Mihaly Csikszentmihalyi on flow

The Artist's way

Dependence on the creator within is really freedom from all other dependencies

Lecture 7 - Conscious of the Present; Conscious of the Past: Language (cont.); Vision and Memory

Overview:

This lecture finishes the discussion of language by briefly reviewing two additional topics: communication systems in non-human primates and other animals, and the relationship between language and thought. The majority of this lecture is then spent on introducing students to major theories and discoveries in the fields of perception, attention and memory. Topics include why we see certain visual illusions, why we don't always see everything we think we see, and the relationship between different types of memory.



And in the course of this I want to make a series of claims that go something like this. For perception, I want to first persuade you the problem of perception's hard and that successful perception involves educated and unconscious guesses about the world. For attention, I want to suggest that we attend to some things and not others and we miss a surprising amount of what happens in the world. For memory, there are many types of memory. The key to memory is organization and understanding. And you can't trust some of your memories.
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There is a story--I went to graduate school at MIT and there was a story there about Marvin Minsky who is the A.I. [artificial intelligence] guru. He--If you've heard the words--the phrase "artificial intelligence," that was him. And if you heard the claim that people are nothing more than machines made of meat--also him. Well, there's a story where he was doing work on robotics and he was interested in building a robot that could do all sorts of cool things that's like a robot. And the story goes the robot had to among--had to write--had to see the world. It had to be able to pick up things and recognize people and see chairs and navigate its way and Minsky said, "That's a tough problem. It's going to take a graduate student a whole summer to figure it out." And he assigned it to a graduate student for a summer project.

Visual psychologists, perception psychologists, love that story because the study of computer vision and robotics vision and the attempts to make machines that can identify and recognize objects has been a profound failure. There is, at this point, no machine on earth that could recognize people and objects and things at the level of a really dumb one-year-old. And the reason why is that it's a much harder problem than anybody could have expected. Well, what makes it such a hard problem?

Well, one reason why you might think it's an easy problem is you say, "Okay. We have to figure out the problem of how people see. Well, here's what we do." [pointing to a slide that caricatures the inside of a person's head as containing a little man, the real "you," sitting in a control room watching a television monitor that is connected to the larger-head's eyeballs] You're in--You're over there and here's your eye. And somehow it has to get to this television monitor and then you look at it and that'll solve the problem of how you see. So, sometimes people say, "Hey. I hear the eye flips things upside down. I guess this guy [the guy in your head] is going to have to get used to looking at things upside down. That's an interesting problem." No. That's not the way to look at it because that doesn't answer any questions. That just pushes the question back. Fine. How does "he" see? We're not answering anything.

Here's the right way to think about perception. You got the eye, which is very ugly and bloody, and then around here you have the retina. And the retina is a bunch of nerve cells. And the nerve cells fire at--for some stimulus and not others. And from this array of firings, "firing… not firing… firing… not firing," you have to figure out what the world is. So, a better view is like this. The firings of the neurons could be viewed as an array of numbers. You have to figure out how to get from the numbers to objects and people, and to actions and events. And that's the problem. It's made particularly a difficult problem because the retina is a two-dimensional surface and you have to infer a 3D world from a two-dimensional surface. And this is, from a mathematical point of view, impossible. And what this means is that there--For any two-dimensional image there is an indefinite number of three-dimensional images that correspond to it.

So for instance, suppose you have this on your retina, an array of light shaped like that [referring to a slide portraying a square and an irregular polygon that could be a square that is tilted backwards in space]. What does that correspond to in the world? Well, it could correspond to a thing just like that that you're looking for or it could correspond to a square that's tilted backwards. And so, you have to figure out which is which. And the way we solve this problem is that we have unconscious assumptions about how the world works. Our minds contain certain assumptions about how things should be that enable us to make educated guesses from the two-dimensional array on to the three-dimensional world.
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First, the problem of color. How do you tell a lump of coal from a snowball? Well, that's a lump of coal and that's a snowball, and it's from Google images. How do you know which is which? Well, a lump of coal you say is black and a snowball is white. How do you know? Well, maybe you have on your retina--Your retina responds to sort of color that hits it. It's oversimplified, but let's assume that this is true. So, this is black coming out and that's white and that's how you tell. But in fact, that can't be right. It can't be right because objects' color is not merely a matter of what material they're made of but of the amount of light that hits it. So, as I walk across the stage I fall into shadow and light, and none of you screams out, "Professor Bloom is changing colors!" Rather, you automatically factor out the change in illumination as this is happening.
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He was a world-renowned choir director and he suffered viral encephalitis which led to brain damage which destroyed most of his temporal lobes, his hippocampus, and a lot of his left frontal lobe. It could be--It could have been worse in that he retains the ability to talk. He seems to be--He's not intellectually impaired. He just can't form new memories and so he lives in this perpetual "now" where just nothing affects him and he feels--This has not always happened. There's more than one of these cases and it doesn't always happen like this, but he feels continually reborn at every moment. And we'll return to this and then ask what's going on here. But there's a few themes here.

I want to, before getting into detail about memory, I want to review some basic distinctions in memory when we talk about memory. So crudely, you could make a distinction between sensory memory, short-term memory, which is also known as working memory, and long-term memory. Sensory memory is a residue in your senses. There's a flash of lightning. You might see an afterimage. That afterimage is your sensory memory. There's somewhat of a longer echoic memory for sounds. So as somebody is talking to you even if you're not paying attention you'll store a few seconds of what they're saying, which is sometimes, when somebody's talking to you and you're not listening to them and they say, "You're not listening to me." And you say, "No. You were talking about--" and pick up the last couple of seconds from echoic memory. There's short-term memory.

Anybody remember what I just said? If you did, that's short-term memory--spans for a few minutes. And then there's long-term memory. Anybody know who Elvis is? Do you know your name? Do you know where you live? Your long-term memory store that you walk around with and you're not going to lose right away. When we think about amnesia in the movie sense, we think of a certain loss of long-term memory associated with autobiographical personal events.

There is a distinction between implicit and explicit, which we'll talk about it in more detail. But explicit, crudely, is what you have conscious access to. So, what you had for dinner last night. You could think back and say, "I had this for dinner last night." Implicit is more unconscious. What the word--what certain word--what the word "had" means, how to walk, how to ride a bicycle, that you might not be able to articulate and might not even be conscious of but still have access to.

There's a distinction between semantic memory and episodic memory. Semantic memory is basically facts, what a word means, what's the capital of Canada, and so on. Episodic is autobiography, is what happened to you. That Yale is in New Haven is semantic. That you went on vacation away from New Haven last week, it would be episodic. There is encoding stores and retrieval, which refers to different levels of what happens in memory. Encoding is getting the memory in, as when you study for a test or you have an experience. And storage is holding the memory. And retrieval is getting the memory out.

Lecture 6 - How Do We Communicate?: Language in the Brain, Mouth and the Hands

Overview:

One of the most uniquely human abilities is the capacity for creating and understanding language. This lecture introduces students to the major topics within the study of language: phonology, morphology, syntax and recursion. This lecture also describes theories of language acquisition, arguments for the specialization of language, and the commonalities observed in different languages across cultures.




I began this class with a demonstration of--that illustrates two very important facts about language. One is that languages all share some deep and intricate universals. In particular, all languages, at minimum, are powerful enough to convey an abstract notion like this; abstract in the sense that it talks about thoughts and it talks about a proposition and spatial relations in objects. There's no language in the world that you just cannot talk about abstract things with. Every language can do this. But the demonstration [before class] also illustrated another fact about language, which is how different languages are. They sound different. If you know one language, you don't necessarily know another. It's not merely that you can't understand it. It could sound strange or look unusual in the case of a sign language. And so, any adequate theory of language has to allow for both the commonalities and the differences across languages. And this is the puzzle faced by the psychology and cognitive science of language.

Well, let's start with an interesting claim about language made by Charles Darwin. So, Darwin writes, "Man has an instinctive tendency to speak, as we see in the babble of our young children, while no child has an instinctive tendency to bake, brew or write." And what Darwin is claiming here, and it's a controversial and interesting claim, is that language is special in that there's some sort of propensity or capacity or instinct for language unlike the other examples he gives. Not everything comes natural to us but Darwin suggests that language does.

Well, why should we believe this? Well, there are some basic facts that support Darwin's claim. For one thing, every normal--every human society has language. In the course of traveling, cultures encounter other cultures and they often encounter cultures that are very different from their own. But through the course of human history, nobody has ever encountered another group of humans that did not have a language. Does this show that it's built in? Well, not necessarily. It could be a cultural innovation. It could be, for instance, that language is such a good idea that every culture comes across it and develops it. Just about every culture uses some sort of utensils to eat food with, a knife and a fork, chopsticks, a spoon. This probably is not because use of eating utensils is human nature, but rather, it's because it's just a very useful thing that cultures discover over and over again. Well, we know that this probably is not true with regard to language. And one reason we know this is because of the demonstrated case studies where a language is created within a single generation. And these case studies have happened over history.

The standard example is people involved in the slave trade. The slave trade revolving around tobacco or cotton or coffee or sugar would tend to mix slaves and laborers from different language backgrounds, in part deliberately, so as to avoid the possibility of revolt. What would happen is these people who were enslaved from different cultures would develop a makeshift communication system so they could talk to one another. And this is called a "pidgin," p-i-d-g-i-n, a pidgin. And this pidgin was how they would talk. And this pidgin was not a language. It was strings of words borrowed from the different languages around them and put together in sort of haphazard ways.

The question is what happens to the children who are raised in this society. And you might expect it that they would come to speak a pidgin, but they don't. What happens is, in the course of a single generation, they develop their own language. They create a language with rich syntax and morphology and phonology, terms that we'll understand in a few minutes. And this language that they create is called a "creole." And languages that we know now as creoles, the word refers back to their history. That means that they were developed from pidgins. And this is interesting because this suggests that to some extent the ability to use and understand and learn language is part of human nature. It doesn't require an extensive cultural history. Rather, just about any normal child, even when not exposed to a full-fledged language, can create a language.

And more recently, there's been case studies of children who acquire sign language. There's a wonderful case in Nicaragua in sign language where they acquire sign language from adults who themselves are not versed in sign language. They're sort of second-language learners struggling along. What you might have expected would be the children would then use whatever system their adults use, but they don't. They "creolized" it. They take this makeshift communication system developed by adults and, again, they turn it into a full-blown language, suggesting that to some extent it's part of our human nature to create languages.

Also, every normal human has language. Not everybody in this room can ride a bicycle. Not everybody in this room can play chess. But everybody possesses at least one language. And everybody started to possess at least one language when they were a child. There are exceptions, but the exceptions come about due to some sort of brain damage. Any neurologically normal human will come to possess a language.

What else do we know? Well, the claim that language is part of human nature is supported by neurological studies, some of which were referred to in the chapters on the brain that you read earlier that talk about dedicated parts of the brain that work for language. And if parts of these brains--if parts--if these parts of the brain are damaged you get language deficits or aphasias where you might lose the ability to understand or create language. More speculatively, there has been some fairly recent work studying the genetic basis of language, looking at the genes that are directly responsible for the capacity to learn and use language. And one bit of evidence that these genes are implicated is that some unfortunate people have point mutations in these genes. And such people are unable to learn and use language.
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Morphology is the next level up. Phonology is sounds. Morphology is words. And human language uses this amazing trick described by Ferdinand de Saussure, the great linguist, as "the arbitrariness of the sign." And what this means is we can use--take any arbitrary idea in the world, the idea of a chair or a story or a country, and make a sound or a sign to connect to it. And the link is arbitrary. You might choose to use a word for "dog" as "woof woof" because it sounds like a dog but you can't use a word for "country" that sounds like a country. You could use a sign language thing for "drink" that looks sort of like the act of drinking but you can't use a sign language word for "country" that looks like a country, or for "idea" that looks like an idea.

So, the way languages work is it allows for arbitrary naming. It allows for this map between a symbol, say a spoken word, and any sort of thought we want to use. And those arbitrary mappings, as we come to learn them, make up the vocabulary of a language. I'm talking about words but the more technical term is "morpheme." And what a morpheme is is the smallest meaningful unit in a language. Now often, this is the same thing as a word. So, "dog" is a word. And "dog" is also a morpheme, but not always because there are single morphemes and then there are words that are composed of many morphemes. So, "dogs" and "complained" are one word, but two morphemes and what this means is that you make the word by putting together two morphemes. To put it differently, in order to know what "dogs" means, you never had to learn the word "dogs." All you had to know is the word "dog" and the plural morpheme 's' and you could put them together to create a word.

How many morphemes does the average speaker know? The answer is fairly startling. The average speaker knows, as a low-ball estimate, about 60,000 words. I think the proper estimate is closer to 80,000 or 100,000. What this means, if you average it out, is that since children start learning their first words at about their first year of life, they learn about nine new words a day. And it's not a continuous nine words every day. It goes up and down depending on the age. But still, the amount of words we know is staggering. How many of you know more than one language pretty fluently? Those of you who know other languages might have in your heads 200,000 words or 300,000 words and you're accessing them in a fraction of a second. It is--could legitimately be seen as one of the most astonishing things that people do.
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One of the real surprising findings in my field over the last ten/twenty years has been that the acquisition of sign languages has turned out to be almost exactly the same; in fact, as far as we know, exactly the same as the acquisition of spoken languages. It didn't have to be that way. It could have been just as reasonable to expect that there'd be an advantage for speech over sign. That sign languages may be full-blown languages but they just take--they're just harder to learn because the brain and the body have adapted for speech. It turns out that this just isn't the case. It turns out that sign and--the developmental milestones of sign languages and the developmental milestones of spoken languages are precisely the same. They start babbling at the same point. They start using first words, first sentences, first complicated constructions. There seems to be no interesting difference between how the brain comes to acquire and use the spoken language versus a sign language.

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Lecture 5 - What Is It Like to Be a Baby: The Development of Thought

Overview:

This lecture explores issues and ideas related to the branch of psychology known as cognitive development. It begins with an introduction of Piaget who, interested in the emergence of knowledge in general, studied children and the way they learn about the world in order to formulate his theories of cognitive development. This is followed by an introduction to the modern science of infant cognition. Finally, the question of the relationship between and the existence of different kinds of development is addressed.



Now, this research suggests that infants' understanding of the physical world is there from the very start, but at the same time not entirely. We know there are certain things babies don't know. Here's an example. Suppose you show babies this. You have a block here and then you have something above there floating in mid air. Babies find this surprising. Even six-month-olds find this surprising. It violates gravity, but six-month-olds aren't smart enough to know that a block just stuck over here is also surprising. Twelve-month-olds will think that it should fall. Six-month-olds don't, and even 12-month-olds don't find anything weird about this, while adults are sophisticated enough to understand that that's an unstable configuration and should fall over. So, although some things are built in, some things develop.

And this raises the question of, "How do we explain development?" How do we explain when babies come to know things that they didn't originally know? Well, one answer is neural maturation, growth of the brain. Most of the neurons you have now in your head, right now, you had when you were in your mother's uterus. What happens in development isn't for the most part the growth of new neurons. It's for the most part pruning, getting rid of neurons. So, the neural structures change radically as babies kind of get rid of excess neurons through development. At the same time though, connections between neurons grow like crazy and they--and this process of synaptic growth where there are the connections across different synapses peaks at about two years. Finally, remember myelination, where you sort of get this fatty sheath over your neuron to make it more effective? That also happens through development, and in fact, it goes through development and even teenagers are not fully myelinated. In particular, they're not fully myelinated in their frontal lobes. Recall that frontal lobes are involved in things like restraint and willpower. And so, it could be the problem is the baby's brain doesn't develop yet.
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Another interesting area of debate is, "What's the relationship between different sorts of development?" So, I started off with Piaget, and Piaget, like Freud, believed in general, across the board changes in how children think. An alternative, though, is that there's separate modules, and this is a view developed, again, by Noam Chomsky, and also by the philosopher of mind Jerry Fodor, who claimed that the whole idea of a child developing as a single story is mistaken. What you get instead is there are separate pre-wired systems for reasoning about the world. These systems have some built-in knowledge, and they have to do some learning, but the learning pattern varies from system to system and there's a separateness to them. Why should we take this view seriously? Well, one reason is that there are developmental disorders that seem to involve damage to one system but not to another. And the classic case of this is a disorder known as autism. And autism is something I've always found a fascinating disorder for many reasons. It's actually why I entered psychology. I started off working with children with autism. And it could be taken as a striking illustration of how the social part of your brain is distinct from other parts of your brain.

So, what autism is is a disorder that strikes about one in a thousand people, mostly boys. And the dominant problems concern--consist of a lack of social connectedness, problems with language, problems dealing with people, and more generally, a problem of what the psychologist, Simon Baron-Cohen has described as "mind blindness." In that autistic people show no impairments dealing with the physical world, they show no impairments on--they don't necessarily show any impairments on mathematical skills or spatial skills, but they have a lot of problems with people. Now, many autistic children have no language; they're totally shut off from society. But even some of them who'd learned language and who managed to get some sort of independent life, nevertheless will suffer from a severe social impairment. And this could be shown in all sorts of ways.

A simple experiment developed by Simon Baron-Cohen goes like this. You show this to three- and four-year-olds. There's four candies there, and you say, "This is Charlie in the middle. Which chocolate will Charlie take?" For most children and most of you, I hope, the answer's pretty clear: This one. Autistic children will often just shrug, say, "How could I know?" because they don't instinctively appreciate that people's interests and desires tend to be attuned to where they're looking.

Another sort of task, which is a task that's been done hundreds, perhaps thousands of times, is known as "the false-belief task" and here's the idea. You show the child the following situation. There's a doll named Maxie and Maxie puts the ball in the cupboard. Maxie leaves and a second doll enters. The second doll takes the ball out of the cupboard and puts it under the bed. Maxie comes back and the question is, "Where will Maxie look for the ball?" Now, this is a question about your understanding about minds. The question of where is the ball really is a question about the physical world. Everyone can solve it, but this question is hard. The right answer is Max will--Maxie will look in the cupboard, even though it's not really there because Maxie has a false belief about the world. Three-year-olds find this difficult. Two-year-olds find this difficult. Four-year-olds and five-year-olds are able to pass this task. Normal adults are able to pass this task. Children with autism have serious problems. And often, people with autism who are otherwise very high functioning will fail this task. They'll say, "Oh, he must think it's not--He'll--He's going to check under the bed." Any questions about autism? Yes.
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Another question is if you believe in modules--If there are modules, what are they? And so far when reviewing the developmental data we've talked about two of them: physics and people. An object module and a social module. But other people have argued that there is a special module in your brain for dealing with artifacts, that is, things like tables and chairs and cars and forks. Some people have argued there's a module for sociology, for dealing with human groups, races and classes and so on. Some have even argued that there is an intuitive biology, a common-sense biological understanding of the world that's separate from your understanding of people and physics. And, in fact, the most dominant proponent of the view is our very own Frank Keil, Master of Morse College at Yale, who has strongly defended the notion of an intuitive biological module.

Final question, just to raise: I've talked in terms of the modular view but there might also be profound general differences between children and adults, not just specific to how you think about objects or how you think about people or how you think about this or how you think about that, but rather more general. And one claim, which we're going to return to briefly next class when we talk about language, is that there's a very, very big difference between a creature that doesn't have language and a creature that does. And part of the claim is that learning a language, learning to speak, reconfigures the human brain in such a way that is really exceptional. And that has no parallel in any other species. And this is an interesting claim and one we'll talk about.

Lecture 4 - Foundations: Skinner

Overview:

Professor Bloom opens with a brief discussion of the value and evolutionary basis of unconscious processing. The rest of this lecture introduces students to the theory of Behaviorism, particularly the work of prominent behaviorist, B. F. Skinner. Different types of learning are discussed in detail, as well as reasons why behaviorism has been largely displaced as an adequate theory of human mental life.



Professor Paul Bloom: I actually want to begin by going back to Freud and hitting a couple of loose ends. There was a point in my lecture on Wednesday where I skipped over some parts. I said, "We don't have time for this" and I just whipped past it. And I couldn't sleep over the weekend. I've been tormented. I shouldn't have skipped that and I want to hit--Let me tell you why I skipped it. The discussion I skipped was the discussion of why we would have an unconscious at all. So, I was talking about the scientifically respectable ideas of Freud and I want to talk about some new ideas about why there could be an unconscious.

Now, the reason why I skipped it is I'm not sure this is the best way to look at the question. As we will learn throughout the course, by far the vast majority of what our brains do, the vast majority of what our minds do, is unconscious and we're unaware of it. So the right question to ask may not be, "Why are some things unconscious?" but rather, why is this tiny subset of mental life--why is this conscious? On the other hand, these claims about the utility of unconsciousness, I think, are provocative and interesting. So I just wanted to quickly share them with you.

So, the question is, from an evolutionary standpoint, "Why would an unconscious evolve?" And an answer that some psychologists and biologists have given is deception. So, most animals do some deception. And deception defined broadly is simply to act or be in some way that fools others into believing or thinking or responding to something that's false.

There's physical examples of deception. When threatened, chimpanzees--their hair stands up on end and that makes them look bigger to fool others to thinking they're more dangerous than they are. There's an angler fish at the bottom of the ocean that has a rod sticking up from the top of its head with a lure to capture other fish – to fool them in thinking that this is something edible and then to themselves be devoured. But humans, primates in general but particularly humans, are masters of deception. We use our minds and our behaviors and our actions continually to try to trick people into believing what's not true. We try to trick people, for instance, into believing that we're tougher, smarter, sexier, more reliable, more trustworthy and so on, than we really are. And a large part of social psychology concerns the way in which we present ourselves to other people so as to make the maximally positive impression even when that impression isn't true.

At the same time, though, we've also evolved very good lie detection mechanisms. So not only is there evolutionary pressure for me to lie to you, for me to persuade you for instance, that if we're going to have a--if you are threatening me don't threaten me, I am not the sort of man you could screw around with. But there's evolutionary pressure for you to look and say, "No. You are the sort of man you could screw around with. I can tell." So how do you become a good liar? And here's where the unconscious comes in. The hypothesis is: the best lies are lies we tell ourselves. You're a better liar, more generally, if you believe the lie that you're telling.

This could be illustrated with a story about Alfred Hitchcock. The story goes--He hated working with child actors but he often had to. And the story goes--He was dealing with a child actor who simply could not cry. And, finally frustrated, Hitchcock went to the actor, leaned over, whispered in his ear, "Your parents have left you and they're never coming back." The kid burst into tears. Hitchcock said, "Roll ‘em" and filmed the kid. And the kid, if you were to see him, you'd say, "That's--Boy, he's--he really looks as if he's sad" because he was. If I had a competition where I'd give $100,000 to the person who looks the most as if they are in pain, it is a very good tactic to take a pen and jam it into your groin because you will look extremely persuasively as if you are in pain. If I want to persuade you that I love you, would never leave you, you can trust me with everything, it may be a superb tactic for me to believe it. And so, this account of the evolution of the unconscious is that certain motivations and goals, particularly sinister ones, are better made to be unconscious because if a person doesn't know they have them they will not give them away. And this is something I think we should return to later on when we talk about social interaction and social relationships.
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Now, at the core of behaviorism are three extremely radical and interesting views. The first is a strong emphasis on learning. The strong view of behaviorism is everything you know, everything you are, is the result of experience. There's no real human nature. Rather, people are infinitely malleable. There's a wonderful quote from John Watson and in this quote John Watson is paraphrasing a famous boast by the Jesuits. The Jesuits used to claim, "Give me a child until the age of seven and I'll show you the man," that they would take a child and turn him into anything they wanted. And Watson expanded on this boast,

Give me a dozen healthy infants, well-formed and my own specified world to bring them up and I'll guarantee to take any one at random and train them to become any type of specialist I might select--doctor, lawyer, artist, merchant, chief, and yes, even beggar-man and thief, regardless of his talents, penchants, tendencies, abilities, vocations and race of his ancestors.

Now, you could imagine--You could see in this a tremendous appeal to this view because Watson has an extremely egalitarian view in a sense. If there's no human nature, then there's no sense in which one group of humans by dint of their race or their sex could be better than another group. And Watson was explicit. None of those facts about people will ever make any difference. What matters to what you are is what you learn and how you're treated. And so, Watson claimed he could create anybody in any way simply by treating them in a certain fashion.

A second aspect of behaviorism was anti-mentalism. And what I mean by this is the behaviorists were obsessed with the idea of doing science and they felt, largely in reaction to Freud, that claims about internal mental states like desires, wishes, goals, emotions and so on, are unscientific. These invisible, vague things can never form the basis of a serious science. And so, the behaviorist manifesto would then be to develop a science without anything that's unobservable and instead use notions like stimulus and response and reinforcement and punishment and environment that refer to real world and tangible events.

Finally, behaviorists believed there were no interesting differences across species. A behaviorist might admit that a human can do things that a rat or pigeon couldn't but a behaviorist might just say, "Look. Those are just general associative powers that differ" or they may even deny it. They might say, "Humans and rats aren't different at all. It's just humans tend to live in a richer environment than rats." From that standpoint, from that theoretical standpoint, comes a methodological approach which is, if they're all the same then you could study human learning by studying nonhuman animals. And that's a lot of what they did.
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Okay. So, here are the three general positions of behaviorism. (1) That there is no innate knowledge. All you need is learning. (2) That you could explain human psychology without mental notions like desires and goals. (3) And that these mechanisms apply across all domains and across all species. I think it's fair to say that right now just about everybody agrees all of these three claims are mistaken.

First, we know that it's not true that everything is learned. There is considerable evidence for different forms of innate knowledge and innate desires and we'll look--and we'll talk about it in detail when we look at case studies like language learning, the development of sexual preference, the developing understanding of material objects. There's a lot of debate over how much is innate and what the character of the built-in mental systems are but there's nobody who doubts nowadays that a considerable amount for humans and other animals is built-in.

Is it true that talking about mental states is unscientific? Nobody believes this anymore either. Science, particularly more advanced sciences like physics or chemistry, are all about unobservables. They're all about things you can't see. And it makes sense to explain complex and intelligent behavior in terms of internal mechanisms and internal representations. Once again, the computer revolution has served as an illustrative case study. If you have a computer that plays chess and you want to explain how the computer plays chess, it's impossible to do so without talking about the programs and mechanisms inside the computer.

Is it true that animals need reinforcement and punishment to learn? No, and there's several demonstrations at the time of Skinner suggesting that they don't. This is from a classic study by Tolman where rats were taught to run a maze. And what they found was the rats did fine. They learn to run a maze faster and faster when they're regularly rewarded but they also learn to run a maze faster and faster if they are not rewarded at all. So the reward helps, but the reward is in no sense necessary.
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Finally, the other reading you're going to do for this part--section of the course is Chomsky's classic article, his "Review of Verbal Behavior." Chomsky is one of the most prominent intellectuals alive. He's still a professor at MIT, still publishes on language and thought, among other matters. And the excerpt you're going to read is from his "Review of Verbal Behavior." And this is one of the most influential intellectual documents ever written in psychology because it took the entire discipline of behaviorism and, more than everything else, more than any other event, could be said to have destroyed it or ended it as a dominant intellectual endeavor.

And Chomsky's argument is complicated and interesting, but the main sort of argument he had to make is--goes like this. When it comes to humans, the notions of reward and punishment and so on that Skinner tried to extend to humans are so vague it's not science anymore. And remember the discussion we had with regard to Freud. What Skinner--What Chomsky is raising here is the concern of unfalsifiablity. So, here's the sort of example he would discuss. Skinner, in his book Verbal Behavior, talks about the question of why do we do things like talk to ourselves, imitate sounds, create art, give bad news to an enemy, fantasize about pleasant situations? And Skinner says that they all involve reinforcement; those are all reinforced behaviors. But Skinner doesn't literally mean that when we talk to ourselves somebody gives us food pellets. He doesn't literally mean even that when we talk to ourselves somebody pats us on the head and says, "Good man. Perfect. I'm very proud." What he means, for instance, in this case is well, talking to yourself is self-reinforcing or giving bad news to an enemy is reinforcing because it makes your enemy feel bad.

Well, Chomsky says the problem is not that that's wrong. That's all true. It's just so vague as to be useless. Skinner isn't saying anything more. To say giving bad news to an enemy is reinforcing because it makes the enemy feel bad doesn't say anything different from giving bad news to an enemy feels good because we like to give bad news to an enemy. It's just putting it in more scientific terms.

More generally, Chomsky suggests that the law of effect when applied to humans is either trivially true, trivially or uninterestingly true, or scientifically robust and obviously false. So, if you want to expand the notion of reward or reinforcement to anything, then it's true. So why did you come--those of you who are not freshmen--Oh, you--Why did you come? All of you, why did you come to Yale for a second semester? "Well, I repeated my action because the first semester was rewarding." Okay. What do you mean by that? Well, you don't literally mean that somebody rewarded you, gave you pellets and stuff. What you mean is you chose to come there for the second semester. And there's nothing wrong with saying that but we shouldn't confuse it with science. And more generally, the problem is you can talk about what other people do in terms of reinforcement and punishment and operant conditioning and classical conditioning. But in order to do so, you have to use terms like "punishment" and "reward" and "reinforcement" in such a vague way that in the end you're not saying anything scientific.

So, behaviorism as a dominant intellectual field has faded, but it still leaves behind an important legacy and it still stands as one of the major contributions of twentieth century psychology. For one thing, it has given us a richer understanding of certain learning mechanisms, particularly with regard to nonhumans. Mechanisms like habituation, classical conditioning and operant conditioning are real; they can be scientifically studied; and they play an important role in the lives of animals and probably an important role in human lives as well. They just don't explain everything. Finally, and this is something I'm going to return to on Wednesday actually, behaviorists have provided powerful techniques for training particularly for nonverbal creatures so this extends to animal trainers. But it also extends to people who want to teach young children and babies and also want to help populations like the severely autistic or the severely retarded. Many of these behaviorist techniques have proven to be quite useful. And in that regard, as well as in other regards, it stands as an important contribution.

Lecture 3 - Foundations: Freud

Overview:

This lecture introduces students to the theories of Sigmund Freud, including a brief biographical description and his contributions to the field of psychology. The limitations of his theories of psychoanalysis are covered in detail, as well as the ways in which his conception of the unconscious mind still operate in mainstream psychology today.



Now, if that's the sort of thing you know about Freud, you are not going to have a very high opinion of him or of his work, but at the core of Freud's declamation, the more interesting ideas, is a set of claims of a man's intellectual importance. And the two main ones are this. The two main ones involve the existence of an unconscious, unconscious motivation, and the notion of unconscious dynamics or unconscious conflict which lead to mental illnesses, dreams, slips of the tongue and so on.

The first idea – the idea of unconscious motivation – involves rejecting the claim that you know what you're doing. So, suppose you fall in love with somebody and you decide you want to marry them and then somebody was asked to ask you why and you'd say something like, "Well, I'm ready to get married this stage of my life; I really love the person; the person is smart and attractive; I want to have kids" whatever. And maybe this is true. But a Freudian might say that even if this is your honest answer – you're not lying to anybody else –still, there are desires and motivations that govern your behavior that you may not be aware of. So, in fact, you might want to marry John because he reminds you of your father or because you want to get back at somebody for betraying you.
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Now, all of this would be fine if your unconscious was a reasonable, rational computer, if your unconscious was really smart and looking out for your best interest. But, according to Freud, that's not the way it works. According to Freud, there are three distinct processes going on in your head and these are in violent internal conflict. And the way you act and the way you think are products, not of a singular rational being, but of a set of conflicting creatures. And these three parts are the id, the ego, and the superego and they emerge developmentally.

The id, according to Freud, is present at birth. It's the animal part of the self. It wants to eat, drink, pee, poop, get warm, and have sexual satisfaction. It is outrageously stupid. It works on what Freud called, "The Pleasure Principle." It wants pleasure and it wants it now. And that's, according to Freud, how a human begins – pure id. Freud had this wonderful phrase, "polymorphous perversity," this pure desire for pleasure.

Now, unfortunately, life doesn't work like that. What you want isn't always what you get and this leads to a set of reactions to cope with the fact that pleasure isn't always there when you want it either by planning how to satisfy your desires or planning how to suppress them. And this system is known as the ego, or the self. And it works on the "Reality Principle." And it works on the principle of trying to figure out how to make your way through the world, how to satisfy your pleasures or, in some cases, how to give up on them. And the ego – the emergence of the ego for Freud--symbolizes the origin of consciousness.

Finally, if this was all there it might be a simpler world, but Freud had a third component, that of the superego. And the superego is the internalized rules of parents in society. So, what happens in the course of development is, you're just trying to make your way through the world and satisfy your desires, but sometimes you're punished for them. Some desires are inappropriate, some actions are wrong, and you're punished for it. The idea is that you come out; you get in your head a superego, a conscience. In these movies, there'd be a little angel above your head that tells you when things are wrong. And basically your self, the ego, is in between the id and the superego.

One thing to realize, I told you the id is outrageously stupid. It just says, "Oh, hungry, food, sex, oh, let's get warm, oh." The superego is also stupid. The superego, point to point, is not some brilliant moral philosopher telling you about right and wrong. The superego would say, "You should be ashamed of yourself. That's disgusting. Stop doing that. Oh." And in between these two screaming creatures, one of you; one of them telling you to seek out your desires, the other one telling you, "you should be ashamed of yourself," is you, is the ego.

Now, according to Freud, most of this is unconscious. So, we see bubbling up to the top, we feel, we experience ourselves. And the driving of the id, the forces of the id and the forces of the superego, are unconscious in that we cannot access them. We don't know what--It's like the workings of our kidneys or our stomachs. You can't introspect and find them. Rather, they do their work without conscious knowledge.
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And the problems with Freud go like this. There are two ways you could reject a theory. There are two problems with the scientific theory. One way you could reject a theory is that it could be wrong. So, suppose I have a theory that the reason why some children have autism, a profound developmental disorder, is because their mothers don't love them enough. This was a popular theory for many years. It's a possible theory. It just turns out to be wrong but another way--And so one way to attack and address a scientific theory is to view it as just to see whether or not it works. But there's a different problem a theory could have. A theory could be so vague and all encompassing that it can't even be tested. And this is one of the main critiques of Freud. The idea could be summed up by a quotation from the physicist Wolfgang Pauli. And Pauli was asked his opinion about another physicist. And Pauli said this: "That guy's work is crap. He's not right. He's not even wrong." And the criticism about Freud is that he's not even wrong.

The issue of vagueness is summarized in a more technical way by the philosopher Karl Popper who described--who introduced the term of falsifiability. The idea of falsifiability is that what distinguishes science from non science is that scientific predictions make strong claims about the world and these claims are of a sort that they could be proven wrong. If they couldn't be proven wrong, they're not interesting enough to be science. So, for example, within psychology the sort of claims we'll be entertaining throughout the course include claims like, damage to the hippocampus causes failures of certain sorts of memory, or everywhere in the world men on average want to have more sexual partners than women, or exposure to violent television tends to make children themselves more violent. Now, are they true or are they false? Well, we'll talk about that, but the point here is they can be false. They're interesting enough that they can be tested and as such they go to--they might be wrong but they graduate to the level of a scientific theory.
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Now, there's one question. I'm actually going to skip over this for reasons of time and just go to some examples of the unconscious in modern psychology. So, here's a simple example of the unconscious in modern psychology: Language understanding. So, when you hear a sentence like, "John thinks that Bill likes him," in a fraction of a second you realize that this means that John thinks that Bill likes John. If you heard the sentence--Oops--"John thinks that Bill likes himself," in a fraction of a second you would think that it means "John thinks that Bill likes Bill." And as we will get to when we get to the lecture on language, this is not conscious. You don't know how you do this. You don't even know that you are doing this but you do it quickly and instinctively.

Maybe more surprising, Freud's insight that our likes and dislikes are due to factors that we're not necessarily conscious of has a lot of empirical support--a lot of empirical support from research into social psychology, for example. So, here's one finding from social psychology. If somebody goes through a terrible initiation to get into a club, they'll like the club more. You might think they'd like it less because people do terrible things to them. But actually, hazing is illegal but a remarkably successful tool. The more you pay for something the more you like it and the more pain you go through to get something the more you like it. From the standpoint of politics for instance, if you want loyal people in a political campaign, do not pay them. If you pay them, they'll like you less. If they volunteer, they'll like you more. And we'll talk about why. There's different theories about why, but my point right now is simply that people don't necessarily know this but still they're subject to this.

Another example is some weird studies done in a discipline of social psychology known as terror management which involves subliminal death primes. The idea of subliminal death primes is this. You sign up for your human subjects requirement and then you--they put you in front of a computer screen and then they tell you, "Oh, just sit in front of the computer screen and then we'll ask you some questions." And then the questions come out and they're questions like, "How much do you love your country?" "What do you think of Asians?" "What do you think of Jews?" "What do you think of blacks?" "What do you think of vegetarians?" "What do you think of people's political views different from yours?"

Here's the gimmick. What you don't know is on that computer screen words are being flashed like that but they're being flashed so fast it looks like that--You don't see anything--words like "corpse," "dead," "dying." The flashing of these subliminal words, "subliminal" meaning – a fancy term meaning below the level of consciousness, you don't know you're seeing them – has dramatic effects on how you answer those questions. People exposed to death primes become more nationalistic, more patriotic, less forgiving of other people, less liking of other races and people from other countries. Again the claim--the explanation for why this is so is something which we'll get to in another class. The point now is simply to illustrate that these sort of things can have--that things you aren't aware of can have an effect on how you think.

Introduction to Psychology: Lecture 2 Transcript

January 22, 2007 << back

Professor Paul Bloom: We're going to begin the class proper, Introduction to Psychology, with a discussion about the brain. And, in particular, I want to lead off the class with an idea that the Nobel Prize winning biologist, Francis Crick, described as "The Astonishing Hypothesis." And The Astonishing Hypothesis is summarized like this. As he writes, The Astonishing Hypothesis is that:

You, your joys and your sorrows, your memories and your ambitions, your sense of personal identity and free will are in fact no more than the behavior of a vast assembly of nerve cells and their associated molecules. As Lewis Carroll's Alice might have phrased it, "you're nothing but a pack of neurons."

It is fair to describe this as astonishing. It is an odd and unnatural view and I don't actually expect people to believe it at first. It's an open question whether you'll believe it when this class comes to an end, but I'd be surprised if many of you believe it now. Most people don't. Most people, in fact, hold a different view. Most people are dualists. Now, dualism is a very different doctrine. It's a doctrine that can be found in every religion and in most philosophical systems throughout history. It was very explicit in Plato, for instance.

But the most articulate and well-known defender of dualism is the philosopher Rene Descartes, and Rene Descartes explicitly asked a question, "Are humans merely physical machines, merely physical things?" And he answered, "no." He agreed that animals are machines. In fact, he called them "beast machines" and said animals, nonhuman animals are merely robots, but people are different. There's a duality of people. Like animals, we possess physical material bodies, but unlike animals, what we are is not physical. We are immaterial souls that possess physical bodies, that have physical bodies, that reside in physical bodies, that connect to physical bodies. So, this is known as dualism because the claim is, for humans at least, there are two separate things; there's our material bodies and there's our immaterial minds.

Now, Descartes made two arguments for dualism. One argument involved observations of a human action. So, Descartes lived in a fairly sophisticated time, and his time did have robots. These were not electrical robots, of course. They were robots powered by hydraulics. So, Descartes would walk around the French Royal Gardens and the French Royal Gardens were set up like a seventeenth-century Disneyland. They had these characters that would operate according to water flow and so if you stepped on a certain panel, a swordsman would jump out with a sword. If you stepped somewhere else, a bathing beauty would cover herself up behind some bushes. And Descartes said, "Boy, these machines respond in certain ways to certain actions so machines can do certain things and, in fact," he says, "our bodies work that way too. If you tap somebody on the knee, your leg will jump out. Well, maybe that's what we are." But Descartes said that can't be because there are things that humans do that no machine could ever do. Humans are not limited to reflexive action. Rather, humans are capable of coordinated, creative, spontaneous things. We can use language, for instance, and sometimes my use of language can be reflexive. Somebody says, "How are you?" And I say, "I am fine. How are you?" But sometimes I could say what I choose to be, "How are you?" "Pretty damn good." I can just choose. And machines, Descartes argued, are incapable of that sort of choice. Hence, we are not mere machines.

The second argument is, of course, quite famous and this was the method. This he came to using the method of doubt. So, he started asking himself the question, "What can I be sure of?" And he said, "Well, I believe there's a God, but honestly, I can't be sure there's a God. I believe I live in a rich country but maybe I've been fooled." He even said, "I believe I have had friends and family but maybe I am being tricked. Maybe an evil demon, for instance, has tricked me, has deluded me into thinking I have experiences that aren't real." And, of course, the modern version of this is The Matrix.

The idea of The Matrix is explicitly built upon Cartesian--Descartes' worries about an evil demon. Maybe everything you're now experiencing is not real, but rather is the product of some other, perhaps malevolent, creature. Descartes, similarly, could doubt he has a body. In fact, he noticed that madmen sometimes believe they have extra limbs or they believe they're of different sizes and shapes than they really are and Descartes said, "How do I know I'm not crazy? Crazy people don't think they're crazy so the fact that I don't think I'm crazy doesn't mean I'm not crazy. How do I know," Descartes said, "I'm not dreaming right now?" But there is one thing, Descartes concluded, that he cannot doubt, and the answer is he cannot doubt that he is himself thinking. That would be self-refuting. And so, Descartes used the method of doubt to say there's something really different about having a body that's always uncertain from having a mind. And he used this argument as a way to support dualism, as a way to support the idea that bodies and minds are separate. And so he concluded, "I knew that I was a substance, the whole essence or nature of which is to think, and that for its existence, there is no need of any place nor does it depend on any material thing. That is to say, the soul by which I am, when I am, is entirely distinct from body."

Now, I said before that this is common sense and I want to illustrate the common sense nature of this in a few ways. One thing is our dualism is enmeshed in our language. So, we have a certain mode of talking about things that we own or things that are close to us – my arm, my heart, my child, my car – but we also extend that to my body and my brain. We talk about owning our brains as if we're somehow separate from them. Our dualism shows up in intuitions about personal identity. And what this means is that common sense tells us that somebody can be the same person even if their body undergoes radical and profound changes. The best examples of this are fictional. So, we have no problem understanding a movie where somebody goes to sleep as a teenager and wakes up as Jennifer Garner, as an older person. Now, nobody says, "Oh, that's a documentary. I believe that thoroughly true" but at the same time nobody, no adult, no teenager, no child ever leaves and says, "I'm totally conceptually confused." Rather, we follow the story. We can also follow stories which involve more profound transformations as when a man dies and is reborn into the body of a child.

Now, you might have different views around--People around this room will have different views as to whether reincarnation really exists, but we can imagine it. We could imagine a person dying and then reemerging in another body. This is not Hollywood invention. One of the great short stories of the last century begins with a sentence by Franz Kafka: "As Gregor Samsa woke one morning from uneasy dreams, he found himself transformed in his bed into a gigantic insect." And again, Kafka invites us to imagine waking up into a body of a cockroach and we can. This is also not modern. Hundreds of years before the birth of Christ, Homer described the fate of the companions of Odysseus who were transformed by a witch into pigs. Actually, that's not quite right. She didn't turn them into pigs. She did something worse. She stuck them in the bodies of pigs. They had the head and voice and bristles and body of swine but their minds remained unchanged as before, so they were penned there weeping. And we are invited to imagine the fate of again finding ourselves in the bodies of other creatures and, if you can imagine this, this is because you are imagining what you are as separate from the body that you reside in.

We allow for the notion that many people can occupy one body. This is a mainstay of some slapstick humor including the classic movie, All of Me--Steve Martin and Lily Tomlin – highly recommended. But many people think this sort of thing really happens. One analysis of multiple personality disorder is that you have many people inside a single body fighting it out for control. Now, we will discuss multiple personality disorder towards the end of the semester and it turns out things are a good deal more complicated than this, but still my point isn't about how it really is but how we think about it. Common sense tells us you could have more than one person inside a single body. This shows up in a different context involving exorcisms where many belief systems allow for the idea that people's behavior, particularly their evil or irrational behavior, could be because something else has taken over their bodies.

Finally, most people around the world, all religions and most people in most countries at most times, believe that people can survive the destruction of their bodies. Now, cultures differ according to the fate of the body. Some cultures have the body going to--sorry--the fate of the soul. Some cultures have you going to Heaven or descending to Hell. Others have you occupying another body. Still, others have you occupying an amorphous spirit world. But what they share is the idea that what you are is separable from this physical thing you carry around. And the physical thing that you carry around can be destroyed while you live on.

These views are particularly common in the United States. In one survey done in Chicago a few years ago, people were asked their religion and then were asked what would happen to them when they died. Most people in the sample were Christian and about 96% of Christians said, "When I die I'm going to go to Heaven." Some of the sample was Jewish. Now, Judaism is actually a religion with a less than clear story about the afterlife. Still, most of the subjects who identified themselves as Jewish said when they die they will go to Heaven. Some of the sampled denied having any religion at all--said they have no religion at all. Still, when these people were asked what would happen when they would die, most of them answered, "I'm going to go to Heaven."

So, dualism is emmeshed. A lot rests on it but, as Crick points out; the scientific consensus now is that dualism is wrong. There is no "you" separable or separate from your body. In particular, there is no "you" separable from your brain. To put it the way cognitive scientists and psychologists and neuroscientists like to put it, "the mind is what the brain does." The mind reflects the workings of the brain just like computation reflects the working of a computer. Now, why would you hold such an outrageous view? Why would you reject dualism in favor of this alternative? Well, a few reasons. One reason is dualism has always had its problems. For one thing, it's a profoundly unscientific doctrine. We want to know as curious people how children learn language, what we find attractive or unattractive, and what's the basis for mental illness. And dualism simply says, "it's all nonphysical, it's part of the ether," and hence fails to explain it.

More specifically, dualists like Descartes struggle to explain how a physical body connects to an immaterial soul. What's the conduit? How could this connection be made? After all, Descartes knew full well that there is such a connection. Your body obeys your commands. If you bang your toe or stub your toe you feel pain. If you drink alcohol it affects your reasoning, but he could only wave his hands as to how this physical thing in the world could connect to an immaterial mind.

Descartes, when he was alive, was reasonable enough concluding that physical objects cannot do certain things. He was reasonable enough in concluding, for instance, as he did, that there's no way a merely physical object could ever play a game of chess because--and that such a capacity is beyond the capacity of the physical world and hence you have to apply--you have to extend the explanation to an immaterial soul but now we know--we have what scientists call an existence proof. We know physical objects can do complicated and interesting things. We know, for instance, machines can play chess. We know machines can manipulate symbols. We know machines have limited capacities to engage in mathematical and logical reasoning, to recognize things, to do various forms of computations, and this makes it at least possible that we are such machines. So you can no longer say, "Look. Physical things just can't do that" because we know physical things can do a lot and this opens up the possibility that humans are physical things, in particular, that humans are brains.

Finally, there is strong evidence that the brain is involved in mental life. Somebody who hold a--held a dualist view that said that what we do and what we decide and what we think and what we want are all have nothing to do with the physical world, would be embarrassed by the fact that the brain seems to correspond in intricate and elaborate ways to our mental life. Now, this has been known for a long time. Philosophers and psychologists knew for a long time that getting smacked in the head could change your mental faculties; that diseases like syphilis could make you deranged; that chemicals like caffeine and alcohol can affect how you think. But what's new is we can now in different ways see the direct effects of mental life.

Somebody with a severe and profound loss of mental faculties--the deficit will be shown correspondingly in her brain. Studies using imaging techniques like CAT scans, PET, and fMRI, illustrate that different parts of the brain are active during different parts of mental life. For instance, the difference between seeing words, hearing words, reading words and generating words can correspond to different aspects of what part of your brain is active. To some extent, if we put you in an fMRI scanner and observed what you're doing in real time, by looking at the activity patterns in your brain we can tell whether you are thinking about music or thinking about sex. To some extent we can tell whether you're solving a moral dilemma versus something else. And this is no surprise if what we are is the workings of our physical brains, but it is extremely difficult to explain if one is a dualist.

Now, so what you have is--the scientific consensus is that all of mental life including consciousness and emotions and choice and morality are the products of brain activities. So, you would expect that when you rip open the skull and look at the brain; you'd see something glorious, you'd see – I don't know – a big, shiny thing with glass tubes and blinding lights and sparks and wonderful colors. And actually though, the brain is just disgusting. It looks like an old meat loaf. It's gray when you take it out of the head. It's called gray matter but that's just because it's out of the head. Inside the head it's bright red because it's pulsing with blood. It doesn't even taste good. Well, has anybody here ever eaten brain? It's good with cream sauce but everything's good with cream sauce.

So, the question is, "How can something like this give rise to us?" And you have to have some sympathy for Descartes. There's another argument Descartes could have made that's a lot less subtle than the ones he did make, which is "That thing responsible for free will and love and consciousness? Ridiculous." What I want to do, and what the goal of neuroscience is, is to make it less ridiculous, to try to explain how the brain works, how the brain can give rise to thought, and what I want to do today is take a first stab at this question but it's something we'll continue to discuss throughout the course as we talk about different aspects of mental life. What I want to do though now is provide a big picture. So, what I want to do is start off small, with the smallest interesting part of the brain and then get bigger and bigger and bigger – talk about how the small part of the brain, the neurons, the basic building blocks of thought, combine to other mental structures and into different subparts of the brain and finally to the whole thing.

So, one of the discoveries of psychology is that the basic unit of the brain appears to be the neuron. The neuron is a specific sort of cell and the neuron has three major parts, as you could see illustrated here [pointing to the slide]. Neurons actually look quite different from one another but this is a typical one. There are the dendrites – these little tentacles here. And the dendrites get signals from other neurons. Now, these signals can be either excitatory, which is that they raise the likelihood the neuron will fire, or inhibitory in that they lower the likelihood that the neuron will fire. The cell body sums it up and you could view it arithmetically. The excitatory signals are pluses, the inhibitory ones are minuses. And then if you get a certain number, plus 60 or something, the neuron will fire and it fires along the axon, the thing to the right. The axon is much longer than the dendrites and, in fact, some axons are many feet long. There's an axon leading from your spinal cord to your big toe for instance. [the classroom lights accidentally go off] It is so shocking the lights go out.

Surrounded--Surrounding--To complete a mechanical metaphor that would have led Descartes to despair--[the classroom lights turn on] Thank you, Koleen. Surrounding the axon is a myelin sheath, which is actually just insulation. It helps the firing work quicker. So, here are some facts about neurons. There are a lot of them – about one thousand billion of them – and each neuron can be connected to around thousands, perhaps tens of thousands, other neurons. So, it's an extraordinarily complicated computing device. Neurons come in three flavors. There are sensory neurons, which take information from the world so as you see me, for instance, there are neurons firing from your retina sending signals to your brain. There are motor neurons. If you decide to raise your hand, those are motor neurons telling the muscles what to do. And there are interneurons which connect the two. And basically, the interneurons do the thinking. They make the connection between sensation and action.

It used to be believed, and it's the sort of thing I would--when I taught this course many years ago I would lecture on--that neurons do not grow back once you lose them. You never get them back. This is actually not true. There are parts of the brain in which neurons can re-grow.

One interesting thing about neurons is a neuron is like a gun. It either fires or it doesn't. It's all or nothing. If you squeeze the trigger of a gun really hard and really fast, it doesn't fire any faster or harder than if you just squeezed it gently. Now, this seems to be strange. Why? How could neurons be all or nothing when sensation is very graded? If somebody next to you pushed on your hand--the degree of pushing--you'd be able to notice it. It's not either pushing or not pushing. You can--Degrees of pushing, degrees of heat, degrees of brightness. And the answer is, although neurons are all or nothing, there are ways to code intensity. So, one simple way to code intensity is the number of neurons firing; the more neurons the more intense. Another way to increase intensity is the frequency of firing. So, I'll just use those two. The first one is the number of neurons firing. The second one is the frequency of firing in that something is more intense if it's "bang, bang, bang, bang, bang, bang" then [louder] "bang, bang, bang" and these are two ways through which neurons encode intensity.

Now, neurons are connected and they talk to one another and it used to be thought they were tied to one another like a computer, like you take wires and you connect wires to each other, you wrap them around and connect them. It turns out this isn't the case. It turns out that neurons relate to one another chemically in a kind of interesting way. Between any neurons, between the axon of one neuron and the dendrite of another, there's a tiny gap. The gap could be about one ten-thousandths of a millimeter wide. This infinitesimal gap--and this gap is known as a synapse--and what happens is when a neuron fires, an axon sends chemicals shooting through the gap. These chemicals are known as neurotransmitters and they affect the dendrites. So, neurons communicate to one another chemically. These--Again, the chemicals could excite the other neuron (excitatory) bring up the chances it will fire, or inhibit the other neuron (inhibitory).

Now, neurotransmitters become interesting because a lot of psychopharmacology, both of the medical sort and the recreational sort, consists of fiddling with neurotransmitters and so you could see this through some examples. There are two sorts of ways you could fiddle with neurotransmitters, and correspondingly two sorts of drugs. There are agonists. And what an agonist does is increases the effect of neurotransmitters, either by making more neurotransmitters or stopping the cleanup of neurotransmitters, or in some cases by faking a neurotransmitter, by mimicking its effects. Then, there are antagonists that slow down the amount of neurotransmitters, either because they destroy neurotransmitters or they make it hard to create more. Or in some cases they go to the dendrite of the neuron and they kind of put a paste over it so that the neurotransmitters can't connect. And it's through these clever ways that neurons can affect your mental life.

So, for instance, there is a drug known as Curare and Curare is an antagonist. It's a very particular sort of antagonist. It blocks motor neurons from affecting muscle fibers. What this does then is it paralyzes you because your motor neurons--You send the command to your arm to stand, to lift up. It doesn't work. You send the command to your leg to move. It doesn't work. The motor neurons are deactivated and then, because the way you breathe is through motor neurons, you then die.

There's alcohol. Alcohol is inhibitory. Now, this may be puzzling to people. It's mildly paradoxical because you may be thinking, "alcohol is not inhibitory. On the contrary, when I drink a lot of alcohol I lose my inhibitions and become a more fun person. I become more aggressive and more sexually vibrant and simply more beautiful. And so in what way is alcohol inhibitory?" Well, the answer is it inhibits the inhibitory parts of your brain. So, you have parts of your brain that are basically telling you now, largely in the frontal lobes, that are--"Okay. Keep your pants on. Don't hit me, buddy. Don't use bad words." Alcohol relaxes, shuts down those parts of the brain. If you take enough alcohol, it then goes down to inhibit the excitatory parts of your brain and then you fall on the floor and pass out.

Amphetamines increase the amount of arousal. In particular, they increase the amount of norepinephrine, a neurotransmitter that's responsible for just general arousal. And so, amphetamines include drugs like "speed" and "coke." There are--Prozac works on serotonin. When we discuss clinical psychology and depression we'll learn the extent to which neurotransmitter disorders are implicated in certain disorders like depression. And one problem is that – for depression – is that there's too little of a neurotransmitter known as serotonin. Prozac makes serotonin more prevalent and so in some extent might help alleviate depression. Parkinson's disease is a disease involving destruction of motor control and loss of motor control, difficulty moving. And one factor in Parkinson's is too little of a neurotransmitter known as dopamine. The drug L-DOPA increases the supply of dopamine and so there is something to alleviate, at least temporarily, the symptoms of Parkinson's.

So, you have neurons and they're clustered together and they fire and they communicate to one another. So, how does this all work to give rise to creatures who could do interesting things like talk and think? Well, again, it used to be believed that the brain is wired up like a computer, like a PC or a Mac or something like that, but we know this can't be true. It can't be true because there's two ways in which the brain is better than a computer. For one thing, the brain is highly resistant to damage. If you have a laptop and I persuade you to open it up for me and I take the pliers and kind of snip just about anywhere, your laptop will be destroyed but the brain is actually more resilient. You can take a lot of brain damage and still preserve some mental functioning. To some interesting sense, there's some sort of damage resistance built in to the brain that allows different parts of the brain to take over if some parts are damaged.

A second consideration is the brain is extremely fast. Your computer works on wires and electricity but your brain uses tissue and tissue is extremely slow. The paradox then is how do you create such a fast computer with such slow stuff? And you can't. If the brain was wired up like a personal computer, it would take you four hours to recognize a face but, in fact, we could do things extremely quickly. So, the question then is how is the brain wired up? And the answer is, unlike manys, unlike commercially generated computers, the brain works through parallel processing, massively parallel distributed processing.

There's a whole lot of research and this is research, some of which takes place outside psychology departments and in engineering departments and computer science departments, trying to figure out how a computer can do the same things brains can do. And one way people do this is they take a hint from nature and they try to construct massively distributed networks to do aspects of reasoning. So, there's a very simple computational network. That is interesting because it kind of looks to some extent like the way neurons look and this is often known as neural networks. And people who study this often claim to be studying neural network modeling to try to build smart machines by modeling them after brains. And in the last 20 years or so, this has been a huge and vibrant area of study where people are trying to wire up machines that can do brain-like things from components that look a lot like neurons and are wired up together as neurons are. One consideration in all of this is that this is a very young field and nobody knows how to do it yet. There is no machine yet that can recognize faces or understand sentences at the level of a two-year-old human. There is no machine yet that can do just about anything people can do in an interesting way. And this is, in part, because the human brain is wired up in an extraordinarily more complicated way than any sort of simple neural network. This is a sort of schematic diagram – you're not responsible for this – of parts of the visual cortex, and the thing to realize about this is it's extraordinarily simplified. So, the brain is a complicated system.

Now, so, we've talked a little bit about the basic building blocks of the brain – neurons. We've then talked about how neurons can communicate to one another; then, [we] turned to how neurons are wired up together. Now let's talk a little bit about different parts of the brain. Now, there's some things you don't actually need your brain to do. The study of what you don't need your brain to do has often drawn upon this weird methodology where--This was actually done in France a lot where they would decapitate people and when--After they decapitated people, psychologists would rush to the body of the headless person and sort of just test out reflexes and stuff like that. It's kind of gruesome but we know there are some things you don't need your brain for.

You don't need your brain for newborn sucking, limb flexation in withdrawal from pain. Your limbs will pull back even if your head is gone. Erection of the penis can be done without a brain. Vomiting also is done without a brain. Oh. I need a volunteer. Very simple. This will not involve any of--excellent--any of the above. Could you stand up just--Okay. This is a new shirt so I want to stay away. Just--No. This is--If you'll hold out your hand and--one hand flat. [The student holds his hand out flat] Excellent. [Professor Paul Bloom raises a book above the student's hand] That's the textbook, 5th edition. Now. [Professor Paul Bloom drops the book onto the student's hand. After succumbing to the weight of the book the student's hand automatically raises back up] Perfect. What you'll notice is--Thank you very much. What you'll notice is this hit and this hand went back up. This is something automatic, instinctive, and does not require your brain. So your brain isn't needed for everything.

What does your brain do? Well, some things that your brain does involve very low-level internal structures. And these are called subcortical structures because they're below the cortex. They're underneath the cortex. So, for instance, what we have here [gesturing toward the slides] is a diagram of the brain. The way to read this diagram is it's as if it were my brain and I am facing this way. My head gets cut in half down here and then you could see the brain. So, this is the front over here. That's the back. Some key parts are illustrated here. The medulla, for instance, is responsible for heart rate and respiration. It's very deep within the brain and if it gets damaged you could--you are likely to die. The cerebellum is responsible for body balance and muscular coordination. And to give you, again, a feeling for the complexity of these systems, the cerebellum contains approximately 30 billion neurons. The hypothalamus is responsible here for feeding, hunger, thirst, and to some extent sleep. And here is the same brain parts in close-up.

Now, all of these parts of the brains are essential and many of them are implicated in interesting psychological processes but where the action is is the cortex. Isn't this beautiful? The cortex is the outer layer and the outer layer is all crumpled up. Do you ever wonder why your brain looks wrinkled? That's because it's all crumpled. If you took out somebody's cortex and flattened it out, it would be two feet square, sort of like a nice--like a rug. And the cortex is where all the neat stuff takes place. Fish don't have any of that, so no offense to fish but it's--fish don't have much of a mental life. Reptiles and birds have a little bit about it--of it--and primates have a lot and humans have a real lot. Eighty percent of the volume of our brain, about, is cortex. And the cortex can be broken up into different parts or lobes. There is the--And, again, this is facing in profile forward. There is the frontal lobe, easy to remember. This part in front, the parietal lobe, the occipital lobe, and the temporal lobe.

And one theme we're going to return to is--this is half the brain. This is, in fact, the left half of the brain. On the other half, the right half, everything's duplicated with some slight and subtle differences. What's really weird--One really weird finding about these lobes is that they include topological maps. They include maps of your body. There is a cartoon which actually illustrates a classic experiment by some physiologists who for some reason had a dog's brain opened up and started shocking different parts of the brain. You could do brain surgery while fully conscious because the brain itself has no sense organs to it. And it turns out that the dog--When they zapped part of its brain, its leg would kick up.

And it took Dr. Penfield at McGill University to do the same thing with people. So, they were doing some brain surgery. He had a little electrical thing just on--I don't know how he thought to do this. He started zapping it and "boom." The person--Parts of their body would move. More than that, when he zapped other parts of the brain, people would claim to see colors. And he zapped other parts of the brain; people would claim to hear sounds; and other parts of the brain, people would claim to experience touch. And through his research and other research, it was found that there are maps in the brain of the body. There is a map in the motor part of the brain, the motor cortex, of the sort up on the left and the sensory cortex of the sort that you could see on the right and if you--and you could tell what's what by opening up the brain and shocking different parts and those parts would correspond to the parts of the body shown in the diagram there.

Now, two things to notice about these maps. The first is they're topographical and what this means is that if two parts of the--two parts are close together on the body, they'll be close together on the brain. So, your tongue is closer to your jaw than it is to your hip in the body; so too in both the motor cortex and the somatosensory cortex. Also, you'll notice that the size of the body part represented in the brain does not correspond to the size of the body part in the real world. Rather, what determines the size in the brain is the extent to which either they have motor command over it or sensory control. So, there's a whole lot of sensory organs, for instance, focused along your tongue, and that's why that's so big, and an enormous amount on your face but your shoulder isn't even--doesn't even make it on there because, although your shoulder might be bigger than your tongue, there's not much going on. In fact, if you draw a diagram of a person, what their body is corresponding to the amount of somatosensory cortex, you get something like that [gesturing toward the slide]. That's your sensory body.

Now, so, you have these maps in your head but the thing to realize is--And these maps are part of your cortex, but the things to realize is that's an important part of what goes on in your brain but less than one quarter of the cortex contains these maps or projection areas. The rest is involved in language and reasoning and moral thought and so on. And, in fact, the proportion as you go from rat, cat, and monkey, humans--less and less of it is devoted to projection and there is more and more to other things. So, how do we figure out what the other parts of the brain do? Well, there's all sorts of methods. Typically, these are recent imaging methods like CAT scan and PET scan and fMRI which, as I said before, show parts of your brain at work. If you want to know which part of your brain is responsible for language, you could put somebody into a scanner and have them exposed to language or do a linguistic task or talk or something and then see what parts of their brain are active.

Another way to explore what the brain does is to consider what happens to people when very bad things happen to their brain. And these bad things could happen through lesions, through tumors, through strokes, through injury. For the most part, neuropsychologists don't like helmet laws. Neuropsychologists love when motorcyclists drive without helmets because through their horrible accidents we gain great insights into how the brain works. And the logic is if you find somebody--Crudely, if you find somebody with damage to this part of the brain right here and that person can't recognize faces for instance, there's some reason to believe that this part of the brain is related to face recognition.

And so, from the study of brain damage and the study of--we can gain some understanding of what different parts of the brain do. And so, people study brain damages--brain damage that implicates motor control such as apraxia. And what's interesting about apraxia is it's not paralysis. Somebody with apraxia can move, do simple movements just fine but they can't coordinate their movements. They can't do something like wave goodbye or light a cigarette.

There is agnosia and agnosia is a disorder which isn't blindness because the person could still see perfectly well. Their eyes are intact but rather what happens in agnosia is they lose the ability to recognize certain things. Sometimes this is described as psychic blindness. And so, they may get visual agnosia and lose the ability to recognize objects. They may get prosopagnosia and lose the ability to recognize faces. There are disorders of sensory neglect, some famous disorders. Again, it's not paralysis, it's not blindness, but due to certain parts of your--of damaged parts of your brain, you might lose, for instance, the idea that there's a left side of your body or a left side of the world. And these cases are so interesting I want to devote some chunk to a class in the next few weeks to discussing them.

There are disorders of language like aphasia. The classic case was discovered by Paul Broca in 1861. A patient who had damage to part of his brain and can only say one word, "tan," and the person would say, "tan, tan, tan, tan," and everything else was gone. There's other disorders of language such as receptive aphasia where the person could speak very fluently but the words don't make any sense and they can't understand anybody else. Other disorders that we'll discuss later on include acquired psychopathy, where damage to parts of your brain, particularly related to the frontal lobes, rob you of the ability to tell right from wrong.

The final--I want to end--We're talking about neurons, connection between neurons, how neurons are wired up, the parts of the brain, what the different parts do. I want to end by talking about the two halves of the brain and ask the question, "How many minds do you have?" Now, if you look at the brain--If you took the brain out and held it up, it would look pretty symmetrical, but it actually is not. There are actual differences between the right hemisphere and the left hemisphere. How many people here are right-handed? How many people here are left-handed? How many people here are sort of complicated, ambidextrous, don't know, "bit of the right, bit of left" people? Okay. Those of you who are right-handed, which comprises about nine out of ten people, have language in your left hemisphere. And, in fact, we're going to be talking about right-handed people for the most part, making generalizations in what I'll talk about now. Those of you who are left-handed are more complicated. Some of you have language in your right hemisphere, some in your left hemisphere, some God knows where. It's complicated.

Now, the idea is that some things are duplicated. So, if you were to lose half your brain, the other half can actually do a lot but some things are more prevalent and more powerful in one part of the brain than the other. And I want to show you a brief film clip from "Scientific American" that illustrates the differences between the hemispheres, but before doing that, I want to provide some introductory facts. Some functions are lateralized. So, typically, language in the left. Again, this is a right-handed centric thing but if you're right-handed – language on the left, math and music on the right. There is a crossover and this is important when we think about the studies that will follow but the crossover is that everything you see in the left visual field goes to the right side of your brain; everything in the right visual field goes to the left side of the brain, and similarly, there's a crossover in action. So, your right hemisphere controls the left side of the body. Your left hemisphere controls the right side of the body. Now, finally, the two halves are connected. They're connected by this huge web called the corpus callosum. And I'm just going to skip this because the movie illustration will go through some of this.

This is an excellent summary of a discussion of Michael Gazzaniga, who's one of the world's top neuroscientists and the leading expert on the two halves of the brain. The only flaw in this movie is people are just extremely pleased with themselves, so you have to ignore that while watching it. Is that working? Do you people hear it?

[Professor Bloom plays a short video clip]

Now, I'll end on that happy note. This illustrates certain themes that are discussed in detail in the Gray book, concerning the lateralization of different parts of different mental capacities, some in the left hemisphere, some in the right hemisphere. But it also serves as a useful methodological development, which is a nice illustration as to how looking at people who are incredibly unusual, such as this man who had his brain bisected so his left hemisphere and his right hemisphere don't communicate with one another--how looking at such people, such extreme cases, can provide us with some understanding of how we normally do things. And this, again, is a theme we'll return to throughout the course.

This is generally the general introduction of the brain that I wanted to provide, giving the framework for what I'll be talking about later on throughout the course so that I might later on make reference to neurons or neurotransmitters or the cortex or the left hemisphere and you'll sort of have the background to understand what I'm talking about. But I want to end this first real class with a bit of humility as to what psychologists know and don't know. So, the idea behind a lot of psychology – particularly a lot of neuroscience and cognitive psychology – is to treat the mind as an information processor, as an elaborate computer. And so, we study different problems like recognizing faces or language or motor control or logic. The strategy then often is to figure out how, what sort of program can solve these problems and then we go on to ask, "How could this program be instantiated in the physical brain?" So, we would solve--We study people much as we'd study a computer from an alien planet or something. And I think--This strategy is one I'm very enthusiastic about but there still remains what's sometimes called the "hard problem" of consciousness and this involves subjective experience. What's it like? So, my computer can play chess. My computer can recognize numbers. It can do math. And maybe it does it kind of the same way that I do it but my computer doesn't have feelings in the same sense.

These are two classic illustrations. This [pointing at a picture on the slide] is from a very old "Star Trek" episode. It illustrates angst. I think a starship's about to go into the sun or something. And that's [pointing at a another picture on the slide] my older kid, Max, who's happy. And so the question is, "How does a thing like that give rise to consciousness and subjective experience?" And this is a deep puzzle. And although some psychologists and philosophers think they've solved it, most of us are a lot more skeptical. Most of us think we have so far to go before we can answer questions like Huxley's question. Huxley points out, "How it is that anything so remarkable as a state of consciousness comes about as a result of irritating nervous tissue, is just as unaccountable as the appearance of the Djinn…" – of the genie – "…when Aladdin rubs his lamp." It seems like magic that a fleshy lump of gray, disgusting meat can give rise to these feelings.

The second bit of humility we'll end the class on is I am presenting here, and I'll be presenting throughout this semester, what you can call a mechanistic conception of mental life. I'm not going to be talking about how beautiful it is and how wonderful it is and how mysterious it is. Rather, I'm going to be trying to explain it. I'm going to be trying to explain fundamental aspects of ourselves including questions like how do we make decisions, why do we love our children, what happens when we fall in love, and so on.

Now, you might find this sort of project in the end to be repellant. You might worry about how this, well, this meshes with humanist values. For instance, when we deal with one another in a legal and a moral setting, we think in terms of free will and responsibility. If we're driving and you cut me off, you chose to do that. It reflects badly on you. If you save a life at risk to your own, you're--you deserve praise. You did something wonderful. It might be hard to mesh this with the conception in which all actions are the result of neurochemical physical processes. It might also be hard to mesh a notion such as the purported intrinsic value of people. And finally, it might be hard to mesh the mechanistic notion of the mind with the idea that people have spiritual value.

Faced with this tension, there are three possibilities. You might choose to reject the scientific conception of the mind. Many people do. You may choose to embrace dualism, reject the idea that the brain is responsible for mental life, and reject the promise of a scientific psychology. Alternatively, you might choose to embrace the scientific worldview and reject all these humanist values. And there are some philosophers and psychologists who do just that, who claim that free will and responsibility and spiritual value and intrinsic value are all illusions; they're pre-scientific notions that get washed away in modern science or you could try to reconcile them. You could try to figure out how to mesh your scientific view of the mind with these humanist values you might want to preserve. And this is an issue which we're going to return to throughout the course. Okay. I'll see you on Wednesday.