we describe as anxiety. It isn’t necessarily anxiety. It could be just something is not predictable and you are experiencing arousal because the chemicals that help you learn increase your feeling of arousal, basically. But if it goes on for long enough, you will become depleted and you will start to feel really, really, really distressed. So what we have is a culture full of people right now who are, their body budgets are just decimated and there’s a tremendous amount of uncertainty. When you talk about it as depression and anxiety, it makes you think that it’s not about your metabolism, that it’s not about your body budgeting, that it’s not about getting enough Sleep or about eating well or about making sure that you have social connections. You think that it’s something separate from that. But depression and anxiety are just a way of being in the world. They’re a way of being in the world when things aren’t quite right with your predictions. Lex Fridman It’s such a deep way of thinking. The brain is maintaining homeostasis. (Time 1:56:07)
Los cerebros evolucionaron para controlar el movimiento y regular la alostasis Transcript: Lisa Feldman Barrett You know, brains evolved, didn’t evolve for you to see, they didn’t evolve for you to hear, they didn’t evolve for you to feel, they evolved to control your body. That’s why you have a brain. You have a brain so that it can control your body. And the metaphor, the scientific term for predictively controlling your body is allostasis. Your brain is attempting to anticipate the needs of your body and meet those needs before they arise so that you can act as you need to act. And the metaphor that I use is a body budget. You know, your brain is running a budget for your body. It’s not budgeting money. It’s budgeting glucose and salt and water. And instead of having, you know, one or two bank accounts, it has gazillions. There are all these systems in your body that have to be kept in balance. And it’s monitoring very closely. It’s making predictions about, like, when is it good to spend and when is it good to save and what would be a good investment? And am I going to get a return on my investment? Whenever people talk about reward or reward prediction error or anything to do with reward or punishment, they’re talking about the body budget. They’re talking about your brain’s predictions about whether or not there will be a deposit or withdrawal. (Time 1:56:09)