Professor Paul Bloom: I actually want to begin by going backto Freud and hitting a couple of loose ends. There was a point in mylecture on Wednesday where I skipped over some parts. I said, "We don'thave time for this" and I just whipped past it. And I couldn't sleepover the weekend. I've been tormented. I shouldn't have skipped thatand I want to hit--Let me tell you why I skipped it. The discussion Iskipped was the discussion of why we would have an unconscious at all.So, I was talking about the scientifically respectable ideas of Freudand I want to talk about some new ideas about why there could be anunconscious.心理学空间*mzB9UlFF
Now, the reason why I skipped it is I'm not sure this is the bestway to look at the question. As we will learn throughout the course, byfar the vast majority of what our brains do, the vast majority of whatour minds do, is unconscious and we're unaware of it. So the rightquestion to ask may not be, "Why are some things unconscious?" butrather, why is this tiny subset of mental life--why is this conscious?On the other hand, these claims about the utility of unconsciousness, Ithink, are provocative and interesting. So I just wanted to quicklyshare them with you.
So, the question is, from an evolutionary standpoint, "Why would anunconscious evolve?" And an answer that some psychologists andbiologists have given is deception. So, most animals do some deception.And deception defined broadly is simply to act or be in some way thatfools others into believing or thinking or responding to somethingthat's false.心理学空间o6crBZl5M
There's physical examples of deception. When threatened,chimpanzees--their hair stands up on end and that makes them lookbigger 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 rodsticking 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 tothemselves be devoured. But humans, primates in general butparticularly humans, are masters of deception. We use our minds and ourbehaviors and our actions continually to try to trick people intobelieving what's not true. We try to trick people, for instance, intobelieving that we're tougher, smarter, sexier, more reliable, moretrustworthy and so on, than we really are. And a large part of socialpsychology concerns the way in which we present ourselves to otherpeople so as to make the maximally positive impression even when thatimpression isn't true.心理学空间@\d3U0[9~s&w:u
At the same time, though, we've also evolved very good lie detectionmechanisms. So not only is there evolutionary pressure for me to lie toyou, for me to persuade you for instance, that if we're going to havea--if you are threatening me don't threaten me, I am not the sort ofman you could screw around with. But there's evolutionary pressure foryou to look and say, "No. You are the sort of man you could screwaround with. I can tell." So how do you become a good liar? And here'swhere the unconscious comes in. The hypothesis is: the best lies arelies we tell ourselves. You're a better liar, more generally, if youbelieve the lie that you're telling.
This could be illustrated with a story about Alfred Hitchcock. Thestory goes--He hated working with child actors but he often had to. Andthe story goes--He was dealing with a child actor who simply could notcry. And, finally frustrated, Hitchcock went to the actor, leaned over,whispered in his ear, "Your parents have left you and they're nevercoming back." The kid burst into tears. Hitchcock said, "Roll ‘em" andfilmed 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. IfI had a competition where I'd give $100,000 to the person who looks themost as if they are in pain, it is a very good tactic to take a pen andjam it into your groin because you will look extremely persuasively asif you are in pain. If I want to persuade you that I love you, wouldnever leave you, you can trust me with everything, it may be a superbtactic for me to believe it. And so, this account of the evolution ofthe unconscious is that certain motivations and goals, particularlysinister ones, are better made to be unconscious because if a persondoesn't know they have them they will not give them away. And this issomething I think we should return to later on when we talk aboutsocial interaction and social relationships.心理学空间(YT)H"[ m4k
/WY moF}r"xR9O0One other thing on Freud--just a story of the falsification ofFreud. I was taking my younger child home from a play date on Sundayand he asked me out of the blue, "Why can't you marry your mother oryour father?" Now, that's actually a difficult question to ask--toanswer for a child, but I tried my best to give him an answer. And thenI said--then I thought back on the Freud lecture and so I asked him,"If you could marry anybody you want, who would it be?" imagining he'dmake explicit the Oedipal complex and name his mother. Instead, hepaused for a moment and said, "I would marry a donkey and a big bag ofpeanuts." [laughter] Both his parents are psychologists and he hatesthese questions and at times he just screws around with us.[laughter]心理学空间P0y R)b1?HHme9}
b)E8Mg?q"Z0Okay. Last class I started with Freud and now I want to turn toSkinner. And the story of Skinner and science is somewhat differentfrom the story of Freud. Freud developed and championed the theory ofpsychoanalysis by himself. It is as close as you could find in scienceto a solitary invention. Obviously, he drew upon all sorts of sourcesand predecessors but psychoanalysis is identified as Freud's creation.Behaviorism is different. Behaviorism is a school of thought that wasthere long before Skinner, championed by psychologists like JohnWatson, for instance. Skinner came a bit late into this but the reasonwhy we've heard of Skinner and why Skinner is so well known is hepackaged these notions. He expanded upon them; he publicized them; hedeveloped them scientifically and presented them both to the scientificcommunity and to the popular community and sociologically in the 1960sand 1970s. In the United States, behaviorism was incredibly well knownand so was Skinner. He was the sort of person you would see on talkshows. His books were bestsellers.心理学空间 hN'bRa`
Now, at the core of behaviorism are three extremely radical andinteresting views. The first is a strong emphasis on learning. Thestrong 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 JohnWatson and in this quote John Watson is paraphrasing a famous boast bythe Jesuits. The Jesuits used to claim, "Give me a child until the ageof seven and I'll show you the man," that they would take a child andturn him into anything they wanted. And Watson expanded on thisboast,心理学空间h*V@'fQ R} ]B
Give me a dozen healthy infants, well-formed and my ownspecified world to bring them up and I'll guarantee to take any one atrandom and train them to become any type of specialist I mightselect--doctor, lawyer, artist, merchant, chief, and yes, evenbeggar-man and thief, regardless of his talents, penchants, tendencies,abilities, vocations and race of his ancestors.
Hl`*YI?`0Now, you could imagine--You could see in this a tremendous appeal tothis 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 ofhumans by dint of their race or their sex could be better than anothergroup. And Watson was explicit. None of those facts about people willever make any difference. What matters to what you are is what youlearn and how you're treated. And so, Watson claimed he could createanybody in any way simply by treating them in a certain fashion.
`~G m!u2j0A second aspect of behaviorism was anti-mentalism. And what I meanby this is the behaviorists were obsessed with the idea of doingscience and they felt, largely in reaction to Freud, that claims aboutinternal mental states like desires, wishes, goals, emotions and so on,are unscientific. These invisible, vague things can never form thebasis of a serious science. And so, the behaviorist manifesto wouldthen be to develop a science without anything that's unobservable andinstead use notions like stimulus and response and reinforcement andpunishment and environment that refer to real world and tangibleevents.心理学空间7PCX5Hf*pW+S)]9a0g(@%H
4tI&D L GG w0Finally, behaviorists believed there were no interesting differencesacross species. A behaviorist might admit that a human can do thingsthat a rat or pigeon couldn't but a behaviorist might just say, "Look.Those are just general associative powers that differ" or they may evendeny it. They might say, "Humans and rats aren't different at all. It'sjust humans tend to live in a richer environment than rats." From thatstandpoint, from that theoretical standpoint, comes a methodologicalapproach which is, if they're all the same then you could study humanlearning by studying nonhuman animals. And that's a lot of what theydid.
Okay. I'm going to frame my introduction--my discussion of behaviorsin terms of the three main learning principles that they argue canexplain all of human mental life, all of human behavior. And then, Iwant to turn to objections to behaviorism but these three principlesare powerful and very interesting.心理学空间!j Y PH(b:w
The first is habituation. This is the very simplest form oflearning. And what this is is technically described as a decline in thetendency to respond to stimuli that are familiar due to repeatedexposure. "Hey!" [shouting, then pausing] "Hey!" [shouting again] Thesudden noise startles but as it--as you hear it a second time itstartles less. The third time is just me being goofy. It'sjust--It's--You get used to things. And this, of course, is commonenough in everyday life. We get used to the ticking of a clock or tonoise of traffic but it's actually a very important form of learningbecause imagine life without it. Imagine life where you never got usedto anything, where suddenly somebody steps forward and waves their handand you'd go, "Woah," [as if surprised] and then they wave their handagain and you'd go, "Whoah," [as if surprised again] and youkeep--[laughter]
And there's the loud ticking of a clock and you say, "Hmmm." [actingas if he's interested in the sound of a clock ticking] And that's notthe way animals or humans work. You get used to things. And it'sactually critically important to get used to things because it's auseful adaptive mechanism to keep track on new events and objects. It'simportant to notice something when it's new because then you have todecide whether it's going to harm you, how to deal with it, to attendto it, but you can't keep on noticing it. And, in fact, you should stopnoticing it after it's been in the environment for long enough. So,this counts as learning because it happens through experience. It's away to learn through experience, to change your way of thinking throughexperience. And also, it's useful because harmful stimuli are noticedbut when something has shown itself to be part of the environment youdon't notice it anymore.
%N"O.iI?Mv5d0The existence of habituation is important for many reasons. Onething it's important for is clever developmental psychologists haveused habituation as a way to study people, creatures who can't talklike nonhuman animals, and young babies. And when I talk on Wednesdayabout developmental psychology I'll show different ways in whichpsychologists have used habituation to study the minds of youngbabies.心理学空间Z0\v j"I)c
The second sort of learning is known as classical conditioning. Andwhat this is in a very general sense is the learning of an associationbetween one stimulus and another stimulus, where stimulus is atechnical term meaning events in the environment like a certain smellor sound or sight. It was thought up by Pavlov. This is Pavlov's famousdog and it's an example of scientific serendipity. Pavlov, when hestarted this research, had no interest at all in learning. He wasinterested in saliva. And to get saliva he had to have dogs. And he hadto attach something to dogs so that their saliva would pour out so hecould study saliva. No idea why he wanted to study saliva, but he thendiscovered something. What he would do is he'd put food powder in thedog's mouth to generate saliva. But Pavlov observed that when somebodyentered the room who typically gave him the food powder, the dog--thefood powder saliva would start to come out. And later on if you--rightbefore or right during you give the dog some food – you ping a bell –the bell will cause the saliva to come forth. And, in fact, this is theapparatus that he used for his research.
He developed the theory of classical conditioning by making adistinction between two sorts of conditioning, two sorts of stimulusresponse relationships. One is unconditioned. An unconditioned is whenan unconditioned stimulus gives rise to an unconditioned response. Andthis is what you start off with. So, if somebody pokes you with a stickand you say, "Ouch," because it hurts, the poking and the "ouch" is anunconditioned stimulus causing an unconditioned response. You didn'thave to learn that.心理学空间x8pR@9i#q
When Pavlov put food powder in the dog's mouth and saliva wasgenerated, that's an unconditioned stimulus giving rise to anunconditioned response. But what happens through learning is thatanother association develops – that between the conditioned stimulusand the conditioned response. So when Pavlov, for instance--Well, whenPavlov, for instance, started before conditioning there was simply anunconditioned stimulus, the food in the mouth, and an unconditionedresponse, saliva. The bell was nothing. The bell was a neutralstimulus. But over and over again, if you put the bell and the foodtogether, pretty soon the bell will generate saliva. And now thebell--When--You start off with the unconditioned stimulus,unconditioned response. When the conditioned stimulus and theunconditioned stimulus are brought together over and over and overagain, pretty soon the conditioned stimulus gives rise to the response.And now it's known as the conditioned stimulus giving rise to theconditioned response. This is discussed in detail in the textbook but Ialso--I'm going to give you--Don't panic if you don't get it quite now.I'm going to give you further and further examples.心理学空间A;Z H)w3jZZ%d
So, the idea here is, repeated pairings of the unconditionedstimulus and the conditioned stimulus will give rise to the response.And there's a difference between reinforced trials and unreinforcedtrials. A reinforced trial is when the conditioned stimulus and theunconditioned stimulus go together. You're--and to put it in a crudeway, you're teaching the dog that the bell goes with the food. Anunreinforced trial is when you get the food without the bell. You'renot teaching the dog this. And, in fact, once you teach an animalsomething, if you stop doing the teaching the response goes away andthis is known as extinction.心理学空间N8JI?rq A8X,O
E+Ra!I1~K9ZNT0But here's a graph. If you get--They really count the number ofcubic centimeters of saliva. The dog is trained so that when the bellcomes on--Actually, I misframed it. I'll try again. When the bell comesconnected with food, there's a lot of saliva. An unreinforced responseis when the bell goes on but there's no food. So, it's--Imagine you'rethe dog. So, you get food in your mouth, "bell, food, [making pantingsound] bell, food, [another panting sound]" and now "bell [panting]."But next you get "bell, bell, bell." You give it up. You stop. You stopresponding to the bell. A weird thing which is discussed in thetextbook is if you wait a while and then you try it again with the bellafter a couple of hours, the saliva comes back. This is known asspontaneous recovery.心理学空间ur.M"RZ R/wz)[
So, this all seems a very technical phenomena related to animals andthe like but it's easy to see how it generalizes and how it extends.One interesting notion is that of stimulus generalization. And stimulusgeneralization is the topic of one of your articles inThe NortonReader, the one by Watson, John Watson, the famous behaviorist, whoreported a bizarre experiment with a baby known as Little Albert. Andhere's the idea. Little Albert originally liked rats. In fact, I'mgoing to show you a movie of Little Albert originally liking rats. See.[pointing to video] He's okay. No problem. Now, Watson did somethinginteresting. As Little Albert was playing with the rat, "Oh, I likerats, oh," Watson went behind the baby--this is the--it's in thechapter--and banged the metal bar right here [simulating a bangingmotion]. The baby, "Aah," screamed, started to sob. Okay. What's theunconditioned stimulus? Somebody. The loud noise, the bar, the bang.What's the unconditioned response? Crying, sadness, misery. And as aresult of this, Little Albert grew afraid of the rat. So there--whatwould be the conditioned stimulus? The rat. What would be theconditioned response? Fear. Excellent.
PAmHV/? yg7N h0Moreover, this fear extended to other things. So, this is a veryweird and unpersuasive clip. But the idea is--the clip is to make thepoint that the fear will extend to a rabbit, a white rabbit. So, thefirst part, Little Albert's fine with the white rabbit. The second partis after he's been conditioned and he's kind of freaked out with thewhite rabbit. The problem is in the second part they're throwing therabbit at him but [looking at the video] now he's okay. [laughter]
[Speaking to a teaching assistant] Is the mic on? Oh. This isfine.心理学空间PsN~%Bl(~|!p
&h4Ux6S7|lU0This is one of a long list of experiments that we can't do anymore.So, classical conditioning is more than a laboratory phenomena. Thefindings of classical conditioning have been extended and replicated inall sorts of animals including crabs, fish, cockroaches and so on. Andit's been argued to be an extension of--it's argued to underlie certaininteresting aspects of human responses.
)e9O_PMY`0So, I have some examples here. One example is fear. So, the LittleAlbert idea--The Little Albert experiment, provides an illustration forhow phobias could emerge. Some proportion of people in this room havephobias. Imagine you're afraid of dogs. Well, a possible story forthe--for why you became afraid of dogs is that one day a dog came upand he was a neutral stimulus. No problem. And all of a sudden he bityou. Now the pain of a bite, being bit, and then the pain and fear ofthat is an unconditioned stimulus, unconditioned response. You're justborn with that, "ow." But the presence of the dog there is aconditioned stimulus and so you grew to be afraid of dogs.5f*iK,XP%U0
!G%s4W.[-xCyd0If you believe this, this also forms the basis for ways for a theoryof how you could make phobias go away. How do you make conditionedstimulus, conditioned response things go away? Well, what you do is youextinguish them. How do you extinguish them? Well, you show the thingthat would cause you to have the fear without the unconditionedstimulus. Here's an illustration. It's a joke. Sorry. [pointing towardsa slide containing a comic of a man trapped in a small booth, filledwith snakes, dangling from the top of a building] He's simultaneouslyconfronting the fear of heights, snakes, and the dark because he'strapped in that thing and the logic is--the logic of--the logic is notbad. He's stuck in there. Those are all the--his conditioned stimulus.But nothing bad happens so his fear goes away. The problem with this iswhile he's stuck in there he has this screaming, horrific panic attackand then it makes his fear much worse.