字幕列表 影片播放 列印英文字幕 >> John Boyd: All right. I'm John Boyd. It is my great pleasure to introduce Professor Kahneman today. And I just want to give you a brief background on his outstanding career. He started in 1954 received his bachelors in experimental psychology and mathematics from the Hebrew University in Jerusalem. In 1961, he was awarded his Ph.D. from University of California Berkeley right across the bay in Experimental Psychology. In 1979, he and his coauthor Amos Tversky published their seminal paper on Prospect Theory which started to change the way people reframed the argument around gains, losses, and decision-making under uncertainty. Several years later in 2002, Professor Kahneman was awarded the Nobel Prize largely on the work of Prospect Theory of. And Nobel Prize isn't always impressive; his perhaps more so because there isn't a Nobel Prize in psychology. He had to win his Nobel Prize in economics. And as far as I know, there's only one other person, one other psychologist, who's won a Nobel Prize and that's Ivan Pavlov. He may be a physiologist, we could argue about that. Years later, in 2007, Psychologist tried to reclaim Professor Kahneman as one of their own when the American Psychological Association awarded him Lifetime Distinguished Contribution Award. And today he is a Senior Scholar at the Woodrow Wilson School of Public and International Affairs at Princeton University and he's here to talk about his new book Thinking Fast and Slow. Now Google's mission which we all know is to take the world's information and to make it more useful and universally accessible. And all information, all knowledge, is important, but I think some again is more important than others. Because the information that he'll present today I think it's very personal; it's about each of us. And, if you'll listen carefully it's going to change the way you think about yourself and the world around you. So please join me in welcoming Professor Kahneman to Google. [Applause] >> Kahneman: Thank you. Well, I think intuition has been discussed a lot in recent years and I'll be talking about intuition. There are two camps in this discussion naturally there is the pro and the con. And of course, many people here will have read Malcolm Gladwell Blink which although it's not unconditional defense of intuition, it certainly gave people the impression that sometimes we magically know things without knowing why we know them. Within the discipline of psychology and the decision making there is a group and it is headed by a very interesting figure called Gary Kline who wrote a book that I recommend. Its Sources of Power is one of his books that I would recommend the most warmly. And they are great believers in expert intuition. The other side there are skeptics about intuition in general and including expert intuition. And I have long been counted as one of the skeptics because my early work with Amos Tversky was about intuitive errors and flaws and biases of intuitive thinking. Today you find that discussion in many places and for example in medicine among the popular writers; two writers both of whom write for the New Yorker, Jerome Groopman and Atul Gawande. They clearly differ. Atul Gawande is in favor of formal systems, very skeptical about human judgment and wanting to prove all the time and Jerome Groopman being in fact, although he doesn't quite admit he really likes good old fashioned medical intuition. Of course he likes physicians well-educated. But he doesn't like formal system and the issue in medicine is "What are the role of evidence based medicine and how do you allocate that with the function of intuition?" The background actually, part of the background for what I'll talk about today is a strange collaboration in which I engaged with about eight years with Gary Klein, whom I mentioned. He is a guru of a group of people who really, I wouldn't say they despise what I do but they certainly don't like what I do because they think that the emphasis and biases of judgment has drawn an unjustly unfavorable picture of the human mind. And by and large I am inclined to agree. Seven or eight years ago I invited him and we worked together for a number of years trying to figure out where is the boundary? Where is intuition marvelous and where is it flawed? And I think we can tell. And we wrote a paper at the end of six or seven years with a lot of vicissitudes that we went through since we basically don't agree. We wrote a paper the title of which was A Failure to Disagree, because on the substance I think we know and we both agree where you can trust intuition and where you cannot. Emotionally we haven't changed. He still hates the biases and doesn't think that errors of experts are very funny and I think that errors of experts are quite funny [laughter] so that's a difference right there. There are two modes of thinking that all of us are familiar with. And there is one mode, one way for thoughts that come to mind and listen to this. You know about this lady that she's I think adjust as quickly as you know her hair is dark. And it's interesting to dwell a bit about this. It is this is not something that the judgment that she is angry, the impression that she is angry. Doesn't feel like something you did. It feels like something that happens. It happens to me. We have the basic experience is a passive experience in those judgments. And that is true of perception, when we see the world we don't decide to see it. It is true of impression. And it is true in general what we call intuitive thinking. It just happens. It comes from somewhere. And we are not the author of it. Now, there is another way that thoughts come to mind and here I suppose essentially nothing came to your mind, but the answer is 408. To produce the 408, requires a completely different kind of operation. You have to retrieve the program that you learned in school. The program consists of steps. You have to go through the steps. You've got to pay attention successively to partial products and so on. And keep things in mind and keep the whole program in mind. This is how it works. This is something that you do. It is not something that happens to you. And there are many indications that this is how it works. One is that Physiology indicates and this is how it works: pupil dilates. This is something that I studies many, many years ago that people really on a program like that if you're on a problem like that if you're going to do it in your head, your pupil will dilate. The area will increase by about 50% as soon as you engage in that. And it will stay dilated as long as you're working and it will sort of collapse back to normal size either when you quit or when you find the answer. So this is another way thoughts come to mind. And this is definitely not the intuitive way. Here we are we feel a sense of urgency. We feel something deliberate is happening and a very important aspect of it this is effortful and what psychologists mean by effort is basically, if you want the quick introduction to what effort is, this is something you cannot do while making a left turn into traffic. You cannot do it and you shouldn't try. And the reason is that there is limited capacity to exert effort. And if you are engaged that capacity or those resources at one task less is available for another task. Now, there is another function of System 2. And here I'm going to tell you a riddle. Most of you are familiar with it. A bat and a ball together costs 1.10. The bat costs more than the ball. Of course how much does the ball cost? How many people know this riddle by the way? Oh, okay. So it's still usable. The point about this riddle is that the number came to your mind. And the number is ten cents. And everybody just, I think. Maybe here they're exception, very few exceptions. People confess that the number ten cents immediately came to mind. Now, it's wrong. Ten cents and dollar 10 is a dollar 20. The solution is five cents. What is interesting here is that at Princeton, at MIT at Harvard and I don't know about Stanford or CalTech about 50% of students asked this question of undergraduates say ten cents. And we learn something very interesting when somebody says ten cents. We learn that they didn't check because if they had checked, they wouldn't say ten cents. So, there is a sense of confidence that people have that these people in particular have and it brings us to another function of what I'll call System 2. System 1 is the intuitive one; they perform those automatic and activities and System 2 is the effortful one the one that the deliberate one. And the reason that I classify this as System 2 operation is that self-control and controlling your attention and deliberate exertion of effort are impaired when by other activities. So, if for example, a trivial example, if somebody is asked to retain seven digits in their head and you then give them a choice between chocolate cake, sinful chocolate cake and virtuous fruit salad they're more likely to choose the chocolate cake than they would if they didn't have seven digits in their head. It takes effort to control your impulses even such mild impulses as a preference for chocolate cake. So you should be aware of that difference between System 1 operations, the automatic ones and System 2 operations, the deliberate ones, it comes very clearly when in driving. So driving is a skill. And any skilled activity measure of skill is that things begin to happen automatically. So you can drive and conduct a conversation. You cannot make a left turn into traffic, but by and large, we can drive and talk. So driving is largely automatic. Braking, when there is any sign of danger, braking is completely automatic. That is, you can notice while you're braking, but you first respond so that the response is immediate, it is fully automatic. Now, in some places, not here where people drive in snow or ice, they learn about skids. And then, occasionally, you'll find yourself as a driver in a skid. And then System 2 will be mobilized because in a skid you're not supposed to do anything that comes naturally to you. You shouldn't brake and you shouldn't steer away from the skid. You should leave the brakes alone and steer into the skid, completely non-intuitive. Now, when people have a lot of practice with skids that too becomes automatic. So one thing that we can tell about System 1 and System 2 those two types of operations, is some of the basic innate operations, functions that we have such as having emotional reactions to things, all this is System 1. We don't choose to do it. It just happens to us. But also System 1 is where skill is. That is when we get to be skilled at something it becomes automatic and it demands your resources and we get to be very good at it. Now, the issue of intuition and here I'm not sure, but I suspect that Malcolm Gladwell really did us a disservice by giving us a sense there is magic to intuition. There really is no magic at all and we should understand how it works. Intuition and Herbert Simon who was Psychologist then and economist and a political scientist Nobel Laureate, Herbert Simon gave a very good definition about what intuition is. It is simply recognition. There is really no difference between the physician recognizing a disease, you know, a particular disease from a facial expression or something and a little child learning, pointing to something and saying doggie. The little child has no idea what the clues are but he just said. He just knows this is dog without knowing why he knows. And once you think about it this way, this really demystifies intuition to a very considerable extent. And it also leads you to sort of a solution to the problem Gary Klein and I were trying to solve. When can you trust intuition and when can't you? And then it becomes an issue of is the world regular enough so that you can learn to recognize things? Or and then did that particular individual have an opportunity to learn the regularities of the world? And so, the world of chess players is highly regular. And statistically, the world of poker players is very regular. So there is an element of chance, but there are rules and the mind is so set that if there are rules in the environment and we're exposed to them for a long time, and we get immediate feedback on what is right and wrong, or fairly immediate feedback, we would acquire those rules. So all of us have expert intuition even if we are not physicians and we're not master chess players. I recognize my wife's mood from one word on the telephone. You know, most of you can do that. There's people that you know very well. All of us recognize dangerous driver on the next lane. And you know we get cues and we don't necessarily know what is the cue but this person is driving erratically and could do something dangerous. And this is a lot of reinforced practice and we're very good at that. We can learn about those, there are differences. Among experts, among professionals, in the level of expertise that they have and they depend in the level of intuitive expertise that they can develop. So for example, compare anesthesiologists to radiologists. Anesthesiologists get very good feedback, an immediate feedback whenever they do anything wrong. You know they have those measurements in real time. Radiologists get really miserable feedback about whether they're right or wrong. So you could expect an anesthesiologist to develop intuition much more than you would expect radiologist to develop intuition. And so, that is part of the answer about intuitive expertise. We don't need to disagree about that because we know pretty much when intuitive expertise is likely to develop. And as I said, we also that means that intuitive expertise is not going to develop in a chaotic universe or in a chaotic world. So for example, I personally do not believe that that's stopped because people pick stocks to invest in can develop intuition because simply the market takes care of it. There isn't enough regularity in what's going to happen to prices for intuitions to develop. We also know about political forecasters when they forecast long-term, they are really no better than a dart-throwing monkey. And they are certainly not better than the average reader of the New York Times. Intuitions and the reason it's not the pundit's fault. And that research has been done with pundits and CIA analysts and regional experts. It is really not their fault that they cannot predict the long range future 10 or 15 years. They are quite good at short-term predictions. They are really not good at all in long-term predictions. It's not their fault. It's the fault of the world. The world is probably not predictable. And if the world is not predictable, then you are not going to predict it. When there are marginal situations where there is some predictability but poor formulas do better than individuals. That is the domain where formulas beat individuals regularly is a domain of fairly low predictability. Because when there are weak cues, people are not very good at picking them up and are not good at using them consistently. But formulas can be generated on the basis of experience and they will do a better job than individual judgment. Okay. Now, I've introduced you to System 1 and System 2 and I've told you something about skill and about skill in System 1. Now I'd like to point out something that we sometimes have intuitions and that applies to political forecasters and to stock pickers and to all of us. Quite frequently we have intuitions that are false. And they come up and come to mind and they are subjectively undistinguishable from expert intuitions. So I'm now talking of people who have intuitions that are not based on expertise. And they come. They're System 1 in the sense that they are effortless and automatic. And where do they come from? And that is what I'm going to try to illuminate, shed some light on in the rest of the talk. So I want to introduce you to System 1. And first of all, let me get one thing clear because I might forget. I use System 1 and System 2 those terms and very shocking terms in my discipline. You are really not supposed to do that. Because every psychologist gets told fairly early you're not supposed to explain what happens in the mind by invoking little agents inside the mind and explain what the mind does by what the little agents do. Those are homunculi and that's a bad word in psychology. I'm going to use System 1 and System 2 absolutely as homunculi. Now, what do I have to say in my defense? First of all, well, I'm warning you. Those are fictitious characters. They don't exist. I don't believe there is such a thing as System 1 and System 2. Don't look for them in the brain, because they are not two systems in the brain of which one does one and the other does the other. So why am I using this terrible language? I'm using it because I think it's helpful. It fits the way our minds work and to explain the background of that decision of why I use System 1 and System 2, I refer you to a very good book. It's very entertaining. It's by Joshua Foer and it's called Moonwalking with Einstein. It came out earlier this year. And what the book is about. Joshua Foer, he's a science writer. And he went to the Memory Championship of the United States. You might not know there is such a thing but there is. So people memorize decks of cards and very, very long lists of things and perform feats that we think are completely extraordinary. Joshua Foer decided to find out what happens. And a year later he was actually the champion -- the Memory Champion of the United States. And the book is a story of how he did it. And basically the story which was known to the Greeks in some form is that memory is very, very good at something and terrible at other things. Memory is terrible at remembering lists. We're really not good at remembering lists. Memory is superb at remembering routes through space. That evolution, evolution has endowed us with an ability to remember routes and not lists. So now, you can trick yourself. If mentally you have a list and you want to remember the list, then you create a mental route and you distribute the items on your list along the route. And then, when you want to remember the deck of cards or whatever it is, then you go through your route and you pick out items one after the other, because that you can do. It turns out something very similar happens in another context. People are very good thinking about agents. The mind is set really beautifully to think about agent. Agents have traits. Agents have behaviors. We understand agents. We form global impressions of their personalities. We are really not very good at remembering sentences where the subject of the sentence is an abstract notion. But an agent is very, very good. So just remember whenever I say System 1 does X what I mean is x is a mental activity that can be performed without effort. You'll remember a lot more about System 1 if you think about it as doing things than if you think of those mental activities. It helps me think and I think it helps other people understand.