WEBVTT 00:12.740 --> 00:15.220 Professor Paul Bloom: I actually want to begin by 00:15.219 --> 00:17.789 going back to Freud and hitting a couple of loose ends. 00:17.790 --> 00:21.650 There was a point in my lecture on Wednesday where I skipped 00:21.651 --> 00:24.491 over some parts. I said, "We don't have time for 00:24.494 --> 00:26.324 this" and I just whipped past it. 00:26.320 --> 00:28.030 And I couldn't sleep over the weekend. 00:28.030 --> 00:30.020 I've been tormented. 00:30.020 --> 00:33.730 I shouldn't have skipped that and I want to hit--Let me tell 00:33.732 --> 00:35.182 you why I skipped it. 00:35.180 --> 00:39.090 The discussion I skipped was the discussion of why we would 00:39.093 --> 00:41.053 have an unconscious at all. 00:41.050 --> 00:45.020 So, I was talking about the scientifically respectable ideas 00:45.018 --> 00:48.848 of Freud and I want to talk about some new ideas about why 00:48.852 --> 00:51.142 there could be an unconscious. 00:51.140 --> 00:55.480 Now, the reason why I skipped it is I'm not sure this is the 00:55.477 --> 00:58.047 best way to look at the question. 00:58.050 --> 01:02.780 As we will learn throughout the course, by far the vast majority 01:02.778 --> 01:06.418 of what our brains do, the vast majority of what our 01:06.415 --> 01:09.575 minds do, is unconscious and we're unaware of it. 01:09.579 --> 01:13.929 So the right question to ask may not be, "Why are some things 01:13.932 --> 01:17.082 unconscious?" but rather, why is this tiny 01:17.082 --> 01:20.472 subset of mental life--why is this conscious? 01:20.470 --> 01:23.680 On the other hand, these claims about the utility 01:23.682 --> 01:26.832 of unconsciousness, I think, are provocative and 01:26.829 --> 01:29.499 interesting. So I just wanted to quickly 01:29.503 --> 01:30.753 share them with you. 01:30.750 --> 01:33.350 So, the question is, from an evolutionary 01:33.354 --> 01:36.484 standpoint, "Why would an unconscious evolve?" 01:36.480 --> 01:41.280 And an answer that some psychologists and biologists 01:41.281 --> 01:43.731 have given is deception. 01:43.730 --> 01:46.090 So, most animals do some deception. 01:46.090 --> 01:50.310 And deception defined broadly is simply to act or be in some 01:50.314 --> 01:53.894 way that fools others into believing or thinking or 01:53.894 --> 01:56.834 responding to something that's false. 01:56.830 --> 02:00.680 There's physical examples of deception. 02:00.680 --> 02:03.430 When threatened, chimpanzees--their hair stands 02:03.425 --> 02:06.885 up on end and that makes them look bigger to fool others to 02:06.886 --> 02:09.866 thinking they're more dangerous than they are. 02:09.870 --> 02:13.220 There's an angler fish at the bottom of the ocean that has a 02:13.217 --> 02:16.737 rod sticking up from the top of its head with a lure to capture 02:16.735 --> 02:20.195 other fish – to fool them in thinking that this is something 02:20.196 --> 02:22.916 edible and then to themselves be devoured. 02:22.919 --> 02:27.989 But humans, primates in general but particularly humans, 02:27.990 --> 02:30.480 are masters of deception. 02:30.479 --> 02:33.819 We use our minds and our behaviors and our actions 02:33.817 --> 02:37.837 continually to try to trick people into believing what's not 02:37.836 --> 02:39.986 true. We try to trick people, 02:39.989 --> 02:42.529 for instance, into believing that we're 02:42.531 --> 02:45.781 tougher, smarter, sexier, more reliable, 02:45.780 --> 02:49.950 more trustworthy and so on, than we really are. 02:49.949 --> 02:53.009 And a large part of social psychology concerns the way in 02:53.005 --> 02:56.225 which we present ourselves to other people so as to make the 02:56.225 --> 02:59.495 maximally positive impression even when that impression isn't 02:59.499 --> 03:01.949 true. At the same time, 03:01.953 --> 03:08.823 though, we've also evolved very good lie detection mechanisms. 03:08.819 --> 03:11.509 So not only is there evolutionary pressure for me to 03:11.511 --> 03:14.151 lie to you, for me to persuade you for instance, 03:14.150 --> 03:17.110 that if we're going to have a--if you are threatening me 03:17.105 --> 03:20.105 don't threaten me, I am not the sort of man you 03:20.108 --> 03:21.828 could screw around with. 03:21.830 --> 03:24.360 But there's evolutionary pressure for you to look and 03:24.363 --> 03:25.943 say, "No. You are the sort of man you 03:25.938 --> 03:26.898 could screw around with. 03:26.900 --> 03:30.880 I can tell." So how do you become a good 03:30.877 --> 03:33.047 liar? And here's where the 03:33.053 --> 03:34.733 unconscious comes in. 03:34.729 --> 03:38.789 The hypothesis is: the best lies are lies we tell 03:38.794 --> 03:41.834 ourselves. You're a better liar, 03:41.827 --> 03:45.857 more generally, if you believe the lie that 03:45.861 --> 03:50.041 you're telling. This could be illustrated with 03:50.043 --> 03:52.663 a story about Alfred Hitchcock. 03:52.660 --> 03:56.900 The story goes--He hated working with child actors but he 03:56.903 --> 04:00.013 often had to. And the story goes--He was 04:00.014 --> 04:04.044 dealing with a child actor who simply could not cry. 04:04.039 --> 04:07.219 And, finally frustrated, Hitchcock went to the actor, 04:07.219 --> 04:09.239 leaned over, whispered in his ear, 04:09.237 --> 04:13.087 "Your parents have left you and they're never coming back." 04:13.090 --> 04:14.970 The kid burst into tears. 04:14.969 --> 04:18.439 Hitchcock said, "Roll ‘em" and filmed the 04:18.435 --> 04:20.095 kid. And the kid, 04:20.101 --> 04:24.691 if you were to see him, you'd say, "That's--Boy, 04:24.691 --> 04:30.161 he's--he really looks as if he's sad" because he was. 04:30.160 --> 04:34.890 If I had a competition where I'd give $100,000 to the person 04:34.891 --> 04:38.421 who looks the most as if they are in pain, 04:38.420 --> 04:43.050 it is a very good tactic to take a pen and jam it into your 04:43.051 --> 04:47.761 groin because you will look extremely persuasively as if you 04:47.762 --> 04:51.182 are in pain. If I want to persuade you that 04:51.182 --> 04:55.112 I love you, would never leave you, you can trust me with 04:55.111 --> 04:59.541 everything, it may be a superb tactic for me to believe it. 04:59.540 --> 05:05.210 And so, this account of the evolution of the unconscious is 05:05.205 --> 05:08.815 that certain motivations and goals, 05:08.819 --> 05:12.639 particularly sinister ones, are better made to be 05:12.639 --> 05:17.649 unconscious because if a person doesn't know they have them they 05:17.652 --> 05:19.882 will not give them away. 05:19.879 --> 05:24.689 And this is something I think we should return to later on 05:24.687 --> 05:28.647 when we talk about social interaction and social 05:28.651 --> 05:32.121 relationships. One other thing on Freud--just 05:32.122 --> 05:34.662 a story of the falsification of Freud. 05:34.660 --> 05:39.660 I was taking my younger child home from a play date on Sunday 05:39.660 --> 05:44.410 and he asked me out of the blue, "Why can't you marry your 05:44.410 --> 05:46.660 mother or your father?" 05:46.660 --> 05:49.270 Now, that's actually a difficult question to ask--to 05:49.267 --> 05:51.817 answer for a child, but I tried my best to give him 05:51.824 --> 05:55.174 an answer. And then I said--then I thought 05:55.166 --> 06:00.586 back on the Freud lecture and so I asked him, "If you could marry 06:00.589 --> 06:03.809 anybody you want, who would it be?" 06:03.810 --> 06:07.380 imagining he'd make explicit the Oedipal complex and name his 06:07.383 --> 06:13.953 mother. Instead, he paused for a moment 06:13.948 --> 06:23.478 and said, "I would marry a donkey and a big bag of 06:23.476 --> 06:26.346 peanuts." [laughter] 06:26.351 --> 06:29.171 Both his parents are psychologists and he hates these 06:29.167 --> 06:32.197 questions and at times he just screws around with us. 06:32.200 --> 06:40.820 [laughter] Okay. Last class I started with Freud 06:40.821 --> 06:44.031 and now I want to turn to Skinner. 06:44.029 --> 06:47.189 And the story of Skinner and science is somewhat different 06:47.189 --> 06:48.629 from the story of Freud. 06:48.629 --> 06:54.459 Freud developed and championed the theory of psychoanalysis by 06:54.463 --> 06:57.203 himself. It is as close as you could 06:57.198 --> 06:59.898 find in science to a solitary invention. 06:59.899 --> 07:03.129 Obviously, he drew upon all sorts of sources and 07:03.132 --> 07:06.922 predecessors but psychoanalysis is identified as Freud's 07:06.915 --> 07:09.715 creation. Behaviorism is different. 07:09.720 --> 07:14.110 Behaviorism is a school of thought that was there long 07:14.114 --> 07:17.604 before Skinner, championed by psychologists 07:17.597 --> 07:20.497 like John Watson, for instance. 07:20.500 --> 07:24.230 Skinner came a bit late into this but the reason why we've 07:24.229 --> 07:28.349 heard of Skinner and why Skinner is so well known is he packaged 07:28.352 --> 07:31.022 these notions. He expanded upon them; 07:31.020 --> 07:33.150 he publicized them; he developed them 07:33.145 --> 07:36.845 scientifically and presented them both to the scientific 07:36.850 --> 07:40.830 community and to the popular community and sociologically in 07:40.825 --> 07:42.505 the 1960s and 1970s. 07:42.509 --> 07:45.209 In the United States, behaviorism was incredibly well 07:45.208 --> 07:46.608 known and so was Skinner. 07:46.610 --> 07:50.160 He was the sort of person you would see on talk shows. 07:50.160 --> 07:52.070 His books were bestsellers. 07:52.069 --> 07:59.769 Now, at the core of behaviorism are three extremely radical and 07:59.774 --> 08:02.264 interesting views. 08:02.259 --> 08:06.139 The first is a strong emphasis on learning. 08:06.139 --> 08:10.609 The strong view of behaviorism is everything you know, 08:10.611 --> 08:14.831 everything you are, is the result of experience. 08:14.830 --> 08:17.360 There's no real human nature. 08:17.360 --> 08:21.090 Rather, people are infinitely malleable. 08:21.089 --> 08:25.349 There's a wonderful quote from John Watson and in this quote 08:25.348 --> 08:29.678 John Watson is paraphrasing a famous boast by the Jesuits. 08:29.680 --> 08:34.530 The Jesuits used to claim, "Give me a child until the age 08:34.529 --> 08:37.819 of seven and I'll show you the man," 08:37.820 --> 08:41.580 that they would take a child and turn him into anything they 08:41.576 --> 08:44.156 wanted. And Watson expanded on this 08:44.163 --> 08:46.053 boast, Give me a dozen healthy 08:46.046 --> 08:48.836 infants, well-formed and my own specified world to bring them up 08:48.841 --> 08:51.551 and I'll guarantee to take any one at random and train them to 08:51.547 --> 08:54.117 become any type of specialist I might select--doctor, 08:54.120 --> 08:56.250 lawyer, artist, merchant, chief, 08:56.254 --> 08:59.834 and yes, even beggar-man and thief, regardless of his 08:59.833 --> 09:02.043 talents, penchants, tendencies, 09:02.037 --> 09:05.417 abilities, vocations and race of his ancestors. 09:05.419 --> 09:09.899 Now, you could imagine--You could see in this a tremendous 09:09.897 --> 09:13.827 appeal to this view because Watson has an extremely 09:13.826 --> 09:16.336 egalitarian view in a sense. 09:16.340 --> 09:20.050 If there's no human nature, then there's no sense in which 09:20.054 --> 09:24.094 one group of humans by dint of their race or their sex could be 09:24.094 --> 09:26.054 better than another group. 09:26.050 --> 09:27.500 And Watson was explicit. 09:27.500 --> 09:31.330 None of those facts about people will ever make any 09:31.325 --> 09:34.775 difference. What matters to what you are is 09:34.777 --> 09:37.867 what you learn and how you're treated. 09:37.870 --> 09:42.620 And so, Watson claimed he could create anybody in any way simply 09:42.616 --> 09:45.626 by treating them in a certain fashion. 09:45.630 --> 09:49.230 09:49.230 --> 09:55.420 A second aspect of behaviorism was anti-mentalism. 09:55.419 --> 09:59.149 And what I mean by this is the behaviorists were obsessed with 09:59.151 --> 10:01.721 the idea of doing science and they felt, 10:01.720 --> 10:05.680 largely in reaction to Freud, that claims about internal 10:05.681 --> 10:08.801 mental states like desires, wishes, goals, 10:08.798 --> 10:11.588 emotions and so on, are unscientific. 10:11.590 --> 10:15.290 These invisible, vague things can never form the 10:15.294 --> 10:17.584 basis of a serious science. 10:17.580 --> 10:21.340 And so, the behaviorist manifesto would then be to 10:21.339 --> 10:25.709 develop a science without anything that's unobservable and 10:25.713 --> 10:29.473 instead use notions like stimulus and response and 10:29.473 --> 10:34.233 reinforcement and punishment and environment that refer to real 10:34.231 --> 10:36.841 world and tangible events. 10:36.840 --> 10:41.280 Finally, behaviorists believed there were no interesting 10:41.279 --> 10:43.619 differences across species. 10:43.620 --> 10:48.090 A behaviorist might admit that a human can do things that a rat 10:48.086 --> 10:51.756 or pigeon couldn't but a behaviorist might just say, 10:51.759 --> 10:53.799 "Look. Those are just general 10:53.797 --> 10:57.267 associative powers that differ" or they may even deny it. 10:57.269 --> 10:59.199 They might say, "Humans and rats aren't 10:59.203 --> 11:00.173 different at all. 11:00.169 --> 11:03.949 It's just humans tend to live in a richer environment than 11:03.949 --> 11:05.799 rats." From that standpoint, 11:05.798 --> 11:08.308 from that theoretical standpoint, comes a 11:08.309 --> 11:10.569 methodological approach which is, 11:10.570 --> 11:15.040 if they're all the same then you could study human learning 11:15.040 --> 11:17.430 by studying nonhuman animals. 11:17.429 --> 11:19.529 And that's a lot of what they did. 11:19.530 --> 11:22.040 Okay. I'm going to frame my 11:22.044 --> 11:26.794 introduction--my discussion of behaviors in terms of the three 11:26.793 --> 11:31.313 main learning principles that they argue can explain all of 11:31.309 --> 11:34.939 human mental life, all of human behavior. 11:34.940 --> 11:37.910 And then, I want to turn to objections to behaviorism but 11:37.905 --> 11:41.025 these three principles are powerful and very interesting. 11:41.030 --> 11:45.890 11:45.890 --> 11:48.090 The first is habituation. 11:48.090 --> 11:50.960 This is the very simplest form of learning. 11:50.960 --> 11:55.870 And what this is is technically described as a decline in the 11:55.874 --> 12:00.304 tendency to respond to stimuli that are familiar due to 12:00.297 --> 12:02.097 repeated exposure. 12:02.100 --> 12:09.810 "Hey!" "Hey!" 12:09.809 --> 12:16.269 The sudden noise startles but as it--as you hear it a second 12:16.271 --> 12:18.901 time it startles less. 12:18.899 --> 12:20.949 The third time is just me being goofy. 12:20.950 --> 12:25.730 It's just--It's--You get used to things. 12:25.730 --> 12:28.000 And this, of course, is common enough in everyday 12:27.999 --> 12:31.279 life. We get used to the ticking of a 12:31.282 --> 12:37.192 clock or to noise of traffic but it's actually a very important 12:37.187 --> 12:42.137 form of learning because imagine life without it. 12:42.139 --> 12:44.839 Imagine life where you never got used to anything, 12:44.840 --> 12:48.200 where suddenly somebody steps forward and waves their hand and 12:48.203 --> 12:50.533 you'd go, "Woah," and then they wave 12:50.530 --> 12:53.380 their hand again and you'd go, "Whoah," and you 12:53.379 --> 12:56.289 keep--[laughter] And there's the loud ticking of 12:56.291 --> 13:00.281 a clock and you say, "Hmmm." 13:00.279 --> 13:05.029 And that's not the way animals or humans work. 13:05.030 --> 13:06.350 You get used to things. 13:06.350 --> 13:10.700 And it's actually critically important to get used to things 13:10.700 --> 13:15.120 because it's a useful adaptive mechanism to keep track on new 13:15.124 --> 13:16.824 events and objects. 13:16.820 --> 13:19.480 It's important to notice something when it's new because 13:19.481 --> 13:22.241 then you have to decide whether it's going to harm you, 13:22.240 --> 13:25.540 how to deal with it, to attend to it, 13:25.544 --> 13:28.854 but you can't keep on noticing it. 13:28.850 --> 13:31.380 And, in fact, you should stop noticing it 13:31.379 --> 13:34.729 after it's been in the environment for long enough. 13:34.730 --> 13:38.050 So, this counts as learning because it happens through 13:38.046 --> 13:39.886 experience. It's a way to learn through 13:39.894 --> 13:42.314 experience, to change your way of thinking through experience. 13:42.309 --> 13:47.379 And also, it's useful because harmful stimuli are noticed but 13:47.382 --> 13:52.452 when something has shown itself to be part of the environment 13:52.454 --> 13:55.164 you don't notice it anymore. 13:55.159 --> 13:59.499 The existence of habituation is important for many reasons. 13:59.500 --> 14:03.630 One thing it's important for is clever developmental 14:03.629 --> 14:07.839 psychologists have used habituation as a way to study 14:07.839 --> 14:10.969 people, creatures who can't talk like 14:10.965 --> 14:13.735 nonhuman animals, and young babies. 14:13.740 --> 14:18.010 And when I talk on Wednesday about developmental psychology 14:18.010 --> 14:22.130 I'll show different ways in which psychologists have used 14:22.134 --> 14:25.894 habituation to study the minds of young babies. 14:25.889 --> 14:31.649 The second sort of learning is known as classical conditioning. 14:31.649 --> 14:36.149 And what this is in a very general sense is the learning of 14:36.146 --> 14:40.716 an association between one stimulus and another stimulus, 14:40.720 --> 14:44.630 where stimulus is a technical term meaning events in the 14:44.626 --> 14:48.386 environment like a certain smell or sound or sight. 14:48.390 --> 14:53.870 It was thought up by Pavlov. 14:53.870 --> 14:58.830 This is Pavlov's famous dog and it's an example of scientific 14:58.832 --> 15:02.282 serendipity. Pavlov, when he started this 15:02.282 --> 15:06.052 research, had no interest at all in learning. 15:06.050 --> 15:08.390 He was interested in saliva. 15:08.389 --> 15:11.749 And to get saliva he had to have dogs. 15:11.750 --> 15:15.220 And he had to attach something to dogs so that their saliva 15:15.224 --> 15:17.744 would pour out so he could study saliva. 15:17.740 --> 15:22.240 No idea why he wanted to study saliva, but he then discovered 15:22.240 --> 15:24.800 something. What he would do is he'd put 15:24.798 --> 15:27.818 food powder in the dog's mouth to generate saliva. 15:27.820 --> 15:33.210 But Pavlov observed that when somebody entered the room who 15:33.210 --> 15:36.650 typically gave him the food powder, 15:36.649 --> 15:39.469 the dog--the food powder saliva would start to come out. 15:39.470 --> 15:44.570 And later on if you--right before or right during you give 15:44.568 --> 15:50.288 the dog some food – you ping a bell – the bell will cause the 15:50.293 --> 15:52.533 saliva to come forth. 15:52.529 --> 15:55.189 And, in fact, this is the apparatus that he 15:55.190 --> 15:56.710 used for his research. 15:56.710 --> 16:00.300 16:00.299 --> 16:05.389 He developed the theory of classical conditioning by making 16:05.391 --> 16:09.781 a distinction between two sorts of conditioning, 16:09.779 --> 16:13.719 two sorts of stimulus response relationships. 16:13.720 --> 16:15.890 One is unconditioned. 16:15.889 --> 16:18.649 An unconditioned is when an unconditioned stimulus gives 16:18.652 --> 16:20.462 rise to an unconditioned response. 16:20.460 --> 16:22.930 And this is what you start off with. 16:22.929 --> 16:26.529 So, if somebody pokes you with a stick and you say, 16:26.527 --> 16:30.117 "Ouch," because it hurts, the poking and the "ouch" is an 16:30.121 --> 16:33.211 unconditioned stimulus causing an unconditioned response. 16:33.210 --> 16:35.380 You didn't have to learn that. 16:35.379 --> 16:39.249 When Pavlov put food powder in the dog's mouth and saliva was 16:39.253 --> 16:42.423 generated, that's an unconditioned stimulus giving 16:42.416 --> 16:44.866 rise to an unconditioned response. 16:44.870 --> 16:48.510 But what happens through learning is that another 16:48.507 --> 16:53.127 association develops – that between the conditioned stimulus 16:53.129 --> 16:55.629 and the conditioned response. 16:55.629 --> 16:57.549 So when Pavlov, for instance--Well, 16:57.548 --> 16:58.958 when Pavlov, for instance, 16:58.958 --> 17:01.548 started before conditioning there was simply an 17:01.553 --> 17:04.453 unconditioned stimulus, the food in the mouth, 17:04.445 --> 17:06.665 and an unconditioned response, saliva. 17:06.670 --> 17:07.960 The bell was nothing. 17:07.960 --> 17:09.740 The bell was a neutral stimulus. 17:09.740 --> 17:14.690 But over and over again, if you put the bell and the 17:14.691 --> 17:18.481 food together, pretty soon the bell will 17:18.478 --> 17:22.128 generate saliva. And now the bell--When--You 17:22.131 --> 17:25.621 start off with the unconditioned stimulus, unconditioned 17:25.619 --> 17:28.089 response. When the conditioned stimulus 17:28.086 --> 17:31.556 and the unconditioned stimulus are brought together over and 17:31.556 --> 17:34.866 over and over again, pretty soon the conditioned 17:34.867 --> 17:37.547 stimulus gives rise to the response. 17:37.549 --> 17:41.719 And now it's known as the conditioned stimulus giving rise 17:41.716 --> 17:43.906 to the conditioned response. 17:43.910 --> 17:46.460 This is discussed in detail in the textbook but I also--I'm 17:46.460 --> 17:49.230 going to give you--Don't panic if you don't get it quite now. 17:49.230 --> 17:52.330 I'm going to give you further and further examples. 17:52.329 --> 17:55.859 So, the idea here is, repeated pairings of the 17:55.860 --> 18:00.570 unconditioned stimulus and the conditioned stimulus will give 18:00.568 --> 18:02.528 rise to the response. 18:02.529 --> 18:05.669 And there's a difference between reinforced trials and 18:05.667 --> 18:06.967 unreinforced trials. 18:06.970 --> 18:09.940 A reinforced trial is when the conditioned stimulus and the 18:09.943 --> 18:11.843 unconditioned stimulus go together. 18:11.839 --> 18:16.029 You're--and to put it in a crude way, you're teaching the 18:16.025 --> 18:18.935 dog that the bell goes with the food. 18:18.940 --> 18:25.570 An unreinforced trial is when you get the food without the 18:25.566 --> 18:27.936 bell. You're not teaching the dog 18:27.942 --> 18:29.032 this. And, in fact, 18:29.025 --> 18:32.185 once you teach an animal something, if you stop doing the 18:32.191 --> 18:35.981 teaching the response goes away and this is known as extinction. 18:35.980 --> 18:38.700 But here's a graph. 18:38.700 --> 18:42.330 If you get--They really count the number of cubic centimeters 18:42.333 --> 18:45.483 of saliva. The dog is trained so that when 18:45.482 --> 18:49.002 the bell comes on--Actually, I misframed it. 18:49.000 --> 18:52.120 I'll try again. When the bell comes connected 18:52.115 --> 18:55.085 with food, there's a lot of saliva. 18:55.089 --> 18:58.249 An unreinforced response is when the bell goes on but 18:58.254 --> 19:01.944 there's no food. So, it's--Imagine you're the 19:01.937 --> 19:05.327 dog. So, you get food in your mouth, 19:05.334 --> 19:09.314 "bell, food, bell, food," and now "bell." 19:09.309 --> 19:15.019 But next you get "bell, bell, bell." 19:15.020 --> 19:16.930 You give it up. You stop. 19:16.930 --> 19:21.820 You stop responding to the bell. 19:21.819 --> 19:25.419 A weird thing which is discussed in the textbook is if 19:25.416 --> 19:29.556 you wait a while and then you try it again with the bell after 19:29.556 --> 19:33.076 a couple of hours, the saliva comes back. 19:33.079 --> 19:36.539 This is known as spontaneous recovery. 19:36.539 --> 19:41.459 So, this all seems a very technical phenomena related to 19:41.461 --> 19:46.741 animals and the like but it's easy to see how it generalizes 19:46.741 --> 19:48.801 and how it extends. 19:48.799 --> 19:52.439 One interesting notion is that of stimulus generalization. 19:52.440 --> 19:56.200 And stimulus generalization is the topic of one of your 19:56.202 --> 19:58.922 articles in The Norton Reader, 19:58.920 --> 20:00.930 the one by Watson, John Watson, 20:00.928 --> 20:03.938 the famous behaviorist, who reported a bizarre 20:03.942 --> 20:07.292 experiment with a baby known as Little Albert. 20:07.290 --> 20:09.000 And here's the idea. 20:09.000 --> 20:12.000 Little Albert originally liked rats. 20:12.000 --> 20:14.450 In fact, I'm going to show you a movie of Little Albert 20:14.453 --> 20:15.593 originally liking rats. 20:15.590 --> 20:18.930 20:18.930 --> 20:20.140 See. He's okay. 20:20.140 --> 20:24.600 No problem. Now, Watson did something 20:24.597 --> 20:28.347 interesting. As Little Albert was playing 20:28.346 --> 20:30.596 with the rat, "Oh, I like rats, 20:30.603 --> 20:34.893 oh," Watson went behind the baby--this is the--it's in the 20:34.892 --> 20:38.732 chapter--and banged the metal bar right here . 20:38.730 --> 20:41.520 The baby, "Aah," screamed, started to sob. 20:41.520 --> 20:47.870 Okay. What's the unconditioned 20:47.874 --> 20:51.254 stimulus? Somebody. 20:51.250 --> 20:53.660 The loud noise, the bar, the bang. 20:53.660 --> 20:56.390 What's the unconditioned response? 20:56.390 --> 21:00.580 Crying, sadness, misery. 21:00.579 --> 21:06.499 And as a result of this, Little Albert grew afraid of 21:06.501 --> 21:10.841 the rat. So there--what would be the 21:10.841 --> 21:13.451 conditioned stimulus? 21:13.450 --> 21:15.790 The rat. What would be the conditioned 21:15.788 --> 21:17.098 response? Fear. 21:17.100 --> 21:21.380 Excellent. Moreover, this fear extended to 21:21.379 --> 21:24.769 other things. So, this is a very weird and 21:24.774 --> 21:26.044 unpersuasive clip. 21:26.039 --> 21:29.899 But the idea is--the clip is to make the point that the fear 21:29.901 --> 21:32.651 will extend to a rabbit, a white rabbit. 21:32.650 --> 21:35.550 So, the first part, Little Albert's fine with the 21:35.545 --> 21:37.725 white rabbit. The second part is after he's 21:37.731 --> 21:40.341 been conditioned and he's kind of freaked out with the white 21:40.338 --> 21:43.058 rabbit. The problem is in the second 21:43.055 --> 21:47.845 part they're throwing the rabbit at him but now he's okay. 21:47.850 --> 22:05.610 22:05.610 --> 22:08.260 [laughter] Is the mic on? 22:08.260 --> 22:11.910 Oh. This is fine. 22:11.910 --> 22:17.500 This is one of a long list of experiments that we can't do 22:17.499 --> 22:21.419 anymore. So, classical conditioning is 22:21.421 --> 22:24.871 more than a laboratory phenomena. 22:24.869 --> 22:30.859 The findings of classical conditioning have been extended 22:30.860 --> 22:36.640 and replicated in all sorts of animals including crabs, 22:36.636 --> 22:40.056 fish, cockroaches and so on. 22:40.059 --> 22:46.589 And it's been argued to be an extension of--it's argued to 22:46.592 --> 22:53.242 underlie certain interesting aspects of human responses. 22:53.240 --> 22:54.650 So, I have some examples here. 22:54.650 --> 22:56.770 One example is fear. 22:56.769 --> 23:01.179 So, the Little Albert idea--The Little Albert experiment, 23:01.180 --> 23:05.590 provides an illustration for how phobias could emerge. 23:05.589 --> 23:08.629 Some proportion of people in this room have phobias. 23:08.630 --> 23:11.610 Imagine you're afraid of dogs. 23:11.609 --> 23:15.929 Well, a possible story for the--for why you became afraid 23:15.925 --> 23:20.315 of dogs is that one day a dog came up and he was a neutral 23:20.318 --> 23:22.188 stimulus. No problem. 23:22.190 --> 23:24.780 And all of a sudden he bit you. 23:24.779 --> 23:28.229 Now the pain of a bite, being bit, and then the pain 23:28.225 --> 23:31.265 and fear of that is an unconditioned stimulus, 23:31.265 --> 23:33.085 unconditioned response. 23:33.089 --> 23:34.489 You're just born with that, "ow." 23:34.490 --> 23:38.700 But the presence of the dog there is a conditioned stimulus 23:38.699 --> 23:41.529 and so you grew to be afraid of dogs. 23:41.529 --> 23:45.749 If you believe this, this also forms the basis for 23:45.747 --> 23:50.737 ways for a theory of how you could make phobias go away. 23:50.740 --> 23:54.190 How do you make conditioned stimulus, conditioned response 23:54.190 --> 23:56.860 things go away? Well, what you do is you 23:56.864 --> 23:59.734 extinguish them. How do you extinguish them? 23:59.730 --> 24:04.250 Well, you show the thing that would cause you to have the fear 24:04.248 --> 24:06.988 without the unconditioned stimulus. 24:06.990 --> 24:09.150 Here's an illustration. 24:09.150 --> 24:11.800 It's a joke. Sorry. 24:11.799 --> 24:15.009 He's simultaneously confronting the fear of heights, 24:15.014 --> 24:18.674 snakes, and the dark because he's trapped in that thing and 24:18.669 --> 24:22.009 the logic is--the logic of--the logic is not bad. 24:22.010 --> 24:22.980 He's stuck in there. 24:22.980 --> 24:25.420 Those are all the--his conditioned stimulus. 24:25.420 --> 24:29.080 But nothing bad happens so his fear goes away. 24:29.079 --> 24:33.349 The problem with this is while he's stuck in there he has this 24:33.345 --> 24:37.745 screaming, horrific panic attack and then it makes his fear much 24:37.750 --> 24:40.000 worse. So, what they do now though, 24:39.998 --> 24:43.428 and we'll talk about this much later in the course when we talk 24:43.428 --> 24:46.748 about clinical psychology--but one cure for phobias does draw 24:46.746 --> 24:49.026 upon, in a more intelligent way, 24:49.028 --> 24:50.888 the behaviorist literature. 24:50.890 --> 24:55.580 So, the claim about a phobia is that there's a bad association 24:55.578 --> 24:59.878 between, say dog and fear, or between airplanes or snakes 24:59.881 --> 25:01.881 and some bad response. 25:01.880 --> 25:04.860 So, what they do is what's called, "systematic 25:04.857 --> 25:08.827 desensitization," which is they expose you to what causes you 25:08.828 --> 25:12.928 the fear but they relax you at the same time so you replace the 25:12.931 --> 25:16.511 aversive classical conditioned fear with something more 25:16.505 --> 25:18.485 positive. Traditionally, 25:18.491 --> 25:21.811 they used to teach people relaxation exercises but that 25:21.813 --> 25:23.293 proves too difficult. 25:23.289 --> 25:26.609 So nowadays they just pump you full of some drug to get you 25:26.609 --> 25:29.869 really happy and so you're really stoned out of your head, 25:29.871 --> 25:31.761 you're and this isn't so bad. 25:31.759 --> 25:36.109 It's more complicated than that but the notion is you can use 25:36.114 --> 25:40.404 these associative tools perhaps to deal with questions about 25:40.396 --> 25:45.856 fear, phobias and how they go away. 25:45.860 --> 25:50.920 Hunger. We'll spend some time in this 25:50.918 --> 25:54.038 course discussing why we eat and when we eat. 25:54.039 --> 25:56.899 And one answer to why we eat and when we eat is that there's 25:56.899 --> 25:59.709 cues in the environment that are associated with eating. 25:59.710 --> 26:02.580 And these cues generate hunger. 26:02.579 --> 26:05.789 For those of you who are trying to quit smoking, 26:05.787 --> 26:09.267 you'll notice that there's time--or to quit drinking 26:09.268 --> 26:13.158 there's times of the day or certain activities that really 26:13.158 --> 26:17.388 make you want to smoke or really make you want to drink. 26:17.390 --> 26:21.750 And from a behaviorist point of view this is because of the 26:21.746 --> 26:24.596 associative history of these things. 26:24.599 --> 26:29.209 More speculatively, classical conditioning has been 26:29.211 --> 26:34.471 argued to be implicated in the formation of sexual desire, 26:34.468 --> 26:36.588 including fetishes. 26:36.589 --> 26:40.199 So a behaviorist story about fetishes, for instance, 26:40.195 --> 26:43.655 is it's straightforward classical conditioning. 26:43.660 --> 26:49.080 Just as your lover's caress brings you to orgasm, 26:49.083 --> 26:53.493 your eyes happen to fall upon a shoe. 26:53.490 --> 26:57.320 Through the simple tools of classical conditioning then, 26:57.318 --> 27:01.288 the shoe becomes a conditioned stimulus giving rise to the 27:01.286 --> 27:04.346 conditioned response of sexual pleasure. 27:04.349 --> 27:08.119 This almost certainly is not the right story but again, 27:08.118 --> 27:11.048 just as in phobias, some ideas of classical 27:11.049 --> 27:15.379 conditioning may play some role in determining what we like and 27:15.377 --> 27:17.747 what we don't like sexually. 27:17.750 --> 27:20.880 And in fact, one treatment for pedophiles 27:20.884 --> 27:25.824 and rapists involved controlled fantasies during masturbation to 27:25.820 --> 27:30.130 shift the association from domination and violence, 27:30.130 --> 27:33.340 for instance, to develop more positive 27:33.343 --> 27:36.473 associations with sexual pleasure. 27:36.470 --> 27:39.910 So the strong classical conditioning stories about 27:39.906 --> 27:44.036 fetishes and fears sound silly and extreme and they probably 27:44.043 --> 27:47.763 are but at the same time classical conditioning can be 27:47.760 --> 27:51.760 used at least to shape the focus of our desires and of our 27:51.757 --> 27:54.687 interests. Final thought actually is--Oh, 27:54.686 --> 27:55.756 yeah. Okay. 27:55.759 --> 27:58.039 So, what do we think about classical conditioning? 27:58.039 --> 28:00.039 We talked about what habituation is for. 28:00.039 --> 28:01.709 What's classical conditioning for? 28:01.710 --> 28:04.230 Well, the traditional view is it's not for anything. 28:04.230 --> 28:05.500 It's just association. 28:05.500 --> 28:09.470 So, what happens is the UCS and the CS, the bell and the food, 28:09.470 --> 28:12.790 go together because they happen at the same time. 28:12.789 --> 28:16.959 And so classical conditioning should be the strongest when 28:16.961 --> 28:21.431 these two are simultaneous and the response to one is the same 28:21.425 --> 28:23.835 as the response to the other. 28:23.839 --> 28:27.419 This is actually no longer the mainstream view. 28:27.420 --> 28:29.750 The mainstream view is now a little bit more interesting. 28:29.750 --> 28:33.260 It's that what happens in classical conditioning is 28:33.257 --> 28:36.457 preparation. What happens is you become 28:36.460 --> 28:41.500 sensitive to a cue that an event is about to happen and that 28:41.499 --> 28:44.829 allows you to prepare for the event. 28:44.830 --> 28:47.390 This makes certain predictions. 28:47.390 --> 28:50.480 It predicts that the best timing is when the conditioned 28:50.481 --> 28:53.811 stimulus, which is the signal, comes before the unconditioned 28:53.814 --> 28:56.324 stimulus, which is what you have to prepare for. 28:56.319 --> 29:00.409 And it says the conditioned response may be different from 29:00.409 --> 29:02.489 the unconditioned response. 29:02.490 --> 29:04.410 So, move away from food. 29:04.410 --> 29:08.000 Imagine a child who's being beaten by his father. 29:08.000 --> 29:11.730 And when his father raises his hand he flinches. 29:11.730 --> 29:13.890 Well, that's classical conditioning. 29:13.890 --> 29:18.400 What happened in that case is he has learned that the raising 29:18.396 --> 29:22.676 of a hand is a signal that he is about to be hit and so he 29:22.677 --> 29:24.777 responds to that signal. 29:24.779 --> 29:29.239 His flinch is not the same response that one would give if 29:29.240 --> 29:31.750 one's hit. If you're hit, you don't flinch. 29:31.750 --> 29:33.540 If you're hit, you might feel pain or bounce 29:33.538 --> 29:34.368 back or something. 29:34.369 --> 29:37.179 Flinching is preparation for being hit. 29:37.180 --> 29:40.010 And, in general, the idea of what goes on in 29:40.005 --> 29:43.615 classical conditioning is that the response is sort of a 29:43.618 --> 29:46.428 preparation. The conditioned response is a 29:46.433 --> 29:49.113 preparation for the unconditioned stimulus. 29:49.109 --> 29:51.949 Classical conditioning shows up all over the place. 29:51.950 --> 29:54.760 As a final exercise, and I had to think about 29:54.755 --> 29:58.385 it--Has anybody here seen the movie "Clockwork Orange"? 29:58.390 --> 30:01.710 A lot of you. It's kind of a shocking movie 30:01.711 --> 30:06.271 and unpleasant and very violent but at its core one of the main 30:06.267 --> 30:09.057 themes is right out of Intro Psych. 30:09.060 --> 30:10.590 It's classical conditioning. 30:10.589 --> 30:14.519 And a main character, who is a violent murderer and 30:14.523 --> 30:19.483 rapist, is brought in by some psychologists for some therapy. 30:19.480 --> 30:22.360 And the therapy he gets is classical conditioning. 30:22.359 --> 30:25.089 In particular, what happens is he is given a 30:25.092 --> 30:28.652 drug that makes him violently ill, extremely nauseous. 30:28.650 --> 30:32.210 And then his eyes are propped open and he's shown scenes of 30:32.214 --> 30:34.964 violence. As a result of this sort of 30:34.955 --> 30:38.315 conditioning, he then – when he experiences 30:38.322 --> 30:42.992 real world violence – he responds with nausea and shock; 30:42.990 --> 30:50.230 basically, training him to get away from these acts of 30:50.227 --> 30:53.897 violence. In this example--Take a moment. 30:53.900 --> 30:54.570 Don't say it aloud. 30:54.570 --> 30:55.500 Just take a moment. 30:55.500 --> 30:59.660 What's the unconditioned stimulus? 30:59.660 --> 31:01.240 Okay. Anybody, what's the 31:01.238 --> 31:02.208 unconditioned stimulus? 31:02.210 --> 31:03.150 Somebody just say it. 31:03.150 --> 31:08.890 The drug. What's the unconditioned 31:08.887 --> 31:10.977 response? Nausea. 31:10.980 --> 31:13.590 What's the conditioned stimulus? 31:13.590 --> 31:17.740 Violence. What's the conditioned response? 31:17.740 --> 31:21.680 Perfect. The third and final type of 31:21.680 --> 31:27.050 learning is known as operant conditioning or instrumental 31:27.054 --> 31:30.484 conditioning. And this is the thing, 31:30.484 --> 31:35.564 this is the theory championed and developed most extensively 31:35.564 --> 31:39.054 by Skinner. What this is is learning the 31:39.046 --> 31:43.436 relationships between what you do and how successful or 31:43.437 --> 31:47.497 unsuccessful they are, learning what works and what 31:47.502 --> 31:49.432 doesn't. It's important. 31:49.430 --> 31:52.400 This is very different from classical conditioning and one 31:52.402 --> 31:55.582 way to see how this is different is for classical conditioning 31:55.584 --> 31:56.944 you don't do anything. 31:56.940 --> 32:01.380 You could literally be strapped down and be immobile and these 32:01.379 --> 32:04.799 connections are what you appreciate and you make 32:04.799 --> 32:06.909 connections in your mind. 32:06.910 --> 32:09.670 Instrumental conditioning is voluntary. 32:09.670 --> 32:15.350 You choose to do things and by dint of your choices. 32:15.349 --> 32:21.849 Some choices become more learned than others. 32:21.849 --> 32:26.989 So, the idea itself was developed in the nicest form by 32:26.993 --> 32:31.093 Thorndike who explored how animals learn. 32:31.089 --> 32:34.609 Remember behaviorists were entirely comfortable studying 32:34.613 --> 32:37.823 animals and drawing extrapolations to other animals 32:37.816 --> 32:41.026 and to humans. So, he would put a cat in a 32:41.033 --> 32:43.903 puzzle box. And the trick to a puzzle box 32:43.903 --> 32:48.083 is there's a simple way to get out but you have to kind of pull 32:48.080 --> 32:50.240 on something, some special lever, 32:50.235 --> 32:51.915 to make it pop open. 32:51.920 --> 32:56.430 And Thorndike noted that cats do not solve this problem 32:56.427 --> 33:00.147 through insight. They don't sit in the box for a 33:00.149 --> 33:04.229 while and mull it over and then figure out how to do it. 33:04.230 --> 33:07.500 Instead, what they do is they bounce all around doing 33:07.501 --> 33:11.341 different things and gradually get better and better at it. 33:11.339 --> 33:13.759 So, what they do is, the first time they might 33:13.761 --> 33:15.911 scratch at the bars, push at the ceiling, 33:15.914 --> 33:17.964 dig at the floor, howl, etc., etc. 33:17.960 --> 33:20.270 And one of their behaviors is pressing the lever. 33:20.269 --> 33:23.999 The lever gets them out of the box, but after more and more 33:23.995 --> 33:27.655 trials they stopped scratching at the bars, pushing at the 33:27.656 --> 33:29.066 ceiling and so on. 33:29.070 --> 33:31.420 They just pressed the lever. 33:31.420 --> 33:34.870 And if you graph it, they gradually get better and 33:34.866 --> 33:37.506 better. They throw out all of these 33:37.510 --> 33:39.000 behaviors randomly. 33:39.000 --> 33:43.840 Some of them get reinforced and those are the ones that survive 33:43.840 --> 33:48.600 and others don't get reinforced and those are the ones that go 33:48.603 --> 33:51.513 extinct. And it might occur to some of 33:51.513 --> 33:55.193 you that this seems to be an analogy with the Darwinian 33:55.186 --> 33:58.516 theory of natural selection where there's a random 33:58.520 --> 34:00.970 assortment of random mutations. 34:00.970 --> 34:04.610 And sexual selections give rise to a host of organisms, 34:04.612 --> 34:08.662 some of which survive and are fit and others which aren't. 34:08.659 --> 34:12.139 And in fact, Skinner explicitly made the 34:12.144 --> 34:16.704 analogy from the natural selection of species to the 34:16.701 --> 34:19.741 natural selection of behavior. 34:19.739 --> 34:23.299 So this could be summarized as the law of effect, 34:23.300 --> 34:27.600 which is a tendency to perform – an action's increased if 34:27.603 --> 34:30.203 rewarded, weakened if it's not. 34:30.199 --> 34:34.329 And Skinner extended this more generally. 34:34.329 --> 34:39.639 So, to illustrate Skinnerian theory in operant conditioning 34:39.643 --> 34:43.403 I'll give an example of training a pig. 34:43.400 --> 34:44.690 So here is the idea. 34:44.690 --> 34:50.510 You need to train a pig and you need to do so through operant 34:50.514 --> 34:53.704 conditioning. So one of the things you want 34:53.702 --> 34:57.352 to do is--The pig is going to do some things you like and some 34:57.346 --> 34:58.836 things you don't like. 34:58.840 --> 35:03.470 And so what you want to do, basically drawing upon the law 35:03.470 --> 35:08.020 of effect, is reinforce the pig for doing good things. 35:08.019 --> 35:10.229 Suppose you want the pig to walk forward. 35:10.230 --> 35:14.140 So, you reinforce the pig for walking forward and you punish 35:14.137 --> 35:16.187 the pig for walking backward. 35:16.190 --> 35:19.260 And if you do that over the fullness of time, 35:19.259 --> 35:22.889 your reinforcement and punishment will give rise to a 35:22.886 --> 35:24.696 pig who walks forward. 35:24.699 --> 35:28.449 There's two--One technical distinction that people love to 35:28.448 --> 35:32.588 put on Intro Psych exams is that the difference between positive 35:32.590 --> 35:35.550 reinforcement and negative reinforcement. 35:35.550 --> 35:40.460 Reinforcement is something that makes the behavior increase. 35:40.460 --> 35:44.510 Negative reinforcement is very different from punishment. 35:44.510 --> 35:47.180 Negative reinforcement is just a type of reward. 35:47.179 --> 35:51.329 The difference is in positive reinforcement you do something; 35:51.329 --> 35:55.369 in negative reinforcement you take away something aversive. 35:55.369 --> 35:59.499 So, imagine the pig has a heavy collar and to reward the pig for 35:59.500 --> 36:02.910 walking forward you might remove the heavy collar. 36:02.909 --> 36:07.609 So, these are the basic techniques to train an animal. 36:07.610 --> 36:11.840 But it's kind of silly because suppose you want your pig to 36:11.836 --> 36:14.206 dance. You don't just want your pig to 36:14.211 --> 36:17.501 walk forward. You want your pig to dance. 36:17.500 --> 36:21.500 Well, you can't adopt the policy of "I'm going to wait for 36:21.503 --> 36:25.723 this pig to dance and when it does I'm going to reinforce it" 36:25.717 --> 36:29.367 because it's going to take you a very long time. 36:29.369 --> 36:33.669 Similarly, if you're dealing with immature humans and you 36:33.673 --> 36:36.443 want your child to get you a beer, 36:36.440 --> 36:39.810 you can't just sit, wait for the kid to give you a 36:39.806 --> 36:42.276 beer and uncap the bottle and say, 36:42.280 --> 36:43.510 "Excellent. Good. 36:43.510 --> 36:48.000 Hugs." You've got to work your way to 36:47.996 --> 36:50.406 it. And the act of working your way 36:50.406 --> 36:52.306 to it is known as shaping. 36:52.309 --> 36:56.429 So, here is how to get a pig to dance. 36:56.429 --> 37:00.529 You wait for the pig to do something that's halfway close 37:00.533 --> 37:04.053 to dancing, like stumbling, and you reward it. 37:04.050 --> 37:07.490 Then it does something else that's even closer to dancing 37:07.491 --> 37:08.721 and you reward it. 37:08.719 --> 37:12.389 And you keep rewarding it as it gets closer to closer. 37:12.389 --> 37:16.189 Here's how to get your child to bring you some beer. 37:16.190 --> 37:19.080 You say, "Johnny, could you go to the kitchen and 37:19.084 --> 37:20.294 get me some beer?" 37:20.289 --> 37:22.969 And he walks to the kitchen and then he forgets why he's there 37:22.974 --> 37:24.034 and you run out there. 37:24.030 --> 37:24.950 "You're such a good kid. 37:24.950 --> 37:26.960 Congratulations. Hugs." 37:26.960 --> 37:30.540 And then you get him to--and then finally you get him to also 37:30.542 --> 37:33.172 open up the refrigerator and get the beer, 37:33.170 --> 37:36.160 open the door, get the--and in that way you 37:36.161 --> 37:39.511 can train creatures to do complicated things. 37:39.510 --> 37:41.980 Skinner had many examples of this. 37:41.980 --> 37:44.390 Skinner developed, in World War II, 37:44.393 --> 37:46.243 a pigeon guided missile. 37:46.239 --> 37:50.449 It was never actually used but it was a great idea. 37:50.449 --> 37:54.249 And people, in fact--The history of the military in the 37:54.252 --> 37:57.772 United States and other countries includes a lot of 37:57.772 --> 38:01.502 attempts to get animals like pigeons or dolphins to do 38:01.504 --> 38:05.804 interesting and deadly things through various training. 38:05.800 --> 38:08.770 More recreational, Skinner was fond of teaching 38:08.771 --> 38:10.581 animals to play Ping-Pong. 38:10.579 --> 38:13.159 And again, you don't teach an animal to play Ping-Pong by 38:13.161 --> 38:15.791 waiting for it to play Ping-Pong and then rewarding it. 38:15.789 --> 38:24.059 Rather, you reward approximations to it. 38:24.059 --> 38:26.529 And basically, there are primary reinforcers. 38:26.530 --> 38:29.860 There are some things pigs naturally like, 38:29.857 --> 38:31.477 food for instance. 38:31.480 --> 38:34.550 There are some things pigs actually automatically don't 38:34.554 --> 38:36.494 like, like being hit or shocked. 38:36.489 --> 38:39.439 But in the real world when dealing with humans, 38:39.443 --> 38:41.823 but even when dealing with animals, 38:41.820 --> 38:45.960 we don't actually always use primary reinforcers or negative 38:45.958 --> 38:49.338 reinforcers. What we often use are things 38:49.339 --> 38:52.509 like--for my dog saying, "Good dog." 38:52.510 --> 38:56.970 Now, saying "Good dog" is not something your dog has been 38:56.972 --> 39:00.162 built, pre-wired, to find pleasurable. 39:00.159 --> 39:03.889 But what happens is you can do a two-step process. 39:03.889 --> 39:07.699 You can make "Good dog" positive through classical 39:07.695 --> 39:10.765 conditioning. You give the dog a treat and 39:10.770 --> 39:14.010 say, "Good dog." Now the phrase "good dog" will 39:14.014 --> 39:16.034 carry the rewarding quality. 39:16.030 --> 39:19.190 And you could use that rewarding quality in order to 39:19.188 --> 39:21.358 train it. And through this way 39:21.364 --> 39:25.624 behaviorists have developed token economies where they get 39:25.624 --> 39:29.664 nonhuman animals to do interesting things for seemingly 39:29.660 --> 39:32.650 arbitrary rewards like poker chips. 39:32.650 --> 39:38.150 And in this way you can increase the utility and ease of 39:38.150 --> 39:42.010 training. Finally, in the examples we're 39:42.005 --> 39:47.605 giving, whenever the pig does something you like you reinforce 39:47.608 --> 39:50.938 it. But that's not how real life 39:50.936 --> 39:53.736 works. Real life for both humans and 39:53.742 --> 39:58.402 animals involved cases where the reinforcement doesn't happen all 39:58.403 --> 40:02.123 the time but actually happens according to different 40:02.117 --> 40:04.597 schedules. And so, there is the 40:04.599 --> 40:08.209 distinction between fixed schedules versus ratios – 40:08.213 --> 40:11.553 variable schedules and ratio versus interval. 40:11.550 --> 40:13.600 And this is something you could print out to look at. 40:13.599 --> 40:15.419 I don't need to go over it in detail. 40:15.420 --> 40:20.690 The difference between ratio is a reward every certain number of 40:20.692 --> 40:23.372 times somebody does something. 40:23.369 --> 40:28.929 So, if every tenth time your dog brought you the newspaper 40:28.932 --> 40:33.352 you gave it hugs and treats; that's ratio. 40:33.349 --> 40:35.859 An interval is over a period of time. 40:35.860 --> 40:40.020 So, if your dog gives you--if your dog, I don't know, 40:40.015 --> 40:44.245 dances for an hour straight, that would be an interval 40:44.250 --> 40:47.170 thing. And fixed versus variable 40:47.171 --> 40:52.011 speaks to whether you give a reward on a fixed schedule, 40:52.010 --> 40:53.580 every fifth time, or variable, 40:53.576 --> 40:56.866 sometimes on the third time, sometimes on the seventh time, 40:56.870 --> 40:59.260 and so on. And these are--There are 40:59.261 --> 41:02.071 examples here and there's no need to go over them. 41:02.070 --> 41:05.220 It's easy enough to think of examples in real life. 41:05.219 --> 41:11.719 So, for example, a slot machine is variable 41:11.721 --> 41:15.031 ratio. It goes off after it's been hit 41:15.028 --> 41:16.828 a certain number of times. 41:16.829 --> 41:19.289 It doesn't matter how long it takes you for--to do it. 41:19.289 --> 41:21.659 It's the number of times you pull it down. 41:21.659 --> 41:24.489 But it's variable because it doesn't always go off on the 41:24.490 --> 41:26.310 thousandth time. You don't know. 41:26.310 --> 41:28.210 It's unpredictable. 41:28.210 --> 41:33.470 The slot machine is a good example of a phenomena known as 41:33.470 --> 41:36.700 the partial reinforcement effect. 41:36.700 --> 41:38.220 And this is kind of neat. 41:38.219 --> 41:42.099 It makes sense when you hear it but it's the sort of finding 41:42.100 --> 41:45.850 that's been validated over and over again with animals and 41:45.849 --> 41:49.179 nonhumans. Here's the idea. 41:49.179 --> 41:52.809 Suppose you want to train somebody to do something and you 41:52.808 --> 41:56.558 want the training such that they'll keep on doing it even if 41:56.564 --> 41:58.924 you're not training them anymore, 41:58.920 --> 42:01.050 which is typically what you want. 42:01.050 --> 42:06.700 If you want that, the trick is don't reinforce it 42:06.695 --> 42:10.235 all the time. Behaviors last longer if 42:10.244 --> 42:13.964 they're reinforced intermittently and this is known 42:13.961 --> 42:17.011 as "the partial reinforcement effect." 42:17.010 --> 42:19.160 Thinking of this psychologically, 42:19.156 --> 42:22.976 it's as if whenever you put something in a slot machine it 42:22.981 --> 42:25.531 gave you money, then all of a sudden it 42:25.530 --> 42:28.140 stopped. You keep on doing it a few 42:28.139 --> 42:30.129 times but then you say, "Fine. 42:30.130 --> 42:33.650 It doesn't work," but what if it gave you money one out of 42:33.651 --> 42:35.011 every hundred times? 42:35.010 --> 42:40.220 Now you keep on trying and because the reinforcement is 42:40.218 --> 42:45.998 intermittent you don't expect it as much and so your behavior 42:46.004 --> 42:51.024 will persist across often a huge amount of time. 42:51.020 --> 42:52.560 Here's a good example. 42:52.559 --> 42:57.139 What's the very worst thing to do when your kid cries to go 42:57.144 --> 43:01.814 into bed with you and you don't want him to go into bed with 43:01.807 --> 43:04.407 you? Well, one--The worst thing to 43:04.411 --> 43:08.151 do is for any--Actually, for any form of discipline with 43:08.150 --> 43:10.870 a kid is to say, "No, absolutely not. 43:10.870 --> 43:15.610 No, no, no, no." "Okay." 43:15.610 --> 43:19.270 And then later on the kid's going to say, 43:19.269 --> 43:24.939 "I want to do it again" and you say no and the kid keeps asking 43:24.941 --> 43:28.291 because you've put it, well, put it as in a 43:28.288 --> 43:30.518 psychological way, not the way the behaviorists 43:30.515 --> 43:32.175 would put it. The kid knows okay, 43:32.180 --> 43:34.850 he's not going to get it right away, he's going to keep on 43:34.851 --> 43:36.541 asking. And so typically, 43:36.538 --> 43:40.838 what you're doing inadvertently in those situations is you're 43:40.840 --> 43:44.210 exploiting the partial reinforcement effect. 43:44.210 --> 43:47.680 If I want my kid to do something, I should say yes one 43:47.675 --> 43:49.305 out of every ten times. 43:49.309 --> 43:52.779 Unfortunately, that's the evolution of 43:52.781 --> 43:55.491 nagging. Because you nag, 43:55.494 --> 43:59.154 you nag, you nag, the person says, 43:59.154 --> 44:03.594 "Fine, okay," and that reinforces it. 44:03.590 --> 44:07.880 If Skinner kept the focus on rats and pigeons and dogs, 44:07.883 --> 44:12.503 he would not have the impact that he did but he argued that 44:12.495 --> 44:17.185 you could extend all of these notions to humans and to human 44:17.187 --> 44:19.777 behavior. So for an example, 44:19.775 --> 44:23.805 he argued that the prison system needs to be reformed 44:23.807 --> 44:27.837 because instead of focusing on notions of justice and 44:27.840 --> 44:32.570 retribution what we should do is focus instead on questions of 44:32.570 --> 44:36.990 reinforcing good behaviors and punishing bad ones. 44:36.989 --> 44:41.349 He argued for the notions of operant conditioning to be 44:41.349 --> 44:46.269 extended to everyday life and argued that people's lives would 44:46.273 --> 44:49.913 become fuller and more satisfying if they were 44:49.905 --> 44:53.695 controlled in a properly behaviorist way. 44:53.700 --> 44:55.370 Any questions about behaviorism? 44:55.370 --> 45:01.680 45:01.679 --> 45:03.599 What are your questions about behaviorism? 45:03.600 --> 45:12.540 45:12.540 --> 45:16.050 [laughter] Yes. Student: 45:16.053 --> 45:20.213 [inaudible]--wouldn't there be extinction after a while? 45:20.210 --> 45:20.890 [inaudible] Professor Paul Bloom: 45:20.890 --> 45:23.310 Good question. The discussion was over using 45:23.312 --> 45:27.522 things like poker chips for reinforcement and the point is 45:27.523 --> 45:29.903 exactly right. Since the connection with the 45:29.903 --> 45:32.193 poker chips is established through classical conditioning, 45:32.190 --> 45:36.150 sooner or later by that logic the poker chips would lose their 45:36.151 --> 45:38.231 power to serve as reinforcers. 45:38.230 --> 45:42.730 You'd have to sort of start it up again, retrain again. 45:42.730 --> 45:46.180 If you have a dog and you say "Good dog" to reward the dog, 45:46.177 --> 45:48.077 by your logic, which is right, 45:48.079 --> 45:50.449 at some point you might as well give the dog a treat along with 45:50.450 --> 45:52.340 the "Good dog." Otherwise, "Good dog" is not 45:52.336 --> 45:53.436 going to cut it anymore. 45:53.440 --> 45:59.170 45:59.170 --> 46:01.700 Yes. Student: 46:01.703 --> 46:04.183 [inaudible] Professor Paul Bloom: 46:04.182 --> 46:06.662 As far as I know, Skinner and Skinnerian 46:06.662 --> 46:09.712 psychologists were never directly involved in the 46:09.713 --> 46:11.433 creation of prisons. 46:11.429 --> 46:14.019 On the other hand, the psychological theory of 46:14.018 --> 46:17.068 behaviorism has had a huge impact and I think a lot of 46:17.067 --> 46:20.517 people's ways of thinking about criminal justice and criminal 46:20.518 --> 46:23.508 law has been shaped by behaviorist principles. 46:23.510 --> 46:26.250 So for instance, institutions like mental 46:26.251 --> 46:30.291 institutions and some prisons have installed token economies 46:30.294 --> 46:33.314 where there's rewards for good behavior, 46:33.310 --> 46:34.900 often poker chips of a sort. 46:34.900 --> 46:36.980 And then you could cash them in for other things. 46:36.980 --> 46:40.610 And, to some extent, these have been shaped by an 46:40.613 --> 46:43.493 adherence to behaviorist principles. 46:43.490 --> 46:52.370 Okay. So, here are the three general 46:52.371 --> 46:55.841 positions of behaviorism. 46:55.840 --> 46:58.700 (1) That there is no innate knowledge. 46:58.700 --> 47:00.320 All you need is learning. 47:00.320 --> 47:04.680 (2) That you could explain human psychology without mental 47:04.683 --> 47:07.213 notions like desires and goals. 47:07.210 --> 47:10.880 (3) And that these mechanisms apply across all domains and 47:10.878 --> 47:12.228 across all species. 47:12.230 --> 47:15.310 47:15.309 --> 47:19.089 I think it's fair to say that right now just about everybody 47:19.087 --> 47:22.157 agrees all of these three claims are mistaken. 47:22.159 --> 47:28.149 First, we know that it's not true that everything is learned. 47:28.150 --> 47:31.470 There is considerable evidence for different forms of innate 47:31.465 --> 47:35.055 knowledge and innate desires and we'll look--and we'll talk about 47:35.062 --> 47:38.102 it in detail when we look at case studies like language 47:38.097 --> 47:40.657 learning, the development of sexual 47:40.655 --> 47:44.155 preference, the developing understanding of material 47:44.155 --> 47:46.975 objects. There's a lot of debate over 47:46.980 --> 47:51.640 how much is innate and what the character of the built-in mental 47:51.638 --> 47:55.778 systems are but there's nobody who doubts nowadays that a 47:55.779 --> 48:00.659 considerable amount for humans and other animals is built-in. 48:00.659 --> 48:04.869 Is it true that talking about mental states is unscientific? 48:04.869 --> 48:09.039 Nobody believes this anymore either. 48:09.039 --> 48:12.599 Science, particularly more advanced sciences like physics 48:12.596 --> 48:15.386 or chemistry, are all about unobservables. 48:15.389 --> 48:18.619 They're all about things you can't see. 48:18.619 --> 48:23.569 And it makes sense to explain complex and intelligent behavior 48:23.573 --> 48:28.693 in terms of internal mechanisms and internal representations. 48:28.690 --> 48:32.900 Once again, the computer revolution has served as an 48:32.902 --> 48:35.052 illustrative case study. 48:35.050 --> 48:38.070 If you have a computer that plays chess and you want to 48:38.069 --> 48:40.249 explain how the computer plays chess, 48:40.250 --> 48:44.580 it's impossible to do so without talking about the 48:44.582 --> 48:48.652 programs and mechanisms inside the computer. 48:48.650 --> 48:52.080 Is it true that animals need reinforcement and punishment to 48:52.075 --> 48:54.075 learn? No, and there's several 48:54.075 --> 48:57.875 demonstrations at the time of Skinner suggesting that they 48:57.879 --> 49:01.199 don't. This is from a classic study by 49:01.196 --> 49:05.136 Tolman where rats were taught to run a maze. 49:05.139 --> 49:07.699 And what they found was the rats did fine. 49:07.699 --> 49:10.989 They learn to run a maze faster and faster when they're 49:10.990 --> 49:14.770 regularly rewarded but they also learn to run a maze faster and 49:14.769 --> 49:17.389 faster if they are not rewarded at all. 49:17.389 --> 49:23.339 So the reward helps, but the reward is in no sense 49:23.342 --> 49:26.902 necessary. And here's a more sophisticated 49:26.896 --> 49:29.056 illustration of the same point. 49:29.059 --> 49:32.689 Professor Paul Bloom: And this is the sort of 49:32.685 --> 49:36.945 finding, an old finding from before most of you were born, 49:36.949 --> 49:40.939 that was a huge embarrassment for the Skinnerian theory, 49:40.940 --> 49:44.640 as it suggests that rats in fact had mental maps, 49:44.639 --> 49:48.849 an internal mechanism that they used to understand the world – 49:48.848 --> 49:52.248 entirely contrary to the behaviorist idea everything 49:52.254 --> 49:56.534 could be explained in terms of reinforcement and punishment. 49:56.530 --> 49:59.850 Finally, is it true that there's no animal-specific 49:59.854 --> 50:01.654 constraints for learning? 50:01.650 --> 50:03.580 And again, the answer seems to be "no." 50:03.579 --> 50:07.439 Animals, for instance, have natural responses. 50:07.440 --> 50:12.150 So, you could train a pigeon to peck for food but that's because 50:12.150 --> 50:15.590 pecking for food is a very natural response. 50:15.590 --> 50:20.270 It's very difficult to train it to peck to escape a situation. 50:20.269 --> 50:24.169 You can train it to flap its wings to escape a situation but 50:24.170 --> 50:28.070 it's very difficult to get it to flap its wings for food. 50:28.070 --> 50:31.390 And the idea is they have sort of natural responses that these 50:31.385 --> 50:34.315 learning situations might exploit and might channel, 50:34.320 --> 50:37.870 but essentially, they do have certain natural 50:37.873 --> 50:40.703 ways of acting towards the world. 50:40.699 --> 50:46.699 We know that not all stimuli and responses are created equal. 50:46.699 --> 50:51.409 So, the Gray textbook has a very nice discussion of the 50:51.413 --> 50:55.703 Garcia effect. And the Garcia effect goes like 50:55.700 --> 50:59.430 this. Does anybody here have any food 50:59.433 --> 51:02.113 aversions? I don't mean foods you don't 51:02.108 --> 51:06.218 like. I mean foods that really make 51:06.224 --> 51:10.214 you sick. Often food aversions in humans 51:10.207 --> 51:15.827 and other animals can be formed through a form of association. 51:15.829 --> 51:19.669 What happens is suppose you have the flu and you get very 51:19.674 --> 51:23.734 nauseous and then at the same point you eat some sashimi for 51:23.725 --> 51:26.825 the first time. The connection between being 51:26.833 --> 51:29.863 nauseous and eating a new food is very potent. 51:29.860 --> 51:34.150 And even if you know intellectually full well that 51:34.150 --> 51:39.580 the sashimi isn't why you became nauseous, still you'll develop 51:39.580 --> 51:42.470 an aversion to this new food. 51:42.469 --> 51:48.369 When I was younger – when I was a teenager – I drank this 51:48.373 --> 51:51.623 Greek liqueur, ouzo, with beer. 51:51.619 --> 51:55.609 I didn't have the flu at the time but I became violently ill. 51:55.610 --> 52:01.000 And as a result I cannot abide the smell of that Greek liqueur. 52:01.000 --> 52:05.270 Now, thank God it didn't develop into an aversion to beer 52:05.274 --> 52:07.874 but-- [laughter] Small miracles. 52:07.869 --> 52:11.689 But the smell is very distinctive and for me--was new 52:11.692 --> 52:13.812 to me. And so, through the Garcia 52:13.811 --> 52:16.051 effect I developed a strong aversion. 52:16.050 --> 52:19.820 What's interesting though is the aversion is special so if 52:19.821 --> 52:23.921 you take an animal and you give it a new food and then you give 52:23.922 --> 52:27.762 it a drug to make it nauseous it will avoid that food. 52:27.760 --> 52:32.100 But if you take an animal and you give it a new food and then 52:32.102 --> 52:36.302 you shock it very painfully it won't avoid the new food. 52:36.300 --> 52:39.710 And the idea is that a connection between what 52:39.714 --> 52:43.284 something tastes and getting sick is natural. 52:43.280 --> 52:45.460 We are hard wired to say, "Look. 52:45.460 --> 52:48.850 If I'm going to eat a new food and I'm going to get nauseous, 52:48.851 --> 52:50.661 I'm going to avoid that food." 52:50.659 --> 52:55.779 The Garcia effect is that this is special to taste and nausea. 52:55.780 --> 52:58.200 It doesn't extend more generally. 52:58.199 --> 53:02.559 Finally, I talked about phobias and I'll return to phobias later 53:02.564 --> 53:03.954 on in this course. 53:03.949 --> 53:08.539 But the claim that people have formed their phobias through 53:08.540 --> 53:12.340 classical conditioning is almost always wrong. 53:12.340 --> 53:15.820 Instead, it turns out that there are certain phobias that 53:15.818 --> 53:17.928 we're specially evolved to have. 53:17.929 --> 53:21.849 So, both humans and chimpanzees, for instance, 53:21.845 --> 53:26.365 are particularly prone to develop fears of snakes. 53:26.369 --> 53:29.659 And when we talk about the emotions later on in the course 53:29.659 --> 53:31.909 we'll talk about this in more detail. 53:31.909 --> 53:35.889 But what seems likely is the sort of phobias you're likely to 53:35.886 --> 53:39.796 have does not have much to do with your personal history but 53:39.797 --> 53:43.837 rather it has a lot to do with your evolutionary history. 53:43.840 --> 53:47.440 Finally, the other reading you're going to do for this 53:47.440 --> 53:51.240 part--section of the course is Chomsky's classic article, 53:51.244 --> 53:53.694 his "Review of Verbal Behavior." 53:53.690 --> 53:57.890 Chomsky is one of the most prominent intellectuals alive. 53:57.889 --> 54:01.379 He's still a professor at MIT, still publishes on language and 54:01.384 --> 54:03.164 thought, among other matters. 54:03.159 --> 54:06.749 And the excerpt you're going to read is from his "Review of 54:06.752 --> 54:07.932 Verbal Behavior." 54:07.929 --> 54:11.299 And this is one of the most influential intellectual 54:11.302 --> 54:14.942 documents ever written in psychology because it took the 54:14.938 --> 54:17.648 entire discipline of behaviorism and, 54:17.650 --> 54:21.380 more than everything else, more than any other event, 54:21.384 --> 54:25.624 could be said to have destroyed it or ended it as a dominant 54:25.622 --> 54:27.492 intellectual endeavor. 54:27.489 --> 54:30.929 And Chomsky's argument is complicated and interesting, 54:30.932 --> 54:34.642 but the main sort of argument he had to make is--goes like 54:34.635 --> 54:37.345 this. When it comes to humans, 54:37.349 --> 54:41.789 the notions of reward and punishment and so on that 54:41.785 --> 54:46.575 Skinner tried to extend to humans are so vague it's not 54:46.576 --> 54:49.906 science anymore. And remember the discussion we 54:49.907 --> 54:51.177 had with regard to Freud. 54:51.179 --> 54:55.069 What Skinner--What Chomsky is raising here is the concern of 54:55.072 --> 54:57.962 unfalsifiablity. So, here's the sort of example 54:57.960 --> 54:58.980 he would discuss. 54:58.980 --> 55:01.250 Skinner, in his book Verbal Behavior, 55:01.248 --> 55:04.358 talks about the question of why do we do things like talk to 55:04.361 --> 55:06.151 ourselves, imitate sounds, 55:06.148 --> 55:10.478 create art, give bad news to an enemy, fantasize about pleasant 55:10.481 --> 55:13.311 situations? And Skinner says that they all 55:13.310 --> 55:15.980 involve reinforcement; those are all reinforced 55:15.978 --> 55:18.918 behaviors. But Skinner doesn't literally 55:18.917 --> 55:23.567 mean that when we talk to ourselves somebody gives us food 55:23.571 --> 55:25.661 pellets. He doesn't literally mean even 55:25.664 --> 55:28.134 that when we talk to ourselves somebody pats us on the head and 55:28.133 --> 55:29.483 says, "Good man. Perfect. 55:29.480 --> 55:32.510 I'm very proud." What he means, 55:32.512 --> 55:35.052 for instance, in this case is well, 55:35.045 --> 55:38.915 talking to yourself is self-reinforcing or giving bad 55:38.918 --> 55:43.608 news to an enemy is reinforcing because it makes your enemy feel 55:43.610 --> 55:46.810 bad. Well, Chomsky says the problem 55:46.808 --> 55:48.868 is not that that's wrong. 55:48.870 --> 55:53.070 That's all true. It's just so vague as to be 55:53.067 --> 55:55.847 useless. Skinner isn't saying anything 55:55.850 --> 55:58.070 more. To say giving bad news to an 55:58.069 --> 56:02.049 enemy is reinforcing because it makes the enemy feel bad doesn't 56:02.051 --> 56:05.461 say anything different from giving bad news to an enemy 56:05.464 --> 56:09.324 feels good because we like to give bad news to an enemy. 56:09.320 --> 56:11.650 It's just putting it in more scientific terms. 56:11.650 --> 56:16.290 More generally, Chomsky suggests that the law 56:16.286 --> 56:22.606 of effect when applied to humans is either trivially true, 56:22.610 --> 56:28.230 trivially or uninterestingly true, or scientifically robust 56:28.228 --> 56:30.358 and obviously false. 56:30.360 --> 56:35.710 So, if you want to expand the notion of reward or 56:35.713 --> 56:40.623 reinforcement to anything, then it's true. 56:40.619 --> 56:44.929 So why did you come--those of you who are not freshmen--Oh, 56:44.927 --> 56:46.707 you--Why did you come? 56:46.710 --> 56:49.590 All of you, why did you come to Yale for a second semester? 56:49.590 --> 56:52.660 "Well, I repeated my action because the first semester was 56:52.659 --> 56:54.959 rewarding." Okay. 56:54.960 --> 56:56.300 What do you mean by that? 56:56.300 --> 56:59.410 Well, you don't literally mean that somebody rewarded you, 56:59.408 --> 57:00.988 gave you pellets and stuff. 57:00.989 --> 57:03.769 What you mean is you chose to come there for the second 57:03.773 --> 57:06.163 semester. And there's nothing wrong with 57:06.161 --> 57:09.441 saying that but we shouldn't confuse it with science. 57:09.440 --> 57:12.050 And more generally, the problem is you can talk 57:12.052 --> 57:15.182 about what other people do in terms of reinforcement and 57:15.175 --> 57:17.895 punishment and operant conditioning and classical 57:17.901 --> 57:20.521 conditioning. But in order to do so, 57:20.521 --> 57:24.371 you have to use terms like "punishment" and "reward" and 57:24.374 --> 57:28.654 "reinforcement" in such a vague way that in the end you're not 57:28.648 --> 57:30.888 saying anything scientific. 57:30.889 --> 57:36.609 So, behaviorism as a dominant intellectual field has faded, 57:36.614 --> 57:42.344 but it still leaves behind an important legacy and it still 57:42.339 --> 57:47.469 stands as one of the major contributions of twentieth 57:47.472 --> 57:49.942 century psychology. 57:49.940 --> 57:52.040 For one thing, it has given us a richer 57:52.042 --> 57:54.482 understanding of certain learning mechanisms, 57:54.476 --> 57:56.796 particularly with regard to nonhumans. 57:56.800 --> 57:59.660 Mechanisms like habituation, classical conditioning and 57:59.663 --> 58:02.603 operant conditioning are real; they can be scientifically 58:02.600 --> 58:04.720 studied; and they play an important role 58:04.715 --> 58:07.755 in the lives of animals and probably an important role in 58:07.759 --> 58:09.009 human lives as well. 58:09.010 --> 58:12.120 They just don't explain everything. 58:12.119 --> 58:15.559 Finally, and this is something I'm going to return to on 58:15.564 --> 58:19.084 Wednesday actually, behaviorists have provided 58:19.078 --> 58:23.978 powerful techniques for training particularly for nonverbal 58:23.981 --> 58:28.041 creatures so this extends to animal trainers. 58:28.039 --> 58:31.279 But it also extends to people who want to teach young children 58:31.280 --> 58:34.520 and babies and also want to help populations like the severely 58:34.521 --> 58:36.541 autistic or the severely retarded. 58:36.539 --> 58:38.979 Many of these behaviorist techniques have proven to be 58:38.979 --> 58:41.249 quite useful. And in that regard, 58:41.252 --> 58:45.672 as well as in other regards, it stands as an important 58:45.667 --> 58:46.997 contribution.