Hands, brains and society

Hands, brains and society
Frank Wilson

People wear college rings. People wear all kinds of things [on their hands]. People put tattoos on their hands. People paint their nails. People put really amazingly elaborate decorations on their nails. Decisions about whether somebody is a person that you would want to know or not can be made instantaneously on the basis of what their hands look like. We also have whole cultural traditions of expressive communication based upon hand movements. Thai dancers, for example, learn how to move their hands in a particular way.

Up until now, I’ve sort of talked about the mechanical stuff; proprioception, if you will, object handling, control of frictional forces, but something else that the hand has come to be very important in is communication. You can make the sort of surface statement, well, people who don’t hear and who are not able to speak because they can’t hear use their hands for something called signing. And, we all know about gestural language. I’m sitting her waiving my hands, communicating in a certain way. However, a great deal of social interaction, beginning in early childhood, beginning essentially in neonatal life, with the child touching its mother’s breast while it is suckling is based upon contact with the hands. We communicate all kinds of things about ourselves and each other. A simple example: I have a sore knuckle right now, so I am not wearing a wedding ring, but normally I do. People wear college rings. People wear all kinds of things [on their hands]. People put tattoos on their hands. People paint their nails. People put really amazingly elaborate decorations on their nails. Decisions about whether somebody is a person that you would want to know or not can be made instantaneously on the basis of what their hands look like. We also have whole cultural traditions of expressive communication based upon hand movements. Thai dancers, for example, learn how to move their hands in a particular way. Anyway, it goes on, and on, and on.

One of the things that I think we also need to understand is that very early on children learn that what they do with their hands earns them status. It brings them in contact with others. Kids can play musical instruments; they get good at throwing a ball; they get good at shooting bow and arrow; they get good at x, y and z. Right now, for all the things that I think are negative about it, we also have strong evidence that there are whole cultural worlds that are building up around the use of small communicative devices that are manipulated by touch, keypads of various kinds. The Japanese have a word, which I have forgotten, for the “Thumb Tribe,” based upon the fact that kids who use these small, handheld electronic devices now, now, when they press a doorbell, they press it with their thumb.

We think we get it – but often don’t

We think we get it – but often don’t
Frank Wilson

What people don’t understand is that what’s profoundly important about the brain is that it didn’t just land from outer space. It came into being as a structure that controls human behavior and human thinking because of millions of years of experience specializing in, if you will, basing survival of the species, and defining that species on the basis of what it was able to do with its hands.

When you spend a lot of time thinking about something, and you take the trouble and you gain the pleasure of learning what other people have thought about it and done about it, you can suffer from a sort of immersion blindness, and you think, of course this is obvious. You forget what is was like or what you thought before you learned all the things that you learned. It’s astonishing to you that other people don’t see it as clearly as you do because it is pretty obvious. I had one of those moments when I was describing what I was describing to you, as the talk that I gave in London, when I realized that I was sitting in a room full of people whom I was sort of terrified of because they know so much more than I do. Then, I discovered that the only thing that I know that I think is worth knowing, they didn’t understand at all. I mean they sort of got it in a very general sense.

It’s a little bit like another experience that I had that was very humbling to me. I was working in Germany, studying a fairly complicated neurological problem having to do with musicians and hand control, and I had become acquainted with a physician who was one of these meticulous German scientists who had developed a technique for studying the biomechanics of joint motion in musicians. He came to a conference that I had organized that was held in Denver, in 1984, called The Biology of Music Making. He presented this material, and I listened to it, but I said, “It’s very interesting, but this is all charts and graphs and spreadsheets of numbers with numbers after the decimal point, and unless you really are an accountant, you look at that stuff and you don’t see anything but numbers.” I then edited the paper that he submitted for the proceedings of this conference. I really struggled with that paper because I was trying to see how to get his point across because it was so arcane; it was so difficult; it was so obscure. That was in 1984. In 1989, I went to Germany, when I went to the University of Düsseldorf, and I went back to see this guy whose paper I had edited. For the first time, I actually was in his laboratory and I brought to him patients that I was seeing. Suddenly it hit me that all of this microscopic examination of joint movement had profound implications for the problems of the people that I was seeing. So, for the first time what he had been telling me—and I spent enough time to be able to edit his paper, talk about his paper—I had no idea what he was talking about until I actually brought him a problem that was real to me, that came out of a completely different set of experiences and complaints and problems. And it was like, oh my God; you just didn’t get it!

So, I said I have sympathy for the people who are psychologists sitting in this auditorium listening to me talk because I realized that they don’t know what the flexor digitorum profundus is, and they don’t know what the opponens pollicis is. They don’t know how they are attached and they don’t know why the anatomy of the hand hamate bone is particularly important in relation to a certain kind . . . They just . . . That’s hard stuff! You know people spend years learning this, and if these guys have been off learning about the brain and the limbic system and the supplementary motor area, on and on, all this brain stuff, how could they possibly be expected, even if they have been playing the piano themselves, they have not connected those two bodies of technical knowledge.

So, I appreciate the fact that even though people can say, oh yeah, I get it; the hand and the brain are connected. OK, but that doesn’t have anything to do with how the brain actually works because the brain runs everything. You know, you shoot somebody in the head and the hand doesn’t work anymore; they have a stroke. Yes, I agree with that. However, what they don’t understand is that what’s clearly, profoundly important about the brain is that it didn’t just land from outer space. It came into being as a structure that controls human behavior and human thinking because of millions of years of experience specializing in, if you will, basing survival of the species, and defining that species on the basis of what it was able to do with its hands.

Proprioception

Proprioception
Frank Wilson

Even at a very early age, all children have a repertoire of that have been called exploratory procedures. They will apply the hand to an object and they will detect the temperature, if the tips of the fingers are on the surface of it, they begin to recognize, sort of crudely, something is very cold or something is hot, and gradually that gets to be more refined. We learn to detect the texture of surfaces by moving the hand over them, and there are very particular receptors in the hand that are very good at picking up small differences, picking up ridges, picking up resilience, and so forth. Over a long period of time and with lots of experience, we become very, very good at that.

First of all, proprioception is a big word and it’s a relatively dry concept. It just means a detection of what is next; Proprius is the Latin word for “next.” And, it doesn’t mean next in time; it means next in space. So, it’s a system that is in the body that is meant to, if you will, control the body in movement in space.

My reason for bringing this up was because thinking about proprioception in sensory physiology is really thinking about information that comes to the body through physical contact with the environment and movement through the environment. Proprioception also includes, for example, joint position sense, and this is information that we need in order to walk, to stand, to balance ourselves. You’ve got to have decent proprioception to be on a skateboard or a bicycle or rollerblades or skis, any of these devices. But, I think what’s happening and what you’re referring to, and what I think is really important, is that we really don’t have a sense of the objective, physical world in which we are absent, because we acquire that sense by presence and by contact with the world, and we do it through our feet by walking around and climbing and jumping and running and standing. We do it by lifting, by balancing, by touching. We may have an immediate sense that a glass is going to be slippery because it also happens to be cold. We can actually learn to tell that we have to increase the force that we apply to an object because it is slippery.

Even at a very early age, all children have a repertoire of that have been called exploratory procedures. They will apply the hand to an object and they will detect the temperature, if the tips of the fingers are on the surface of it, they begin to recognize, sort of crudely, something is very cold or something is hot, and gradually that gets to be more refined. We learn to detect the texture of surfaces by moving the hand over them, and there are very particular receptors in the hand that are very good at picking up small differences, picking up ridges, picking up resilience, and so forth. Over a long period of time and with lots of experience, we become very, very good at that.

We can put our hand in our pocket and we can sort out a nickel from a dime. We can sort out one set of keys or a particular key from another key. All of that comes about because we have simply gained experience over and over, again, and we’ve had a chance to cross check. I take this thing out of my pocket and I look at it. Oh, I thought that was a nickel and it’s a dime.” The more you do that, the better you get at that. In fact, those are neurological tests actually asking people to identify objects by touch. And there are very specific neurologic disorders that produce a breakdown. That’s part of the neurologists diagnostic kit, is to be able to sort of tease those apart and say, well if you can do this but you can’t do that, then the problem must be there. That’s kind of the game that we play.

Transcending imaginative limitations

Transcending imaginative limitations
Frank Wilson

The job of childhood is to pick things up and to play with them. Our job is to make noises and to listen for what comes back at us. Our job is to look at what is around us, to be attracted to it and then to play with it, and to acquire experience in the actual world in which we happen to live, in the century that happens to be the active century when we get here.

If you are interested in the experiences of the body and, if you will, the projections that are made about what the body might be doing. I mean imagine, for example, kids putting on a cape and saying, “I am going to be Superman and I am going to fly out the window. The kid has to have actually stepped off of a step and fallen down to understand that that’s a problem and that you have to have a fantasy about it. I mean the thing is; well, what are my limitations? And then, how do I do something so that I don’t have that limitation, anymore? I mean this clearly is what Leonardo was doing. I went on a trip once to Italy, and outside Florence we were taken to a place where the local story is this is where he tried his first flight. And, you have the sense that it had to be a guy who was fascinated with the physical body and who had a lot of experience with it handling materials and just being in love with the body as a machine to have started having ideas about how do we modify the body, or how do we amend the body, how do we implement the body in such a way that we can do more? It’s that—I think that seeing that history about how people came to think about a new way of doing something and it has been going on for a very, very long time.

The thing is that, again, if you get back to the experience I was talking about earlier with the child who is picking up an object. I mean, I’m holding a glass of water now. We take this to be such a natural thing that you don’t even have to look. You know you want a sip of water; you bring the water here; you do that and you return the glass. Well, it takes, probably, five or six years of rehearsal before a child becomes fluent in that kind of movement. And fluent doesn’t mean just moving it back and forth. Fluent means controlling the muscles that control the degree of pressure that is sensed and used in a precise way to do what it is that you might want to do. I might want to pick up this glass and throw it across the table at somebody who has annoyed me, or I might want to throw it over my shoulder. I might want to drop it on my head. There are a lot of things that I might want to do. I might want to spill it on the floor. The interesting thing about a physical act like that is that over a period  time the social implications of manipulating a glass—if a kid in a highchair pushes it off the table and it splashes, and Mommy comes in, that’s interesting!

There is a lot of learning that goes on. It turns out that people have actually discovered that there is a very particular sound profile of a glass bounding as opposed to breaking that allows the determination to be made without looking that the glass either broke or it bounced. So, children are also playing with different materials; plastics, glass. They are learning a whole universe of important and useful information. Why is it that when put cold chocolate in a glass, you can turn it upside down and it doesn’t fall out? Well, what if you . . .? You know, the questions multiply, they simply multiply; they never stop. It is the interesting thing about children, I think, and that they have inside them a set of instructions about how to move around in the world, about what they need to learn. This is a notion that is spelled out in Henry Plotkin’s book, Darwin, Machines and the Nature of Knowledge, about—he uses the fancy Greek word, “heuristics,” which means teaching devices. What we don’t have is a lot of information about the actual world that we’re going to see. The world looks very different now than it did a thousand years ago, or ten thousand or a hundred thousand years ago. It still has trees and plants and it has horses and animals and stuff, but it has a lot of stuff now that wasn’t there before, so the surface texture has changed. Well, if we have the same brain that expected to see horses and, you know, a lot of stuff that isn’t there, then we’d be lost. So, the human brain is programmed not expect all of those things, but to expect a sort of stable physical environment, and that has taught us, even as young children, that our job is to pick things up and to play with them. Our job is to make noises and to listen for what comes back at us. Our job is to look at what is around us, to be attracted to it and then to play with it, and to acquire experience in the actual world in which we happen to live, in the century that happens to be the active century when we get here.

So, evolution has equipped us to use our body in an extraordinary way, to acquire information about, make inferences about, and then develop a sort of prospective or projective intelligence about what to do in order to be successful as we grow up in the world. Proprioception sounds very remote from that, but in fact, it is acquiring this repertoire of physical skills in relation to the objects around us that seems to produce the flowering of an imaginative or image-based competence to deal with the world, whether it is the world as it really is, or it is the world we would like to have that would work better for us.

Imagining thing we have never seen

Imagining thing we have never seen
Frank Wilson

There are lots of people now who think that children, in their early life experience, need to be allowed to play with objects in the real world to discover what the questions are. If we simply feed them the questions and say here’s the question, and here’s the answer; now you get it, what you do is you create a very robotic kind of cognition, I think, in which you discover later on that the imagination has really not developed.

The most difficult, for me, conceptual problem: If you think in terms of body-generated, body-movement-generated imagery, is how do we account for people’s ability to imagine things happening, when you can’t ever actually see them? For example, the idea of almost anything that goes on in particle physics having to do with the behavior of objects that you cannot and never will see. I remember—and, by the way, this is a big problem in teaching elementary science—how do you get kids to understand how an electric circuit works? How does an electromagnetic phenomenon work? It’s worth pointing out, I think, that in my own field of medicine, scientific medicine was being described as a worthy arrangement, a worthy foundation for what doctors did in the days of the Roman Empire. But, what ideas people had about how things actually worked in the Seventeenth Century, Francis Bacon and Rene Descartes were arguing over whether it was possible for objects at a distance to be attracted to one another. We’re now talking about the same thing. And, when William Harvey was talking about how the heart actually works, the question was, when it expands, is it creating a vacuum and drawing blood into the heart, or is it contracting and actually pushing the blood? It turns out that people were being excommunicated on the basis of which side of that question they were on.

So, we now talk about teaching children, for example, how things really work, we forget that there has been a struggle from the time of Aristotle to account for how it is that we experience the world. What is it in us that allows us to see and to analyze how things work, and how we use that in order to create systems; mechanical systems, physical systems architectural systems, if you will, that serve us in our daily lives. I have thought for a long time that it’s a problem if you put kids down in front of a computer screen and you give them somebody’s idea of how something works, and you skip the step in which they actually they actually play with the physical object. They don’t really understand what this intellectual struggle is all about. How do you set in mind a train of questions, set in action a train of questions about how the physical world works if you’ve never actually suddenly stumbled across a problem yourself in handling something. Why does a ball bounce a certain way? Why does another ball bounce a different way? Why when a juggler like Michael Motion throws a ball in a particular way does it now bounce away, but it comes back to you? How could that possibly be? There are lots of people now who think that children, in their early life experience, need to be allowed to play with objects in the real world to discover what the questions are. If we simply feed them the questions and say here’s the question, and here’s the answer; now you get it, what you do is you create a very robotic kind of cognition, I think, in which you discover later on that the imagination has really not developed. I am making a huge leap here in talking about this, but I do believe that even though you can’t make physical approximations of the way the world behaves all the time, it hasn’t been a problem for us to get where we are right now with a minimum of sort of artificial representation of how the world works and how we make inferences, how we do science, how we ask questions. But, I think children need to have that opportunity, and the body is a perfect laboratory for discovering what the questions in the physical world really are.

Embodied imagination

Embodied imagination
Frank Wilson

We don’t actually have to have seen all of these things in order to recognize them. We simply have to have a procedure by which we can mimic, or we can sort of pretend like this is what happened. In fact, there is a great deal of suggestive juice in this, that what we call visual imagery and imaginative imagery really depends upon a very complex process, which we know really pretty much nothing about.

There is a group in San Antonio who have been looking at the way what we refer to as visual imagery operates in the brain. The experiment, which is an ingenious experiment that was done that tells us that we are probably over simplifying how this works in a big way. It’s an experiment in which people are shown photographs of their own hand in different positions. They are very brief presentations on a computer screen. You see a brief flash; it is really only a fraction of a second that you see this. The question is asked, “Were you looking at your right hand or your left hand?” The experiment first demonstrated that what happens in this perceptual process involves a sort re-creational re-enactment of the rotation of your own hand into the position that you’re looking at, and it takes a certain amount of time. It takes more time to, let’s say, get your hand into this position then it does into this position, not a lot more time, but it’s measurable time.

It turns out that recognizing your own hand in a presentation in any particular rotation, that is recognizing that it is either the right hand or the left hand, is really time sensitive, and the time correlates match perfectly with the biomechanical correlates of rotating the hand into that position. So, the inference has been that what we think of as visual imagery, at least in terms of our own body, doesn’t depend upon some sort of card file in which we’ve to all of these pictures of our hand and we say oh, that’s this one that is labeled “left.” It’s that what we actually do is we very, very quickly reenact that movement, and then we say well that movement produces an image that matches with the image of my left hand when I did that. That’s how we actually make that decision.

It’s a very interesting concept to me because, to me, it is what I would call a psychologically generative system. We don’t actually have to have seen all of these things in order to recognize them. We simply have to have a procedure by which we can mimic, or we can sort of pretend like this is what happened. In fact, there is a great deal of suggestive juice in this, that what we call visual imagery and imaginative imagery really depends upon a very complex process, which we know really pretty much nothing about, but that involves the body sort of doing things and making things happen.

Now, when you gave an example earlier of Einstein looking at a compass, and there is a physical sense that one gets that there is something happening, and I wonder if I can make my body like that? People actually make judgements and they make imaginative leaps about how things really work based upon how they feel physically with the objects that are being manipulated.

The hand is like a crane.

The hand is like a crane.
Frank Wilson

The major project of waking life of a child between 6 and 12 months, is watching the hand handle objects. So, there is a calibration of visual feedback and manipulative, tactile, kinesthetic sense as the child is eagerly exploring the world that can be brought into physical contact and then controlled. So, controlling objects in the hand is a big deal and it’s a big part of what the child is doing, even lying there quietly or babbling, or just being awake and being given objects to handle.

The idea came gradually, but very naturally out of my experience in the medical practice in which, first of all, I understood that the muscles that allow you to complete a tight grip of this kind—the muscles that move the fingers aren’t in the hand at all; they are in the forearm. It is also manifestly clear that, in a way, the hand is like a crane. As with a crane, it has to be oriented in order to do what it needs to do. So, if you want to play the piano, you have your hand oriented in a position with the palm down. If you want to be holding a glass or lifting a glass or playing a saxophone, the hand is in this position, and on and on. The point is that the rest of the arm is clearly involved in positioning the hand in such a way that it can do what it is supposed to do. There is a lot of very, very complicated neurophysiology and developmental psychology that is devoted to understanding how children gain the ability, say, to shape the hand as it is moving toward an object to pick it up. How does the child, for example, blend what comes in through the eyes with what comes in through the muscle sense, what comes in through the tactile sense that is in the hand? These are processes that take literally years, but they start very early in life.

There is a group in England that had been working on visual, kinesthetic coordination, and I was told by a psychologist named Oliver Braddock, who was the chairman of the department of psychology at the university college of London, who is now at Oxford, that to put it very simply, the major project of waking life of a child between 6 and 12 months, is watching the hand handle objects. So, there is a calibration of visual feedback and manipulative, tactile, kinesthetic sense as the child is eagerly exploring the world that can be brought into physical contact and then controlled. So, controlling objects in the hand is a big deal and it’s a big part of what the child is doing, even lying there quietly or babbling, or just being awake and being given objects to handle.

Intelligence is not limited to intellect

Intelligence is not limited to intellect
Frank Wilson

Despite the fact that the process started probably five million years ago, it wasn’t really until about a hundred thousand years ago that archeologists tell us that the technology—and when I say “technology” I mean really beautifully designed tools for complicated tasks like stitching, creating fabrics, operating small handheld tools for a variety of reasons—the evidence that, that really became of force for the change of the circumstances of life, of small communities of people.

Interestingly enough, despite the fact that the process started probably five million years ago, it wasn’t really until about a hundred thousand years ago that archeologists tell us that the technology—and when I say “technology” I mean really beautifully designed tools for complicated tasks like stitching, creating fabrics, operating small handheld tools for a variety of reasons—the evidence that, that really became of force for the change of the circumstances of life, of small communities of people. We don’t know why it took so long for that to happen, because we know that stone tools were being manufactured and used regularly at least two million years ago. So, for the whole period of time of the process that led the doubling or tripling of the size of the human brain and its specialization for manipulating objects, during most of that time nothing was happening that produced any cultural artifacts that are of any real interest.

If you set that story aside and say that, that is enough time for the brain to have begun to learn how to accommodate the functional capacity that came into the hand. We know sort of look at the picture of individual child development. How do those two things map onto one another? I would like to tell the story that very early on after the publication of my book; I started going to book signings and book presentations at various places. Always, I was asked the question, “Well, if hands are so important to brain development, how come kids that don’t have hands or who have lost hands seem to do so well? What about the Thalidomide kids?” And, I said, “The way to look at that is you have to separate the long story—the evolutionary story—from the story of what we call ontology, which just means the development of the organism.” The way I look at it, and this is probably oversimplifying it terribly, is that the long story, the long evolutionary process produced a brain that was looking for a pair of hands. When the child is born, that child’s brain is going to start to animate hands—by the way, I’m a brand new grandfather, and this week my new granddaughter is three weeks old. Believe me, I’ve been looking at her hands and they are very busy. They are not capable of a lot of skill, yet, but they are in motion. It’s very interesting to come back to the child.

In the case of the Thalidomide babies, who turn out to be adults who can write with their toes and who can play musical instruments with their feet and their toes, and who can drive cars without any difficulty using their feet and their toes, is that if the brain doesn’t find a pair of hands, it will invent them. That’s what really happens. So, the developmental project for a young child is to bring the brain and the hand into a mutually reinforcing developmental process, around which what we call cognition and the sense of self that’s wrapped up in a body—and I’m just not much of a mind/body separatist. I think that you have to look at intelligence as being a function of the behavior of the entire organism. It’s not a new idea with me. I think if you just want to go and set up camp in the brain and look at what happens in the brain, that’s fine with me, but that has nothing to do with what we call human intelligence.

Use of the hand shaped the brain, language and culture

Use of the hand shaped the brain, language and culture
Frank Wilson

Cognitive scientists—even ones who are interested in child development—generally speaking, their interest is in the brain. But the brain is intimately connected to the hand.

Cognitive scientists—even ones who are interested in child development—generally speaking, their interest is in the brain. And, if you start talking about the hand, they will say, “Well, I know that the hand is very good in tool use and so forth, but you can see examples in other animals. Parrots can do this and chimpanzees can do that.” But, the fact of the matter is that for the most part, unless they have actually studied the upper extremity anatomically and in terms of its function; how grips are formed, how a child, for example, learns to control the frictional forces of an object that is slippery—unless they come to understand that and they really understand the details of it, they are simply going to gloss over the fact that, “Well, you know we have a long opposable thumb and we have the ability to independently control the movement of the digits, but you know, that’s not that different from what chimpanzees do.” And, I am here to tell you that it ain’t the same thing at all when you come to appreciate what the hand, biomechanically, is capable of doing and you look at the elaboration of complex human behavior; planning, thought, design, you driven to dig deeper and go further back. What you find when you go further back is that over millions of years subtle changes in the anatomy of the hand, the musculature of the hand, the joint structure of the hand created the possibility, mechanically, of manipulative acts that other animals—even the highest apes, the brightest chimps, Bonobo Chimps, the works, are not remotely capable of doing.

I was recently at a conference of cognitive psychologists in London, and I showed a video, just a very brief video of a chimpanzee being handed a small round object, about the size of a small walnut. The object goes into the hand; it rolls around in the hand and then it falls out. The chimp’s thumb is very small, and the fingers move parallel when they close into the hand. Now, they are very strong and they are very good moving in the up/down direction, but the animal is not capable of opposing the tips of the fingers, at all, to the thumb. Having shown that particular video, I showed the video of a nine or a ten-year-old kid, who is enrolled in a woodworking class at a school in Marin County. This is a school that tolerates the activities of a wonderful guy named Al Mayberry, who has been teaching carpentry to primary grade kids for over 25 years. [The students in] this sixth grade class were building dulcimers, and they were not out of kits. There is a long and fascinating story about this, but the point of the story here is that I showed a video clip to these psychologists in London, who are all eminent theoreticians. Here is the chimp trying to manage a little, round, irregular object rolling around in the hand, which it simply cannot hold, and here is a nine or a ten-year-old kid, who is stringing a dulcimer that he has just built, and the gasps in this audience were very refreshing to me to hear because it was clear that they hadn’t made the connection that this is from another planet, this kind of behavior. For me, now, the challenge has been and continues to be, first of all, to convince people that it isn’t a trivial matter that our hand and thumb are different and are capable of high-level skill. But the period of time . . . What is really important is helping people understand that all of the things that we associate with high-level human cognition can be traced to a long period of time during which the demand on the body and the mind for survival in a relatively small and otherwise defenseless animal really came depend upon what it was able to do with its hands in an environment that was full of predators.

The Developing Brain Part Four

Marian C. Diamond, PhD. - The Constantly Adapting Brain

Marian C. Diamond, Ph.D, a neuroscientist at U.C Berkeley did research on the neuroanatomy of the forebrain, notably the impact of the environment on brain development, published under the title Enriching Heredity: The Impact of the Environment on the Anatomy of the Brain. Marian describes how rich interaction with the environment literally grows and shapes the brain lifelong. “There are a hundred billion nerve cells in a brain and many of those nerve cell can make connections with thousands of others. A single nerve cell can receive as much input from about 20,000 other cells, so you think of the computation that goes on in a single cell before it fires. The interaction of the environment with this system is extremely dynamic and important. One can say that the brain is responding to the external environment and to the internal environment at all times. The nerve cells are designed to receive stimuli, store information and transmit information.  Every cell receives input from both the internal and the external environment at all times.  And we've shown that we can (physically) change the brain by changing the internal and external environments at any age.”

Themes: 
brain
brain development
child development

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