1 00:00:00 --> 00:00:15 2 00:00:15 --> 00:00:20 PROFESSOR: OK what I want to do for the first couple of minutes 3 00:00:20 --> 00:00:24 of today's lecture, well, I guess looking at the hand-out 4 00:00:24 --> 00:00:26 what I want to do is play fill- in- the- blank with this 5 00:00:26 --> 00:00:29 great picture of a neuron. 6 00:00:29 --> 00:00:32 I got to talk about the gross structure of the brain last 7 00:00:32 --> 00:00:34 time, but I didn't get to say anything about a neuron. 8 00:00:34 --> 00:00:42 Neurons are the, are brain cells. 9 00:00:42 --> 00:00:44 Not all are brain cells, right? 10 00:00:44 --> 00:00:48 This is going to be a neuron. 11 00:00:48 --> 00:00:55 At least half the cells in the brain would be in the category 12 00:00:55 --> 00:00:59 of glia, that's a word that comes from the word for glue. 13 00:00:59 --> 00:01:01 And all the years I was learning about this stuff, 14 00:01:01 --> 00:01:05 glia kind of got shoved into the category of like 15 00:01:05 --> 00:01:07 support staff, right? 16 00:01:07 --> 00:01:10 These were the guys who cleaned up after the neurons who were 17 00:01:10 --> 00:01:12 doing all the cool stuff. 18 00:01:12 --> 00:01:17 But it's becoming increasingly clear that glia have many 19 00:01:17 --> 00:01:22 functions to play in brain function beyond the merely 20 00:01:22 --> 00:01:26 vegetative, and if you go into neuro-science, odds are that 21 00:01:26 --> 00:01:29 you'll end up learning a lot more about glia than I did 22 00:01:29 --> 00:01:32 when I was taking the equivalent of course. 23 00:01:32 --> 00:01:36 But the main units, if you like computational units for the 24 00:01:36 --> 00:01:42 brain are neurons and so here's a quick tour of a sort of a 25 00:01:42 --> 00:01:44 canonical typical neuron. 26 00:01:44 --> 00:01:47 A typical neuron would collect information either from other 27 00:01:47 --> 00:01:53 neurons on from sense organs through its dendrites, the word 28 00:01:53 --> 00:01:58 comes from tree-like, because its branching structure. 29 00:01:58 --> 00:02:03 So all these little branches making connections with lots of 30 00:02:03 --> 00:02:06 other neurons or with sense organs in say the skin or 31 00:02:06 --> 00:02:12 something like that, and the information that the dendrites 32 00:02:12 --> 00:02:15 collect you can think of as being in the form of little 33 00:02:15 --> 00:02:19 pulses of excitation or inhibition. 34 00:02:19 --> 00:02:23 They can be either positive or negative in nature. 35 00:02:23 --> 00:02:26 They flow down towards the cell body here. 36 00:02:26 --> 00:02:28 The neuron is a cell like other cells. 37 00:02:28 --> 00:02:32 It does all those good cellular sorts of things, but for the 38 00:02:32 --> 00:02:37 purposes, for our purposes, its big job is to act as a sort of 39 00:02:37 --> 00:02:41 a summator and to ask, how excited am I? 40 00:02:41 --> 00:02:46 Am I, you know, if I sum up all these pluses and minuses, am I 41 00:02:46 --> 00:02:49 excited enough to want to tell other neurons about my 42 00:02:49 --> 00:02:51 level of excitement here? 43 00:02:51 --> 00:02:58 If the excitement passes a threshold, the neuron sends an 44 00:02:58 --> 00:03:08 action potential, a signal, an action potential -- no, that 45 00:03:08 --> 00:03:10 doesn't look right, does it? 46 00:03:10 --> 00:03:13 Well, potential, there we go. 47 00:03:13 --> 00:03:18 This is why there's a handout, right, because I can't spell 48 00:03:18 --> 00:03:21 under good circumstances, and I can't spell online at all. 49 00:03:21 --> 00:03:24 Anyway, that should say potential. 50 00:03:24 --> 00:03:28 It sends a signal down the axon, the long wire of 51 00:03:28 --> 00:03:31 the neuron is the axon. 52 00:03:31 --> 00:03:34 53 00:03:34 --> 00:03:39 That action potential has a couple of important properties. 54 00:03:39 --> 00:03:43 Property one is that it's of a single polarity. 55 00:03:43 --> 00:03:45 There aren't pluses and minuses, there's just 56 00:03:45 --> 00:03:48 a single polarity. 57 00:03:48 --> 00:03:52 And it's a fixed size. 58 00:03:52 --> 00:03:55 A more excited neuron does not produce bigger action 59 00:03:55 --> 00:03:58 potential, so how's a neuron going to tell another neuron 60 00:03:58 --> 00:04:00 that it's more excited? 61 00:04:00 --> 00:04:01 Would you guess? 62 00:04:01 --> 00:04:05 It's going to say make more action potential. 63 00:04:05 --> 00:04:12 So its frequency coating it's level of excitement. 64 00:04:12 --> 00:04:17 But action potentials are fixed size, and fixed sign electro 65 00:04:17 --> 00:04:21 chemical signals powering their way down this axon. 66 00:04:21 --> 00:04:27 These bumps wrapping around the axon are actually 67 00:04:27 --> 00:04:28 another cell type. 68 00:04:28 --> 00:04:35 They're a form of glia known as myelin. 69 00:04:35 --> 00:04:40 They act as, it acts as insulation, keeping the signal 70 00:04:40 --> 00:04:44 in one neuron separate from the signal in others, and it also 71 00:04:44 --> 00:04:46 acts to speed transmission. 72 00:04:46 --> 00:04:51 There are a number of neurological diseases whose 73 00:04:51 --> 00:04:54 cause is not a problem with the neuron, but a 74 00:04:54 --> 00:04:55 problem with the myelin. 75 00:04:55 --> 00:04:58 De-myelinating diseases, like multiple sclerosis, for 76 00:04:58 --> 00:05:02 example, have their affect because the insulation is 77 00:05:02 --> 00:05:07 breaking down, not because the nerve cells themselves 78 00:05:07 --> 00:05:08 are breaking down. 79 00:05:08 --> 00:05:14 That signal reaches the arborization of the axon. 80 00:05:14 --> 00:05:16 It then goes off and talks to a bunch of other neurons. 81 00:05:16 --> 00:05:22 Or if this was a motor neuron, it would be talking to muscle. 82 00:05:22 --> 00:05:26 Typically it does not make a direct electrical contact. 83 00:05:26 --> 00:05:28 If you look at connections between stuff in your 84 00:05:28 --> 00:05:31 computer, those are direct electrical contacts. 85 00:05:31 --> 00:05:33 Not the way things work in the nervous system. 86 00:05:33 --> 00:05:39 In the nervous system, there's a small gap, called a synapse, 87 00:05:39 --> 00:05:42 and to signal from one neuron to another, an electrical 88 00:05:42 --> 00:05:47 signal coming down the axon causes chemicals to be 89 00:05:47 --> 00:05:49 released into the gap. 90 00:05:49 --> 00:05:55 They diffuse across the gap and bind to receptors on the other 91 00:05:55 --> 00:06:01 side, and that binding either produces a little plus or a 92 00:06:01 --> 00:06:03 little minus, depending on the nature of the chemical, the 93 00:06:03 --> 00:06:06 nature of the receptor, and then the whole process 94 00:06:06 --> 00:06:07 starts again. 95 00:06:07 --> 00:06:12 So you go from an essentially electrical signal to a chemical 96 00:06:12 --> 00:06:18 signal then back to an essentially electrical signal. 97 00:06:18 --> 00:06:22 These neuro trans, so called neurotransmitter chemicals are 98 00:06:22 --> 00:06:30 the targets of lots of the drugs that are used to modulate 99 00:06:30 --> 00:06:33 mental states, like antidepressant 100 00:06:33 --> 00:06:34 drugs, for example. 101 00:06:34 --> 00:06:38 And not just drugs over- the- counter, or not 102 00:06:38 --> 00:06:39 just prescription drugs. 103 00:06:39 --> 00:06:40 Let's see, what are you drinking there? 104 00:06:40 --> 00:06:44 Oh that's just tea, how boring. 105 00:06:44 --> 00:06:46 Well, I wasn't actually thinking she was probably 106 00:06:46 --> 00:06:50 putting away a margarita, but that drug would be 107 00:06:50 --> 00:06:51 working on a synapse. 108 00:06:51 --> 00:06:56 The caffeine that you are pouring into your brain is 109 00:06:56 --> 00:07:00 working on neurotransmitter and synaptic properties. 110 00:07:00 --> 00:07:03 That where you get your chance to affect large numbers 111 00:07:03 --> 00:07:06 of neurons at one time. 112 00:07:06 --> 00:07:09 We'll talk more about that later. 113 00:07:09 --> 00:07:12 Now if I look at my cute little diagram, yes you should have 114 00:07:12 --> 00:07:18 been able by now to fill in all the -- I wonder what that 115 00:07:18 --> 00:07:20 interesting thing is at the top, actually, the 116 00:07:20 --> 00:07:22 middle one at the top. 117 00:07:22 --> 00:07:24 What do you figure? 118 00:07:24 --> 00:07:26 Cell? 119 00:07:26 --> 00:07:28 It's not axon. 120 00:07:28 --> 00:07:28 It's not myelin. 121 00:07:28 --> 00:07:33 Those are the two at the bottom right and center. 122 00:07:33 --> 00:07:36 The one on the top right is pointing to synapse. 123 00:07:36 --> 00:07:38 The one at the top left is pointing to dendrites, and the 124 00:07:38 --> 00:07:43 one at the bottom left is pointing to the cell body. 125 00:07:43 --> 00:07:45 So -- 126 00:07:45 --> 00:07:45 AUDIENCE: [UNINTELLIGIBLE] 127 00:07:45 --> 00:07:47 PROFESSOR: Well, the one on the bottom left, I figure, 128 00:07:47 --> 00:07:49 is pointing to the soma, or cell body. 129 00:07:49 --> 00:07:52 I think the one at the top middle is pointing 130 00:07:52 --> 00:07:54 to the whole thing. 131 00:07:54 --> 00:07:55 AUDIENCE: Neuron. 132 00:07:55 --> 00:07:56 PROFESSOR: Neuron, yeah. 133 00:07:56 --> 00:08:00 AUDIENCE: [UNINTELLIGIBLE] 134 00:08:00 --> 00:08:02 PROFESSOR: Oh maybe, ah, yes, thank you. 135 00:08:02 --> 00:08:05 Oh, somebody's been doing their reading. 136 00:08:05 --> 00:08:08 Yes, OK, she, you are correct. 137 00:08:08 --> 00:08:10 So the top middle is almost undoubtedly pointing to the 138 00:08:10 --> 00:08:12 axon, that whole long thing. 139 00:08:12 --> 00:08:19 And the bottom, what she's pointing out is that the bottom 140 00:08:19 --> 00:08:27 middle one is pointing to the valleys amongst the bumps, and 141 00:08:27 --> 00:08:36 those are called the Nodes of Ranvier. 142 00:08:36 --> 00:08:40 Undoubtedly named after, you know, Joe Ranvier, who I 143 00:08:40 --> 00:08:41 don't know anything about. 144 00:08:41 --> 00:08:48 But the way that myelin speeds up transmission is it makes it 145 00:08:48 --> 00:08:51 possible for the action potential, rather than just 146 00:08:51 --> 00:08:55 going down the axon in a nice smooth fashion, it jumps 147 00:08:55 --> 00:08:58 from node to node. 148 00:08:58 --> 00:09:05 And so that's why the nodes are interesting. 149 00:09:05 --> 00:09:07 OK, I'm glad we've solved that. 150 00:09:07 --> 00:09:09 You would have thought I would have thought about that before 151 00:09:09 --> 00:09:12 putting the thing on the handout. 152 00:09:12 --> 00:09:20 OK, any other questions about neurons or things, yes -- 153 00:09:20 --> 00:09:21 AUDIENCE: So, soma, is that boring cell stuff happening 154 00:09:21 --> 00:09:22 all over the place? 155 00:09:22 --> 00:09:23 PROFESSOR: I mean, well, there's boring cell stuff 156 00:09:23 --> 00:09:23 happening all over the place. 157 00:09:23 --> 00:09:25 We shouldn't, of course call it boring cell stuff, because then 158 00:09:25 --> 00:09:28 guys in like, course seven come in and, well, you know, put 159 00:09:28 --> 00:09:30 a hit on us and things. 160 00:09:30 --> 00:09:36 But yeah, neurons are cells like other cells and they have 161 00:09:36 --> 00:09:39 to do all the, you know, respiratory things that 162 00:09:39 --> 00:09:41 other cells have to do. 163 00:09:41 --> 00:09:45 But, you know, our interest in them, of course, is as 164 00:09:45 --> 00:09:48 little communication and computational units. 165 00:09:48 --> 00:09:48 Yes? 166 00:09:48 --> 00:09:51 AUDIENCE: What is the myelin, exactly? 167 00:09:51 --> 00:09:54 PROFESSOR: It's another cell type that wraps around the 168 00:09:54 --> 00:10:01 axon and acts as insulation and speed bumps, I guess. 169 00:10:01 --> 00:10:03 You think of is these as the speed bumps, except they 170 00:10:03 --> 00:10:07 speed things up rather than slowing things down. 171 00:10:07 --> 00:10:11 Boy I bet that just confused matters. 172 00:10:11 --> 00:10:21 OK that said, what I want to today is to talk about 173 00:10:21 --> 00:10:24 why we do anything. 174 00:10:24 --> 00:10:29 It's the general topic of motivation. 175 00:10:29 --> 00:10:35 But, you might, well, you might ask a question 176 00:10:35 --> 00:10:37 like, why do you eat? 177 00:10:37 --> 00:10:40 And you say, well, you got to eat because you need -- if 178 00:10:40 --> 00:10:43 you don't eat, you die. 179 00:10:43 --> 00:10:43 AUDIENCE: Prove it. 180 00:10:43 --> 00:10:45 PROFESSOR: Prove it, right. 181 00:10:45 --> 00:10:47 That's not a stupid point. 182 00:10:47 --> 00:10:50 He meant it as a stupid point, but it's not a stupid point. 183 00:10:50 --> 00:10:52 Does a rat -- why does a rat eat? 184 00:10:52 --> 00:10:54 Does it know it's going to die? 185 00:10:54 --> 00:10:56 Is a rat sort of sitting there, you know, with existential 186 00:10:56 --> 00:11:01 concerns about it's -- I don't think so, particularly. 187 00:11:01 --> 00:11:05 And even if it were the case, now, if you don't 188 00:11:05 --> 00:11:06 you you're going to die. 189 00:11:06 --> 00:11:09 Well, so what? 190 00:11:09 --> 00:11:12 YOu've got to answer -- I mean is it why you do anything is 191 00:11:12 --> 00:11:15 a question that requires some sort of an answer. 192 00:11:15 --> 00:11:19 And I will give a three- part answer. 193 00:11:19 --> 00:11:25 Part one of the answer will be that you are a slave to, you 194 00:11:25 --> 00:11:28 do things as a slave to the environment. 195 00:11:28 --> 00:11:31 Part two will be that you do things, as a slave, in fact, to 196 00:11:31 --> 00:11:37 your own brain, and part three will be to say well, parts one 197 00:11:37 --> 00:11:39 and two seemed a little simple- minded, we'd better try and get 198 00:11:39 --> 00:11:43 to a somewhat richer explanation that might explain 199 00:11:43 --> 00:11:49 why you're sitting here in a classroom doing this rather 200 00:11:49 --> 00:11:53 complicated activity, since what we'll be talking about is 201 00:11:53 --> 00:11:56 -- oh, one of the things will be talking about is the reason 202 00:11:56 --> 00:12:00 that -- is the obvious fact that I'm a psych professor 203 00:12:00 --> 00:12:02 and not an artist. 204 00:12:02 --> 00:12:06 So you will have to bear with the fact that, for present 205 00:12:06 --> 00:12:13 purposes, that is a cat, and that is a rat. 206 00:12:13 --> 00:12:17 207 00:12:17 --> 00:12:20 You are neither, are the third part of the lecture will be 208 00:12:20 --> 00:12:27 devoted to trying to talk up about the richer set of 209 00:12:27 --> 00:12:29 motivations that you might have, and that even 210 00:12:29 --> 00:12:32 animals might have. 211 00:12:32 --> 00:12:35 Well, a good starting place, even if it's a bad bit of 212 00:12:35 --> 00:12:40 art, would be -- this is an unusually pathetic 213 00:12:40 --> 00:12:42 cat, even for me. 214 00:12:42 --> 00:12:52 Back in the -- shortly before the turn of the last century, 215 00:12:52 --> 00:12:56 Thorndike, Edward Thorndike up at Harvard was doing 216 00:12:56 --> 00:13:00 experiments of the following form: he would take cats, who 217 00:13:00 --> 00:13:06 were hungry cats, and he would throw them in a box that looked 218 00:13:06 --> 00:13:11 sort of like a packing crate kind of thing, you know, slats 219 00:13:11 --> 00:13:17 all the place, and outside of the box is fish, well, bit of 220 00:13:17 --> 00:13:19 fish, but if I drew a bit of fish, you'd never 221 00:13:19 --> 00:13:20 know what it was. 222 00:13:20 --> 00:13:21 This at least looks sort of like a fish. 223 00:13:21 --> 00:13:23 So there's a bit of fish. 224 00:13:23 --> 00:13:24 You got a hungry cat. 225 00:13:24 --> 00:13:25 You got the fish. 226 00:13:25 --> 00:13:28 Cat wants fish. 227 00:13:28 --> 00:13:29 What's the cat going to do? 228 00:13:29 --> 00:13:36 Well, the cat is of bouncing off the walls being annoyed and 229 00:13:36 --> 00:13:42 agitated and the way this box is set up is, well, they're 230 00:13:42 --> 00:13:47 called puzzle boxes, because in effect, er there's a 231 00:13:47 --> 00:13:48 trick to getting out. 232 00:13:48 --> 00:13:53 It might be that there's a lever back here that's attached 233 00:13:53 --> 00:13:58 to some string and pulley arrangement that lifts a gate 234 00:13:58 --> 00:14:03 over here, and if the cat happens to bounce into this 235 00:14:03 --> 00:14:08 lever, the gate goes up, the cat goes out, gets the fish. 236 00:14:08 --> 00:14:11 Great, well it's a little piece of fish, and he's a hungry cat. 237 00:14:11 --> 00:14:14 And what happens to the cat immediately thereafter, is 238 00:14:14 --> 00:14:18 Thorndike grabs the cat again, throws him back in the box. 239 00:14:18 --> 00:14:19 What's the cat do? 240 00:14:19 --> 00:14:26 Well, whatever the cat is doing, what Thorndike is doing 241 00:14:26 --> 00:14:33 is measuring the amount of time that it takes for the cat 242 00:14:33 --> 00:14:36 to get out of the box. 243 00:14:36 --> 00:14:41 As a function of the number of times that the cat has been 244 00:14:41 --> 00:14:42 chucked back in the box. 245 00:14:42 --> 00:14:49 So you've got time as a function of -- we can call them 246 00:14:49 --> 00:14:52 trials, the number of times the cat has been in the box. 247 00:14:52 --> 00:14:54 It initially takes the cat some amount of time. 248 00:14:54 --> 00:14:57 The next time maybe it's a little quicker, and you got 249 00:14:57 --> 00:15:02 some sort of a function that eventually gets to some sort 250 00:15:02 --> 00:15:05 of asymptote where you chuck the cat in the box. 251 00:15:05 --> 00:15:07 The cat looks at you in a disgusted kind of way. 252 00:15:07 --> 00:15:10 Goes over to level, says "plahtttt", eats the 253 00:15:10 --> 00:15:14 fish, says, OK, we gotta do this again, fine. 254 00:15:14 --> 00:15:16 This is a learning curve. 255 00:15:16 --> 00:15:20 In fact, this is the original use of the term learning curve, 256 00:15:20 --> 00:15:22 when you talk about going up the learning curve and 257 00:15:22 --> 00:15:26 stuff like that, you are invoking Thorndike. 258 00:15:26 --> 00:15:31 What is the cat learning? 259 00:15:31 --> 00:15:34 In the 19th century, and even today if you go to, you know, 260 00:15:34 --> 00:15:37 the animal section of Borders or something like that, there 261 00:15:37 --> 00:15:39 are lots of books that will tell you about the, you know, 262 00:15:39 --> 00:15:44 the rich mental life of your cat, and so on. 263 00:15:44 --> 00:15:46 Thorndike wasn't buying it. 264 00:15:46 --> 00:15:54 What Thorndike said was that there are good 265 00:15:54 --> 00:15:56 things in the world. 266 00:15:56 --> 00:15:59 We'll call those reinforcers. 267 00:15:59 --> 00:16:06 268 00:16:06 --> 00:16:08 They come in two forms. 269 00:16:08 --> 00:16:10 There are positive reinforcers. 270 00:16:10 --> 00:16:16 271 00:16:16 --> 00:16:21 Well here, as an example, if you tell a joke and people 272 00:16:21 --> 00:16:24 laugh, that's a positive reinforcer. you did something. 273 00:16:24 --> 00:16:26 Something good happened. 274 00:16:26 --> 00:16:29 There are also negative reinforcers. 275 00:16:29 --> 00:16:33 276 00:16:33 --> 00:16:34 Those are also good things. 277 00:16:34 --> 00:16:38 The jargon IS unfortunate, but a negative reinforcer 278 00:16:38 --> 00:16:39 is a good thing. 279 00:16:39 --> 00:16:42 Focus on the reinforcement part not the negative part. 280 00:16:42 --> 00:16:49 A negative reinforcer is the car alarm is going off, right? 281 00:16:49 --> 00:16:54 You do something that makes that noise stop. 282 00:16:54 --> 00:16:56 Right, that's a good thing. 283 00:16:56 --> 00:16:59 The sensation of something unpleasant, like hunger, 284 00:16:59 --> 00:17:02 for example, is a negative reinforcer. 285 00:17:02 --> 00:17:03 It's also a good thing. 286 00:17:03 --> 00:17:07 A bad thing in this jargon is punishment, is called 287 00:17:07 --> 00:17:09 punishment, right? 288 00:17:09 --> 00:17:11 You tell a joke. 289 00:17:11 --> 00:17:13 The person you're telling the joke to take 290 00:17:13 --> 00:17:15 offense and smacks you. 291 00:17:15 --> 00:17:17 That's punishment. 292 00:17:17 --> 00:17:21 What Thorndike said, what Thorndike formulated, which is 293 00:17:21 --> 00:17:28 undoubtedly on the handout somewhere, is th law of effect. 294 00:17:28 --> 00:17:30 Yes, top of the second page. 295 00:17:30 --> 00:17:33 He proposed what he called the law of effect. 296 00:17:33 --> 00:17:38 And he said that something that's followed by a 297 00:17:38 --> 00:17:42 reinforcer, a behavior that's followed by a reinforcer, is 298 00:17:42 --> 00:17:44 more likely to recur. 299 00:17:44 --> 00:17:45 Take the job example. 300 00:17:45 --> 00:17:49 If you tell a joke and somebody, and people laugh, the 301 00:17:49 --> 00:17:52 next time the opportunity presents itself, you are more 302 00:17:52 --> 00:17:54 likely to tell that joke. 303 00:17:54 --> 00:17:59 The negative law of effect is or is not on the 304 00:17:59 --> 00:18:00 handout somewhere. 305 00:18:00 --> 00:18:02 Well, yes, there it is, a little further down under where 306 00:18:02 --> 00:18:05 it says punishment, the negative law of effect says 307 00:18:05 --> 00:18:07 that you do something, and something bad happens, you're 308 00:18:07 --> 00:18:09 less likely to do it again. 309 00:18:09 --> 00:18:10 You tell a joke. 310 00:18:10 --> 00:18:13 Somebody smacks you, the next time the opportunity presents 311 00:18:13 --> 00:18:17 itself, unless you're a teenage male, odds are that you 312 00:18:17 --> 00:18:20 won't tell that joke again. 313 00:18:20 --> 00:18:24 Well, it is a separate problem. 314 00:18:24 --> 00:18:28 This is the burping problem, right? 315 00:18:28 --> 00:18:34 When you were like 12 maybe, you discovered you could burp 316 00:18:34 --> 00:18:38 the alphabet or something, and your twelve- year- old guy 317 00:18:38 --> 00:18:40 friends thought it was really great. 318 00:18:40 --> 00:18:44 So the behavior got reinforced, and unfortunately it takes a 319 00:18:44 --> 00:18:47 lot of smacks before you unlearn that, but that's 320 00:18:47 --> 00:18:48 actually the next lecture. 321 00:18:48 --> 00:18:50 We'll talk about that next week. 322 00:18:50 --> 00:18:53 323 00:18:53 --> 00:18:57 I'm looking at the handout and realizing that I failed to give 324 00:18:57 --> 00:19:01 you the great bunny example. 325 00:19:01 --> 00:19:04 And you're going to look at your notes later and 326 00:19:04 --> 00:19:06 wonder what this is. 327 00:19:06 --> 00:19:09 But I can use that to illustrate this same point. 328 00:19:09 --> 00:19:10 I have a rabbit. 329 00:19:10 --> 00:19:11 Anybody want a rabbit? 330 00:19:11 --> 00:19:12 We have a rabbit. 331 00:19:12 --> 00:19:13 It's an accident. 332 00:19:13 --> 00:19:14 You can have him. 333 00:19:14 --> 00:19:18 But anyway, this rabbit, when I go down into the kitchen in 334 00:19:18 --> 00:19:20 the morning, goes berserk. 335 00:19:20 --> 00:19:23 He's thumping up and down in his cage. 336 00:19:23 --> 00:19:24 Why is he? 337 00:19:24 --> 00:19:25 Well, what's he doing? 338 00:19:25 --> 00:19:31 Well basically, he's signaling that it's time for breakfast. 339 00:19:31 --> 00:19:32 Not just any breakfast. 340 00:19:32 --> 00:19:35 If you give him rabbit chow, he keeps thumping. 341 00:19:35 --> 00:19:38 He's addicted to Reese's pieces, not Reese's pieces, 342 00:19:38 --> 00:19:40 the Reese's cereal. 343 00:19:40 --> 00:19:43 It's very sad. 344 00:19:43 --> 00:19:46 He's a sugar cereal junkie. 345 00:19:46 --> 00:19:53 And in these terms, what's happened, the way, where his 346 00:19:53 --> 00:19:56 behavior is coming from, what's driving his behavior, is he was 347 00:19:56 --> 00:20:00 making some sort of arbitrary noise at some point when we fed 348 00:20:00 --> 00:20:03 him, and perhaps when we fed him Reese's cereal 349 00:20:03 --> 00:20:05 the first time. 350 00:20:05 --> 00:20:07 It was really good. 351 00:20:07 --> 00:20:09 It was a positive reinforcer. 352 00:20:09 --> 00:20:12 It made more likely the behavior that he had 353 00:20:12 --> 00:20:13 just been doing. 354 00:20:13 --> 00:20:17 So the next time the opportunity presented himself 355 00:20:17 --> 00:20:19 you went thump, thump, thump, being the right time of day 356 00:20:19 --> 00:20:22 anyway he got more Reese's stuff. 357 00:20:22 --> 00:20:29 And now, by this law of effect kind of training, he has 358 00:20:29 --> 00:20:34 learned that if he goes thump, thump, thump, we'll remember 359 00:20:34 --> 00:20:36 that it's time for the sweet cereal. 360 00:20:36 --> 00:20:39 And he gets very disappointed when it turns out that, you 361 00:20:39 --> 00:20:42 know, that the sweet cereal supply has run out and we're 362 00:20:42 --> 00:20:45 trying to feed him like some health food stuff. 363 00:20:45 --> 00:20:48 He's not interested. 364 00:20:48 --> 00:20:52 Carrots are OK, but only barely. 365 00:20:52 --> 00:20:57 So why is it that animals -- well, how many of 366 00:20:57 --> 00:20:59 you have cats and dogs? 367 00:20:59 --> 00:21:02 Cats or dogs, one or the other, you don't have to have both. 368 00:21:02 --> 00:21:04 Almost all of you can probably tell me something about the 369 00:21:04 --> 00:21:08 brilliant, intelligent behavior of this dog that doesn't sound, 370 00:21:08 --> 00:21:11 or cat, that doesn't sound like this sort of accidental 371 00:21:11 --> 00:21:14 learning of an association between a behavior and 372 00:21:14 --> 00:21:15 it's consequences. 373 00:21:15 --> 00:21:18 This sort of association learning, by the way, is what 374 00:21:18 --> 00:21:20 I'll talk about, the rules of it I'll talk about 375 00:21:20 --> 00:21:22 extensively next week. 376 00:21:22 --> 00:21:26 But why is it that we're so convinced that animals have a 377 00:21:26 --> 00:21:28 much richer intellectual life? 378 00:21:28 --> 00:21:30 Well, one possibility is that they do have a richer 379 00:21:30 --> 00:21:32 intellectual life than this. 380 00:21:32 --> 00:21:36 The other, the one that Thorndike thought he was 381 00:21:36 --> 00:21:40 seeing, was what really boils down to selective reporting. 382 00:21:40 --> 00:21:42 Did I put the whole quote on the handout? 383 00:21:42 --> 00:21:44 No. 384 00:21:44 --> 00:21:50 What Thorndike said is dogs get lost hundreds of times, and 385 00:21:50 --> 00:21:54 nobody ever notices it or sends an account to a scientific 386 00:21:54 --> 00:21:59 magazine, but let one dog find his way from Brooklyn to 387 00:21:59 --> 00:22:02 Yonkers, and that fact immediately becomes a 388 00:22:02 --> 00:22:04 circulating anecdote. 389 00:22:04 --> 00:22:10 Thousands of cats, he says, sit on thousands of occasions 390 00:22:10 --> 00:22:14 helplessly yowling, and nobody ever writes to his friend, 391 00:22:14 --> 00:22:16 the professor, about it. 392 00:22:16 --> 00:22:23 But let one cat claw at the knob, seemingly in, supposedly 393 00:22:23 --> 00:22:28 as a signal to be let out, and straight away, that cat becomes 394 00:22:28 --> 00:22:30 the representative of the cat mind. 395 00:22:30 --> 00:22:34 What Thorndike thought was, that you are, well at least the 396 00:22:34 --> 00:22:38 cat, and by extension, you are, a slave to your environment. 397 00:22:38 --> 00:22:42 The contingencies in your environment shape what you do. 398 00:22:42 --> 00:22:46 If the environment rewards you for pushing this lever, 399 00:22:46 --> 00:22:48 you'll push this lever. 400 00:22:48 --> 00:22:53 And the cleverness, and the content of that, the seeming 401 00:22:53 --> 00:22:57 content of that, is imposed from the outside. 402 00:22:57 --> 00:22:57 It's not there. 403 00:22:57 --> 00:22:59 It's not necessary. 404 00:22:59 --> 00:23:02 You can explain it all, you can explain why you do things 405 00:23:02 --> 00:23:08 purely in terms of these, of this law of effect. 406 00:23:08 --> 00:23:09 Suitably elaborated. 407 00:23:09 --> 00:23:13 And as I say, the suitable elaboration on that will 408 00:23:13 --> 00:23:19 come, will come next week. 409 00:23:19 --> 00:23:21 The elaboration, by the way, is known as behaviorism and the 410 00:23:21 --> 00:23:24 school of scientific, of psychological thought, that 411 00:23:24 --> 00:23:33 says that the explanation for your behavior can be found in 412 00:23:33 --> 00:23:40 the contingencies that relate your actions to their 413 00:23:40 --> 00:23:43 consequences in the world and that relates, the relationships 414 00:23:43 --> 00:23:47 between stimulae in the world. 415 00:23:47 --> 00:23:51 That gets you some distance, but what is it that actually 416 00:23:51 --> 00:23:54 makes something reinforcing? 417 00:23:54 --> 00:23:58 Why should something be reinforcing at all? 418 00:23:58 --> 00:24:03 What is it about say food that, you know, why does the cat 419 00:24:03 --> 00:24:08 care that he gets out and satisfies his hunger? 420 00:24:08 --> 00:24:14 For that, you want to switch to the second form of slavery, 421 00:24:14 --> 00:24:20 which is this notion that you are slave to your own 422 00:24:20 --> 00:24:21 brain in a sense. 423 00:24:21 --> 00:24:28 And the emblematic experiment for that is done some 50 years 424 00:24:28 --> 00:24:31 after Thorndike is working with his puzzle box. 425 00:24:31 --> 00:24:35 And that comes from an experiment done by [? Olton ?] 426 00:24:35 --> 00:24:35 [? Milner ?]. 427 00:24:35 --> 00:24:38 It actually started as a mistake done by [? Olton ?] 428 00:24:38 --> 00:24:38 [? Milner ?]. 429 00:24:38 --> 00:24:42 Here's what they were doing. 430 00:24:42 --> 00:24:45 They were sticking electrodes it's into the brain of rats, 431 00:24:45 --> 00:24:52 into the brains of rats, down into the brain stem, because 432 00:24:52 --> 00:24:55 what they wanted to do was to study arousal. 433 00:24:55 --> 00:24:59 Centers down in the brain stem, I mentioned last time, are 434 00:24:59 --> 00:25:03 intimately involved in things like sleep and wake, so a 435 00:25:03 --> 00:25:04 general level of arousal. 436 00:25:04 --> 00:25:08 How do you know if a rat is aroused or not? 437 00:25:08 --> 00:25:12 Well, one of the ways to measure arousal in a rat is 438 00:25:12 --> 00:25:14 just to look at the amount of activity that that 439 00:25:14 --> 00:25:16 rat is emitting. 440 00:25:16 --> 00:25:19 A rat that's just sort of sitting there is not very 441 00:25:19 --> 00:25:20 aroused, and a rat that's running around is 442 00:25:20 --> 00:25:22 presumably aroused. 443 00:25:22 --> 00:25:24 Great, so they're going to stick an electrode into a rat's 444 00:25:24 --> 00:25:28 brain and look at general levels of activity. 445 00:25:28 --> 00:25:33 There's a problem that requires a control experiment first. 446 00:25:33 --> 00:25:37 What other than sort of generalized arousal might 447 00:25:37 --> 00:25:41 get a rat to run around, would you think? 448 00:25:41 --> 00:25:42 AUDIENCE: [UNINTELLIGIBLE] 449 00:25:42 --> 00:25:44 PROFESSOR: Sticking an electrode into their brain. 450 00:25:44 --> 00:25:49 Yeah, well, why might sticking an elecrode in their brain 451 00:25:49 --> 00:25:50 make them run around? 452 00:25:50 --> 00:25:54 AUDIENCE: Pain. 453 00:25:54 --> 00:25:55 PROFESSOR: Pain, it might hurt, right? 454 00:25:55 --> 00:26:03 You know, so suppose all that happens when you turn on the 455 00:26:03 --> 00:26:05 electricity, you know, to stimulate the brain of 456 00:26:05 --> 00:26:07 the rat is it hurts. 457 00:26:07 --> 00:26:10 The rat is going to run around, but you wouldn't want to argue 458 00:26:10 --> 00:26:14 that this is a center for generalized arousal. 459 00:26:14 --> 00:26:16 Plus, you might not really want to be, you know, 460 00:26:16 --> 00:26:17 hurting your poor rat. 461 00:26:17 --> 00:26:20 So anyway, here's the experiment that they did. 462 00:26:20 --> 00:26:25 What they did was they watched the electrodes in the rat, and 463 00:26:25 --> 00:26:29 they're looking at the rat, and they only turn the electricity 464 00:26:29 --> 00:26:33 on when the rat is over in this part of the cage. 465 00:26:33 --> 00:26:35 So, turn on the electricity. 466 00:26:35 --> 00:26:39 If it hurts, what does the rat do? 467 00:26:39 --> 00:26:41 AUDIENCE: Runs around. 468 00:26:41 --> 00:26:41 PROFESSOR: Runs around, but... 469 00:26:41 --> 00:26:42 AUDIENCE: [UNINTELLIGIBLE]. 470 00:26:42 --> 00:26:45 PROFESSOR: To the other, but hey, ooh, it stopped. 471 00:26:45 --> 00:26:50 Now wander back over here, oh, no, OK, right? 472 00:26:50 --> 00:26:52 Everybody knows rats learn this. 473 00:26:52 --> 00:26:55 They knew that nobody had done this with 474 00:26:55 --> 00:26:57 stimulation of the brain. 475 00:26:57 --> 00:27:02 This is so-called aversive learning. 476 00:27:02 --> 00:27:04 One of the typical ways of doing it is you electrify the 477 00:27:04 --> 00:27:07 floor of the cage, right? 478 00:27:07 --> 00:27:11 So, the rat goes over here, discovers that when he puts his 479 00:27:11 --> 00:27:14 little rat toes on the cage floor over here, there's 480 00:27:14 --> 00:27:18 electric current running through it and phew, 481 00:27:18 --> 00:27:19 he's over here. 482 00:27:19 --> 00:27:22 OK, so that's what they did, and so the rat goes over here, 483 00:27:22 --> 00:27:28 and on comes the juice for a little bit, and the rat doesn't 484 00:27:28 --> 00:27:30 go anywhere, and then the juice goes off, and the rat is 485 00:27:30 --> 00:27:34 wandering around and then the rat comes back over here, juice 486 00:27:34 --> 00:27:36 comes on for a little bit. 487 00:27:36 --> 00:27:39 Rat doesn't go anywhere. 488 00:27:39 --> 00:27:42 In fact, the rat comes back over here. 489 00:27:42 --> 00:27:46 The rat is sort of hanging around over here, yeah, 490 00:27:46 --> 00:27:48 let's do that again. 491 00:27:48 --> 00:27:57 Turns out that the rat was behaving as though the 492 00:27:57 --> 00:27:59 stimulation was reinforcing. 493 00:27:59 --> 00:28:05 We could say as though he wanted to be stimulated, but 494 00:28:05 --> 00:28:08 it's a little dicey to talk about what a rat wants 495 00:28:08 --> 00:28:09 or doesn't want. 496 00:28:09 --> 00:28:10 So you can use this more neutral language 497 00:28:10 --> 00:28:11 of reinforcement. 498 00:28:11 --> 00:28:16 The rat was behaving as though stimulation of the 499 00:28:16 --> 00:28:17 brain was reinforcing. 500 00:28:17 --> 00:28:19 This was a surprise to [? Olton ?] 501 00:28:19 --> 00:28:20 [? Milner. ?] 502 00:28:20 --> 00:28:24 The next surprise came when they actually looked at where 503 00:28:24 --> 00:28:28 the electrode had gone in this particular rat's brain. 504 00:28:28 --> 00:28:29 That's the mistake part. 505 00:28:29 --> 00:28:34 It turns out the electrode had bent, and instead of being 506 00:28:34 --> 00:28:38 where they wanted it in the brain stem, it was in the chunk 507 00:28:38 --> 00:28:40 of brain known as the lateral hypothalamus. 508 00:28:40 --> 00:28:43 At least we think it was in the lateral hypothalamus. 509 00:28:43 --> 00:28:46 Don't actually know, because not only did the electrode 510 00:28:46 --> 00:28:50 bend, but then they lost the brain. 511 00:28:50 --> 00:28:54 Subsequently, they did very well for all the 512 00:28:54 --> 00:28:55 mistakes they made here. 513 00:28:55 --> 00:28:56 Hypothalamus. 514 00:28:56 --> 00:29:00 515 00:29:00 --> 00:29:07 So, what they did that was to deliberately stick electrodes 516 00:29:07 --> 00:29:11 into the hypothalamus and to set the experiment up in a more 517 00:29:11 --> 00:29:15 formal fashion, beautifully illustrated here by my rat, 518 00:29:15 --> 00:29:17 who's got an electrode in his brain, and that's a 519 00:29:17 --> 00:29:19 battery up there. 520 00:29:19 --> 00:29:20 And that's a lever. 521 00:29:20 --> 00:29:24 Now the rat can go off and self- stimulate. 522 00:29:24 --> 00:29:29 He can go and choose, if he pushes on this lever, he 523 00:29:29 --> 00:29:33 gets a little pulse of electricity to his brain. 524 00:29:33 --> 00:29:34 And what does he do? 525 00:29:34 --> 00:29:38 Indeed, rats with electrodes implanted in the right bits of 526 00:29:38 --> 00:29:41 the lateral hypothalamus will sit there and work for brain 527 00:29:41 --> 00:29:45 stimulation, the way another rat might work for rat pellets 528 00:29:45 --> 00:29:49 water if it's thirsty or something like that. 529 00:29:49 --> 00:29:51 And they'll work hard. 530 00:29:51 --> 00:29:56 The most dramatic version I can recall reading is a rat that 531 00:29:56 --> 00:30:03 will work bar pressing 7,000 times an hour, I think, for 532 00:30:03 --> 00:30:08 to keep the brain stimulated there. 533 00:30:08 --> 00:30:11 So this is apparently good stuff. 534 00:30:11 --> 00:30:12 Not everything there is good stuff. 535 00:30:12 --> 00:30:16 There are chunks of brain where the rat will work actively 536 00:30:16 --> 00:30:18 to turn off the stimulation. 537 00:30:18 --> 00:30:22 So again, so turning on the stimulation would be a 538 00:30:22 --> 00:30:23 positive reinforcer. 539 00:30:23 --> 00:30:26 Turning off an aversive stimulation, whether it's 540 00:30:26 --> 00:30:29 electricity to your feet or electricity to the wrong 541 00:30:29 --> 00:30:33 part of your brain, that's a negative reinforcer. 542 00:30:33 --> 00:30:35 So you know, there's current. 543 00:30:35 --> 00:30:38 If you push the button the current stops. 544 00:30:38 --> 00:30:42 That's good from the rat's point of view. 545 00:30:42 --> 00:30:45 In various surveys of rat brain, it turns out there 546 00:30:45 --> 00:30:48 are more positive locations than negative locations. 547 00:30:48 --> 00:30:49 I don't know. 548 00:30:49 --> 00:30:51 You know, we don't know if that's true of humans, and we 549 00:30:51 --> 00:30:55 don't know if that means anything -- actually the study, 550 00:30:55 --> 00:31:00 the study that I noticed this morning that I was thinking of 551 00:31:00 --> 00:31:03 here says that they're 60 percent, in this one study, 60 552 00:31:03 --> 00:31:07 percent neutral locations, 30 percent rewarding 553 00:31:07 --> 00:31:10 locations, and 5 percent aversive locations. 554 00:31:10 --> 00:31:13 Now the mathematically sophisticated among you 555 00:31:13 --> 00:31:16 will notice that adds up to 95 percent. 556 00:31:16 --> 00:31:18 And neutral rewarding and aversive would kind of seem to 557 00:31:18 --> 00:31:21 cover all the possibilities here, so I have no idea what 558 00:31:21 --> 00:31:23 the other 5 percent of neurons we're doing. 559 00:31:23 --> 00:31:26 That seems a lot for rounding error or something. 560 00:31:26 --> 00:31:32 Anyway more pleasant locations then unpleasant locations. 561 00:31:32 --> 00:31:38 Now, around this time, somebody who is a science fiction buff 562 00:31:38 --> 00:31:42 should say, I've heard this before, it shows up in one of 563 00:31:42 --> 00:31:47 several classic science fiction stories. 564 00:31:47 --> 00:31:49 The world is full of science fiction stories written by 565 00:31:49 --> 00:31:53 people just like you, which is to say people who heard an 566 00:31:53 --> 00:31:57 introductory psych lecture and thought I can make a 567 00:31:57 --> 00:31:58 story out of this. 568 00:31:58 --> 00:32:02 Memento, is perhaps the most recent movie example of that. 569 00:32:02 --> 00:32:06 We'll get to that lecture later on in the term. 570 00:32:06 --> 00:32:10 Anybody familiar with the sci fi story that's 571 00:32:10 --> 00:32:13 related to the rats here? 572 00:32:13 --> 00:32:15 Any of the various sci fi stories? 573 00:32:15 --> 00:32:16 AUDIENCE: Mrs. Frisbee? 574 00:32:16 --> 00:32:16 Is 575 00:32:16 --> 00:32:17 PROFESSOR: Oh, no. 576 00:32:17 --> 00:32:20 Mrs. Frisbee and the rats of NIMH. 577 00:32:20 --> 00:32:26 What's -- no, apart from the fact that NIMH is short for the 578 00:32:26 --> 00:32:31 National Institute of Mental Health and they don't 579 00:32:31 --> 00:32:33 much care for that. 580 00:32:33 --> 00:32:36 But what are the rats of NIMH doing? 581 00:32:36 --> 00:32:39 Oh no, they're busy taking drugs and getting smart, right? 582 00:32:39 --> 00:32:41 Na, Na. they're not sitting there stimulating their 583 00:32:41 --> 00:32:44 little selves, yeah. 584 00:32:44 --> 00:32:44 AUDIENCE: Terminal Man? 585 00:32:44 --> 00:32:46 PROFESSOR: Yeah, Terminal Man, that sounds right. 586 00:32:46 --> 00:32:47 What's Terminal Man's issue? 587 00:32:47 --> 00:32:54 AUDIENCE: He has epileptic fits, [UNINTELLIGIBLE]. 588 00:32:54 --> 00:32:55 PROFESSOR: And it does give him pleasure, yes. 589 00:32:55 --> 00:32:56 OK that's -- yeah. 590 00:32:56 --> 00:33:00 AUDIENCE: Flowers for Algernon? 591 00:33:00 --> 00:33:01 PROFESSOR: Flowers for Algernon? 592 00:33:01 --> 00:33:03 No, what's he doing? 593 00:33:03 --> 00:33:04 Is he being stimulated? 594 00:33:04 --> 00:33:08 AUDIENCE: [UNINTELLIGIBLE] 595 00:33:08 --> 00:33:12 PROFESSOR: Oh yeah, but he just becomes a super smart rat 596 00:33:12 --> 00:33:15 like the rats of NIMH one. 597 00:33:15 --> 00:33:18 He's got a different -- we don't know how to make super 598 00:33:18 --> 00:33:21 smart rats, we just know how to make rats who will work 599 00:33:21 --> 00:33:23 hard on pushing levers. 600 00:33:23 --> 00:33:27 The Terminal Man one is one of the sci fi examples 601 00:33:27 --> 00:33:28 that I know about. 602 00:33:28 --> 00:33:31 Anyway, look, the critical issue that gets people writing 603 00:33:31 --> 00:33:34 science fiction stories is, suppose we did this to a human, 604 00:33:34 --> 00:33:39 would that human, could you killed somebody by hooking them 605 00:33:39 --> 00:33:44 up to self- stimulate their pleasure center, and they 606 00:33:44 --> 00:33:45 would kill themselves. 607 00:33:45 --> 00:33:47 How would they kill themselves? 608 00:33:47 --> 00:33:49 By, you know, sitting there, oh, oh, oh, and 609 00:33:49 --> 00:33:53 forgetting to eat, right? 610 00:33:53 --> 00:33:54 Well nobody's ever done this in humans of course. 611 00:33:54 --> 00:33:58 It's been done in rats. 612 00:33:58 --> 00:34:09 And if you put a lever a lever that gives food next to a lever 613 00:34:09 --> 00:34:14 the gives stimulation in a good spot in the rat's brain, the 614 00:34:14 --> 00:34:21 rat will sit there and work away on the self- 615 00:34:21 --> 00:34:23 stimulation lever. 616 00:34:23 --> 00:34:28 And at least in some of these studies, well, every now and 617 00:34:28 --> 00:34:34 then, sort of, say oh, get a little food, OK, back over 618 00:34:34 --> 00:34:35 here to the video game stuff. 619 00:34:35 --> 00:34:38 This is really good. 620 00:34:38 --> 00:34:40 This is what your parents thought you were doing, right? 621 00:34:40 --> 00:34:42 Yeah, come on down and eat dinner. 622 00:34:42 --> 00:34:45 Oh, Mom, I can't put it on pause, yeah. 623 00:34:45 --> 00:34:53 Anyway, the -- would an animal actually kill itself? 624 00:34:53 --> 00:34:58 Gleitman says that hungry rats will opt for self- stimulation 625 00:34:58 --> 00:35:00 even though it literally brings starvation. 626 00:35:00 --> 00:35:06 And then he sites an article that I went back and read, and 627 00:35:06 --> 00:35:09 the rats in that study didn't starve themselves to death, 628 00:35:09 --> 00:35:12 because the researchers wouldn't do it, presumably 629 00:35:12 --> 00:35:15 because it seemed unethical to actually let a rat 630 00:35:15 --> 00:35:18 starve itself to death. 631 00:35:18 --> 00:35:21 But they will certainly reduce, you know, they'll certainly get 632 00:35:21 --> 00:35:26 themselves pretty hungry while amusing themselves with the, 633 00:35:26 --> 00:35:27 by stimulating their brain. 634 00:35:27 --> 00:35:28 There was a hand up, oh there still is a hand 635 00:35:28 --> 00:35:29 up there, look at that. 636 00:35:29 --> 00:35:37 AUDIENCE: [UNINTELLIGIBLE]. 637 00:35:37 --> 00:35:43 PROFESSOR: I don't know that the truth or falsity -- so the 638 00:35:43 --> 00:35:47 story is a guy played video games for, what was it, 74 639 00:35:47 --> 00:35:50 straight hours, 74 straight hours in Korea, 640 00:35:50 --> 00:35:52 and then he died. 641 00:35:52 --> 00:35:58 Actually the Korea part is good here, because I have no 642 00:35:58 --> 00:36:00 idea whether this is true one way or the other. 643 00:36:00 --> 00:36:07 It has all the Hallmarks of a so- called urban legend. 644 00:36:07 --> 00:36:11 It has a grain of plausability, and is just sort of one step 645 00:36:11 --> 00:36:13 removed from checkability. 646 00:36:13 --> 00:36:18 It's like the Kentucky Fried breaded rat, right? 647 00:36:18 --> 00:36:22 Everybody knows somebody else who knows that their cousin 648 00:36:22 --> 00:36:25 got a breaded rat once. 649 00:36:25 --> 00:36:27 There are whole books of these things, they're great. 650 00:36:27 --> 00:36:30 I don't know, maybe somebody managed to play video 651 00:36:30 --> 00:36:30 games until they died. 652 00:36:30 --> 00:36:34 People do all sorts of stupid things. 653 00:36:34 --> 00:36:38 I don't recommend trying this yourself. 654 00:36:38 --> 00:36:44 In any case, rats will work very hard in order to stimulate 655 00:36:44 --> 00:36:45 different parts of their brain. 656 00:36:45 --> 00:36:50 What is it that they're working for? 657 00:36:50 --> 00:36:53 The evidence suggests that they're not just working for 658 00:36:53 --> 00:36:57 some sort of disembodied pleasure, but that they're 659 00:36:57 --> 00:37:01 working for the reward associated with one or the 660 00:37:01 --> 00:37:09 other of sort of basic hard- wired, innate reward systems, 661 00:37:09 --> 00:37:13 that you come with, but that the rat comes with too. 662 00:37:13 --> 00:37:20 The reason that in this aspect of the slavery story, that 663 00:37:20 --> 00:37:27 you'll work to get the fish if you're the cat is that you came 664 00:37:27 --> 00:37:32 predisposed to think that hunger is bad and food is good. 665 00:37:32 --> 00:37:34 This, yeah, look, it doesn't take very sophisticated 666 00:37:34 --> 00:37:36 evolutionary psychological theory to think this 667 00:37:36 --> 00:37:37 might be a good idea. 668 00:37:37 --> 00:37:41 Organisms that went into the world thinking that hunger is 669 00:37:41 --> 00:37:45 good and food is bad had many fewer progeny than the ones 670 00:37:45 --> 00:37:48 who thought that hunger was bad and food was good. 671 00:37:48 --> 00:37:53 So it's not that surprising that you've got circuitry that 672 00:37:53 --> 00:37:57 says if you're hungry you want to go and eat something. 673 00:37:57 --> 00:38:01 And the centers that are being stimulated are in chunks of 674 00:38:01 --> 00:38:05 brain that if you mess with them, mess with the rat's 675 00:38:05 --> 00:38:08 ability to regulate its eating. 676 00:38:08 --> 00:38:11 So there's a wonderful picture in Gleitman of a rat with a 677 00:38:11 --> 00:38:16 hypothalamic lesion, a lesions in this sort of chunk of brain. 678 00:38:16 --> 00:38:18 The specific lesion in this particular rat is in a chunk 679 00:38:18 --> 00:38:20 of brains that seems to be important in telling 680 00:38:20 --> 00:38:21 you when you're full. 681 00:38:21 --> 00:38:23 So this rat never knows that he's full. 682 00:38:23 --> 00:38:25 With the result, he just keeps eating. 683 00:38:25 --> 00:38:30 And so there's this picture in chapter three of a rat on a -- 684 00:38:30 --> 00:38:33 some of you may already have seen it, of a rat on one 685 00:38:33 --> 00:38:35 of those diets scales. 686 00:38:35 --> 00:38:37 You know, and he looks like a fury football. 687 00:38:37 --> 00:38:39 He's just sort of overflowing. 688 00:38:39 --> 00:38:43 that's And that's because he's got a specific lesion in this 689 00:38:43 --> 00:38:45 little specific chunk of brain. 690 00:38:45 --> 00:38:47 How do we know that's what's going on here? 691 00:38:47 --> 00:38:51 Well, you got a rat who's working a way to be stimulated 692 00:38:51 --> 00:38:53 in this little particular chunk of brain. 693 00:38:53 --> 00:38:58 And if he, so let's take this little chunk of brain, if he's 694 00:38:58 --> 00:39:01 a full rat, if you feed him up, he doesn't work as hard. 695 00:39:01 --> 00:39:03 It's just not as interesting. 696 00:39:03 --> 00:39:08 You know this, in your own -- so, you like M&Ms let's say. 697 00:39:08 --> 00:39:11 You're willing to put, you know, you're willing 698 00:39:11 --> 00:39:13 to push the lever to get the M&Ms, right? 699 00:39:13 --> 00:39:15 You're willing to put the quarters in the machine. 700 00:39:15 --> 00:39:17 Would you do that forever? 701 00:39:17 --> 00:39:20 No, because eventually you get full and the M&Ms 702 00:39:20 --> 00:39:22 kind of look disgusting. 703 00:39:22 --> 00:39:25 So the same thing happens here. 704 00:39:25 --> 00:39:32 So the pleasure that the rat is getting is modulated by 705 00:39:32 --> 00:39:36 satisfying, you know, the thing about direct electrical 706 00:39:36 --> 00:39:39 stimulation is it gives the sensation of the satisfaction 707 00:39:39 --> 00:39:41 without actually satisfying anything. 708 00:39:41 --> 00:39:44 So, if you're getting the oh, the M&M is good thing without 709 00:39:44 --> 00:39:47 getting the M&M, you can sit there, oh the M&M is good 710 00:39:47 --> 00:39:50 forever and ever, and keep working on it. 711 00:39:50 --> 00:39:52 Okay, so that's this little chunk of brain. 712 00:39:52 --> 00:39:54 You go over to this other chunk of brain where the rat will 713 00:39:54 --> 00:39:59 also work hard, and that rat doesn't care if he's full, 714 00:39:59 --> 00:40:03 that rat cares whether he's mated recently. 715 00:40:03 --> 00:40:07 So you know, this one is part, you know, this little chunk of 716 00:40:07 --> 00:40:12 brain is presumably related to the reward systems having 717 00:40:12 --> 00:40:14 to do with sex and mating. 718 00:40:14 --> 00:40:17 Again, it doesn't take an evolutionary psych genius to 719 00:40:17 --> 00:40:22 figure out that this would be sensible stuff for a 720 00:40:22 --> 00:40:25 brain to come with. 721 00:40:25 --> 00:40:30 Organisms that didn't find mating rewarding didn't 722 00:40:30 --> 00:40:31 leave many offspring. 723 00:40:31 --> 00:40:34 Yeah, just didn't work out that well for them. 724 00:40:34 --> 00:40:36 And so, you know, there's another reward system. 725 00:40:36 --> 00:40:42 Similarly, for thirst there are separate reward systems. 726 00:40:42 --> 00:40:48 OK, so, in some sense you end up doing stuff in order 727 00:40:48 --> 00:40:51 to light up little pieces of brain or to turn off 728 00:40:51 --> 00:40:52 little pieces of brain. 729 00:40:52 --> 00:40:58 That's the sense in which you are a slave to your brain. 730 00:40:58 --> 00:41:03 Now, you, know that only gets you so far, because 731 00:41:03 --> 00:41:04 that's fairly simple. 732 00:41:04 --> 00:41:08 You know, eat food, little hunk of brain says you're happy. 733 00:41:08 --> 00:41:14 Your behavior is somewhat more complicated than that. 734 00:41:14 --> 00:41:17 How do we get to that more complicated behavior? 735 00:41:17 --> 00:41:19 Well, let's stick with the M&M example. 736 00:41:19 --> 00:41:22 How did you get to the M&Ms? 737 00:41:22 --> 00:41:26 Well, you got to go down to the vending machine 738 00:41:26 --> 00:41:27 and put the money in. 739 00:41:27 --> 00:41:29 And how do you learn to do that? 740 00:41:29 --> 00:41:33 Well, maybe you learn to do that by a chain of associations 741 00:41:33 --> 00:41:34 back to the M&Ms. 742 00:41:34 --> 00:41:37 M&Ms, oh, they're good. 743 00:41:37 --> 00:41:40 Getting M&Ms becomes good in its own right. 744 00:41:40 --> 00:41:44 Somebody gives me M&Ms, that becomes rewarding by 745 00:41:44 --> 00:41:47 association, with the fact that I will now get to eat the M&Ms. 746 00:41:47 --> 00:41:51 This machine will give me M&Ms, but only if I give it quarters. 747 00:41:51 --> 00:41:53 So, I learn to give it quarters. 748 00:41:53 --> 00:41:54 That's an interesting ring. 749 00:41:54 --> 00:41:56 It sounded like a regular old phone. 750 00:41:56 --> 00:41:59 751 00:41:59 --> 00:42:00 Put them on vibrate. 752 00:42:00 --> 00:42:03 That's what I do, because let's see, well, yeah, it's just 753 00:42:03 --> 00:42:04 about the right time. 754 00:42:04 --> 00:42:07 I should be vibrating any time, woops, not that one. 755 00:42:07 --> 00:42:14 My tenth grader tends to phone in after school which is great, 756 00:42:14 --> 00:42:16 the only thing is that after school two days a week turns 757 00:42:16 --> 00:42:22 out to be here, and it's not a good time to take a call. 758 00:42:22 --> 00:42:26 Anyway so ah well, so the tenth grader, he likes M&Ms. 759 00:42:26 --> 00:42:28 He needs quarters. 760 00:42:28 --> 00:42:33 So, he's got to emit behavior that I like so I'll give 761 00:42:33 --> 00:42:35 him quarters right? 762 00:42:35 --> 00:42:38 And so you can see how you could build back from a primary 763 00:42:38 --> 00:42:44 sort of reinforcer, like food is good to something much more 764 00:42:44 --> 00:42:48 remote like cleaning my room is good. 765 00:42:48 --> 00:42:51 Why is cleaning my room -- if I clean my room, 766 00:42:51 --> 00:42:52 daddy gives me quarters. 767 00:42:52 --> 00:42:54 If daddy give me quarters, me I take quarters. 768 00:42:54 --> 00:42:55 I put them in machine. 769 00:42:55 --> 00:42:58 Machine gives me M&Ms and all is good. 770 00:42:58 --> 00:43:01 771 00:43:01 --> 00:43:06 That's OK, but it probably doesn't do quite well. 772 00:43:06 --> 00:43:11 The brain suggests to us that that isn't quite enough, for 773 00:43:11 --> 00:43:15 organizing even the feeding behavior of a complex 774 00:43:15 --> 00:43:17 organism like us. 775 00:43:17 --> 00:43:22 Suppose that you are doing -- that what gets you to do your 776 00:43:22 --> 00:43:27 complicated sort of behavior around feeding is the fact that 777 00:43:27 --> 00:43:29 you're hungry -- oh, chapter three will tell you all about 778 00:43:29 --> 00:43:32 how you know that you're hungry. 779 00:43:32 --> 00:43:34 It's lovely sort of engineering work. 780 00:43:34 --> 00:43:38 You've got little detectors, receptor is in the blood. 781 00:43:38 --> 00:43:40 They're doing things like keeping track of 782 00:43:40 --> 00:43:41 blood sugar levels. 783 00:43:41 --> 00:43:44 When those levels drop, chunks of brain become active. 784 00:43:44 --> 00:43:48 Activity there is apparently aversive, probably 785 00:43:48 --> 00:43:52 corresponding to what you and I think is hunger. 786 00:43:52 --> 00:43:54 When you get sugar in, activity there drops. 787 00:43:54 --> 00:43:57 Lovely, beautiful sort of control systems. 788 00:43:57 --> 00:44:00 Stuff worked out in great detail and discussed in 789 00:44:00 --> 00:44:07 considerabe detail in chapter three, but suppose you're not 790 00:44:07 --> 00:44:10 living in your food, right? 791 00:44:10 --> 00:44:14 Suppose you're, well suppose you're like out on the plains 792 00:44:14 --> 00:44:19 of Africa somewhere, and the M&Ms aren't just sitting over 793 00:44:19 --> 00:44:20 there in the vending machine. 794 00:44:20 --> 00:44:22 They're running around, and you're going to have to 795 00:44:22 --> 00:44:27 hunt them down, right? 796 00:44:27 --> 00:44:32 If you are sitting around until the blood sugar level gets low 797 00:44:32 --> 00:44:35 enough for unpleasant things to happen in these hard-wired 798 00:44:35 --> 00:44:41 chunks of brain, to make you think, OK, all right, I'll 799 00:44:41 --> 00:44:44 remember this, M&Ms or wildebeest s, whichever 800 00:44:44 --> 00:44:46 it was, they're good. 801 00:44:46 --> 00:44:48 I can eat them. 802 00:44:48 --> 00:44:51 To get to wildebeest , I got to go clean my room -- anyway, 803 00:44:51 --> 00:44:53 there's some complicated thing that you gotta do. 804 00:44:53 --> 00:44:58 But if you wait long enough before starting, you may not 805 00:44:58 --> 00:45:01 get it, the job done in time, right? 806 00:45:01 --> 00:45:04 It's going to take you a while to hunt down the wildebeest . 807 00:45:04 --> 00:45:08 If you wait till the gas tank is almost empty, yeah you may 808 00:45:08 --> 00:45:13 find yourself flat out on the plains with, you know, no food. 809 00:45:13 --> 00:45:19 So it would be useful if something got you up and 810 00:45:19 --> 00:45:25 mobilized for activity before you were actually hungry, 811 00:45:25 --> 00:45:28 before you actually were in some sort of desperate need. 812 00:45:28 --> 00:45:34 And the distinction that gets made, and I trust is bolded at 813 00:45:34 --> 00:45:40 the, yes, it's down there at the bottom of page 2, is 814 00:45:40 --> 00:45:45 the distinction between consummatory and appetitive 815 00:45:45 --> 00:45:48 behaviors, or consummatory and appetitive pet motivations. 816 00:45:48 --> 00:45:51 consummatory ones, are the ones we've been talking about so 817 00:45:51 --> 00:45:53 far, eating M&Ms, that's good. 818 00:45:53 --> 00:45:59 Appetitive ones are ones where the act of looking, if you'd 819 00:45:59 --> 00:46:03 like, or getting yourself in a position to consume 820 00:46:03 --> 00:46:04 is itself rewarding. 821 00:46:04 --> 00:46:08 In that case of food, that might be sort of the thrill 822 00:46:08 --> 00:46:11 of the hunt kind of thing. 823 00:46:11 --> 00:46:14 Think about cat, right, your cat that likes to jump 824 00:46:14 --> 00:46:15 on anything that moves. 825 00:46:15 --> 00:46:16 Why is that? 826 00:46:16 --> 00:46:22 It's because the cat is hard wired to like hunting stuff. 827 00:46:22 --> 00:46:25 It's just fun to grab stuff and kill it. 828 00:46:25 --> 00:46:31 Now that's a useful thing to do if you are a cat-like animal 829 00:46:31 --> 00:46:33 because then there's going to be something around to eat when 830 00:46:33 --> 00:46:36 those blood sugar levels drop and you need to, you know, chew 831 00:46:36 --> 00:46:37 on a wildebeest for a while. 832 00:46:37 --> 00:46:41 And it's pretty clear that we have similar, actually, 833 00:46:41 --> 00:46:44 it's pretty clear that in yesterday's political news that 834 00:46:44 --> 00:46:53 we have similar sorts of circuitry in ourselves. 835 00:46:53 --> 00:46:58 Yesterday the assault rifle, the assault weapon ban expired. 836 00:46:58 --> 00:47:01 Bush spent a lot of time not talking about it. 837 00:47:01 --> 00:47:03 Kerry spent a lot of times saying I'm a hunter. 838 00:47:03 --> 00:47:04 I love to hunt. 839 00:47:04 --> 00:47:07 I love to jump on moving things and stuff like that, but I've 840 00:47:07 --> 00:47:08 never done it with an assault weapon. 841 00:47:08 --> 00:47:13 You don't need to use an -- he was on the -- but he was very 842 00:47:13 --> 00:47:17 big on pointing out that he loves to hunt, because 843 00:47:17 --> 00:47:19 apparently there's lots of people who love to hunt and go 844 00:47:19 --> 00:47:24 out and you know, shoot things and sometimes eat things. 845 00:47:24 --> 00:47:29 This is presumably related to, this is presumably a form of 846 00:47:29 --> 00:47:32 appetitive behavior in humans. 847 00:47:32 --> 00:47:34 If you don't happen to love to hunt it doesn't mean 848 00:47:34 --> 00:47:37 that you're missing a piece of your brain. 849 00:47:37 --> 00:47:44 Another realm where appetitive behavior is important is in 850 00:47:44 --> 00:47:48 the sex and romance department, right? 851 00:47:48 --> 00:47:56 If it were not the case that the act of looking up for a 852 00:47:56 --> 00:48:03 mate is motivating in its own right, well, what are you going 853 00:48:03 --> 00:48:06 to do, you know, wait around until all of a sudden, I don't 854 00:48:06 --> 00:48:08 know, whatever levels it is drops low enough, ugh, 855 00:48:08 --> 00:48:12 it's time to mate? 856 00:48:12 --> 00:48:15 It's just not the way we organize our, it's not the way 857 00:48:15 --> 00:48:19 we organize our behavior. 858 00:48:19 --> 00:48:24 Our social lives suggest that we find a degree of pleasure 859 00:48:24 --> 00:48:30 in the appetitive aspects of seeking a mate, not merely in 860 00:48:30 --> 00:48:33 the consummatory parts of it. 861 00:48:33 --> 00:48:43 So you come with a set of motivations that get you 862 00:48:43 --> 00:48:47 motivation, in the sense of getting you to move, that seem 863 00:48:47 --> 00:48:49 to come with the systems. 864 00:48:49 --> 00:48:55 These can be quite specific -- by the way, that's the notion 865 00:48:55 --> 00:48:58 of preparedness that I see, what is related to this notion 866 00:48:58 --> 00:49:00 of preparedness that I see is actually above where it says 867 00:49:00 --> 00:49:09 consummatory and appetitive behaviors on the handout. 868 00:49:09 --> 00:49:18 you are surprisingly fine tuned by, presumably by the 869 00:49:18 --> 00:49:20 history of the species. 870 00:49:20 --> 00:49:28 So for instance, you are built to get away from scary things 871 00:49:28 --> 00:49:33 that are going to hurt you and that seems reasonable enough. 872 00:49:33 --> 00:49:36 And that can be specific enough to the point that it's easier 873 00:49:36 --> 00:49:40 to get you to be scared of spiders and snakes than it 874 00:49:40 --> 00:49:44 is to get you to be scared of bunnies and chickens. 875 00:49:44 --> 00:49:46 That sounds kind of obvious, but there's no obvious reason 876 00:49:46 --> 00:49:49 why, in fact, one of the famous experiments in the sort of 877 00:49:49 --> 00:49:53 behaviorists tradition has a little baby known to history as 878 00:49:53 --> 00:49:56 Little Albert -- there's a great film from the 20's of 879 00:49:56 --> 00:49:58 this Little Albert is sitting there, he's playing with 880 00:49:58 --> 00:50:00 a little white bunny. 881 00:50:00 --> 00:50:03 John Watson, founder of American behaviors, then sneaks 882 00:50:03 --> 00:50:09 up behind Little Albert with a gong and pow, rings the gong. 883 00:50:09 --> 00:50:12 Little Albert goes, if it was a cartoon, would go straight up 884 00:50:12 --> 00:50:15 in the air, and is you know, scared out of his Little Albert 885 00:50:15 --> 00:50:21 gourd and is screaming and crying and stuff like that, and 886 00:50:21 --> 00:50:25 you know, it's kind of harsh for Little Albert, but then you 887 00:50:25 --> 00:50:28 bring Albert back and show him the bunny again. 888 00:50:28 --> 00:50:30 Does he want to play with the bunny? 889 00:50:30 --> 00:50:31 No. 890 00:50:31 --> 00:50:33 Does he want to play with anything that's white and 891 00:50:33 --> 00:50:36 furry, including Santa Claus, apparently, I seem to recall. 892 00:50:36 --> 00:50:39 Guys with bushy white beards -- he recovered by the way. 893 00:50:39 --> 00:50:43 He didn't grow up to be a psycho or anything, but you can 894 00:50:43 --> 00:50:46 train, so you can you can train somebody to be scared of 895 00:50:46 --> 00:50:50 rabbits, but it's easier to train them to be scared of 896 00:50:50 --> 00:50:54 snakes, at if they were prepared by the history of the 897 00:50:54 --> 00:51:05 species to be scared of things like snakes and spiders. 898 00:51:05 --> 00:51:11 OK, so you're a slave to the environment because your brain 899 00:51:11 --> 00:51:16 responds in rather specific ways to the environment but you 900 00:51:16 --> 00:51:24 are a lot more complicated than that, or at least you feel like 901 00:51:24 --> 00:51:27 you're a lot more complicated than something that's just a 902 00:51:27 --> 00:51:31 bundle of sort of engineering responses to glucose level 903 00:51:31 --> 00:51:35 low, must go find wildebeest. 904 00:51:35 --> 00:51:38 And I want to spend the remainder of the lecture 905 00:51:38 --> 00:51:42 talking about some of those complexities, but first I want 906 00:51:42 --> 00:51:47 to give everybody a chance at least to stand up and stretch a 907 00:51:47 --> 00:51:49 little bit and fan themselves because it's warm in here. 908 00:51:49 --> 00:51:57 909 00:51:57 --> 00:52:32 I Oh, yes, yes you want your little form right now? 910 00:52:32 --> 00:52:33 AUDIENCE: Sure. 911 00:52:33 --> 00:52:37 PROFESSOR: Ok send this form back, and I trust that means 912 00:52:37 --> 00:52:40 that you can be here at like five of two -- 913 00:52:40 --> 00:52:40 AUDIENCE: [UNINTELLIGIBLE] 914 00:52:40 --> 00:52:44 PROFESSOR: Yes, well, it's not useful after class. 915 00:52:44 --> 00:52:46 OK this is all the information I have. 916 00:52:46 --> 00:52:48 If there's a problem let me know. 917 00:52:48 --> 00:52:50 And your name is? 918 00:52:50 --> 00:52:51 AUDIENCE: Jean. 919 00:52:51 --> 00:52:52 PROFESSOR: Jean, nice to meet you, and I trust that you'll 920 00:52:52 --> 00:52:57 see happily erasing my boards. 921 00:52:57 --> 00:53:01 OK, let us reconvene here. 922 00:53:01 --> 00:53:07 Here's the deal. 923 00:53:07 --> 00:53:17 I will typically try to be good and remember to give you a 924 00:53:17 --> 00:53:22 chance to sort of stretch your limbs a little bit, and, but 925 00:53:22 --> 00:53:24 it'll be a short stretch. 926 00:53:24 --> 00:53:27 So, you know, but why am I telling you this? 927 00:53:27 --> 00:53:29 It's the guys who thought they were off for ten minutes who 928 00:53:29 --> 00:53:31 are now halfway down the hall to get the M&Ms who had 929 00:53:31 --> 00:53:34 the problem, but anyway. 930 00:53:34 --> 00:53:36 Or the ones who are out looking for wildebeest 931 00:53:36 --> 00:53:37 are really in trouble. 932 00:53:37 --> 00:53:40 933 00:53:40 --> 00:53:44 You might wonder what the role of the emotion 934 00:53:44 --> 00:53:45 is in all of this. 935 00:53:45 --> 00:53:48 Clearly, motivation and emotion are closely related. 936 00:53:48 --> 00:53:52 They both talk about feeling a lot, you know, that there's 937 00:53:52 --> 00:54:03 this feeling of hunger, but the emotion part is well, one way 938 00:54:03 --> 00:54:07 to think of it would be as a sort of a language, a symbol 939 00:54:07 --> 00:54:14 system, that's a short hand that helps you mobilize you, a 940 00:54:14 --> 00:54:18 way of talking to yourself about what resources you 941 00:54:18 --> 00:54:18 might want to mobilize. 942 00:54:18 --> 00:54:21 Oh, I feel fear. 943 00:54:21 --> 00:54:27 That means I should do the following sorts of things. 944 00:54:27 --> 00:54:30 And it helps you generalize from event to event. 945 00:54:30 --> 00:54:32 I feel fear now. 946 00:54:32 --> 00:54:34 I felt fear before. 947 00:54:34 --> 00:54:36 You know, maybe there's some sort of relationship that 948 00:54:36 --> 00:54:41 I ought to be noticing. 949 00:54:41 --> 00:54:46 And perhaps, one of its most important uses is as a form of 950 00:54:46 --> 00:54:52 communication between people or between animals more generally. 951 00:54:52 --> 00:54:54 If I am afraid, let's go let's go back to the plains of 952 00:54:54 --> 00:54:57 Africa and switch sides. 953 00:54:57 --> 00:55:02 If I'm a wildebeest, and I see the leopard over there, 954 00:55:02 --> 00:55:07 stalking through the under brush, I should be afraid. 955 00:55:07 --> 00:55:09 If you're not seeing the leopard, but you're seeing me, 956 00:55:09 --> 00:55:12 I look afraid, and you're the rest of the wildebeests, 957 00:55:12 --> 00:55:14 you should be afraid too. 958 00:55:14 --> 00:55:19 It's a good idea if you pick up on the way that I feel. 959 00:55:19 --> 00:55:26 Now we tend to devalue that a bit because we tend to use 960 00:55:26 --> 00:55:31 verbal communication a lot to convey information back and 961 00:55:31 --> 00:55:33 forth, and for some things it's obviously a much 962 00:55:33 --> 00:55:36 more useful technique. 963 00:55:36 --> 00:55:39 I mean trying to teach psychology by a set of 964 00:55:39 --> 00:55:44 emotional expressions would not -- I can't even conceive of how 965 00:55:44 --> 00:55:46 I would go about doing that. 966 00:55:46 --> 00:55:52 However, we probably over value the straight, this sort of 967 00:55:52 --> 00:55:55 straight verbal nature of communications, even 968 00:55:55 --> 00:55:55 between humans. 969 00:55:55 --> 00:55:58 Obviously, non-verbal animals are going to have to use some 970 00:55:58 --> 00:56:02 other form of communication, but even among humans, we 971 00:56:02 --> 00:56:08 underrate the value of this current of emotion 972 00:56:08 --> 00:56:10 information transmission. 973 00:56:10 --> 00:56:19 Perhaps the clearest example of this is email, where, how many 974 00:56:19 --> 00:56:24 of you at some point have gotten into trouble on email, 975 00:56:24 --> 00:56:29 because email has the characteristics of conversation 976 00:56:29 --> 00:56:33 without the tone of voice. 977 00:56:33 --> 00:56:37 You said something that you thought, that you meant 978 00:56:37 --> 00:56:41 sarcastically, or you thought was funny, and somebody else 979 00:56:41 --> 00:56:46 read it as flat prose, and they were not amused at all. 980 00:56:46 --> 00:56:53 And then you got -- actually that's the root of all these 981 00:56:53 --> 00:56:55 little smiley faces and all these symbols that I 982 00:56:55 --> 00:56:58 don't know from nothing. 983 00:56:58 --> 00:56:59 You all know this. 984 00:56:59 --> 00:57:01 There's some very elaborate vocabulary of basically 985 00:57:01 --> 00:57:09 emotional tokens for instant messaging or for email because 986 00:57:09 --> 00:57:13 it lacks that emotional tone of voice, and without that, 987 00:57:13 --> 00:57:18 the quality of the communication goes down. 988 00:57:18 --> 00:57:21 989 00:57:21 --> 00:57:28 So you've got emotions at sort of a super ordinate language 990 00:57:28 --> 00:57:32 that allows you to talk about motivational states, even in 991 00:57:32 --> 00:57:34 the absence of any sort of verbal language. 992 00:57:34 --> 00:57:38 I think you could probably make a convincing argument that 993 00:57:38 --> 00:57:44 basic motivational states exist in very, very simple organisms. 994 00:57:44 --> 00:57:49 I mean any organism has to figure out, has to have in some 995 00:57:49 --> 00:57:53 sense the motivation to feed itself and to reproduce. 996 00:57:53 --> 00:57:56 It's only when you get to more elaborate organisms do you get 997 00:57:56 --> 00:58:00 something that looks like the sort of emotional life that you 998 00:58:00 --> 00:58:04 and I might have, where it's being used, as a sense, a 999 00:58:04 --> 00:58:05 form of communication. 1000 00:58:05 --> 00:58:12 But look, so far, we're still in pretty simple terms here. 1001 00:58:12 --> 00:58:15 You know, we've got, sex and reproduction is good. 1002 00:58:15 --> 00:58:19 Getting eaten by the leopard, that's bad, and so on. 1003 00:58:19 --> 00:58:24 Where we want to get, and where the chapter on motivation, for 1004 00:58:24 --> 00:58:29 instance, never gets, is you know, sex and reproduction, 1005 00:58:29 --> 00:58:32 good, eternal damnation, bad. 1006 00:58:32 --> 00:58:33 Or something like that. 1007 00:58:33 --> 00:58:36 Or how do you get from, you know, hunger drives and sex 1008 00:58:36 --> 00:58:41 drives to thou shall not murder and you know, I want to grow up 1009 00:58:41 --> 00:58:46 to be a chemical engineer, or something like that. 1010 00:58:46 --> 00:58:51 It's those rather more complicated motivations that 1011 00:58:51 --> 00:58:58 require more than just feedback loops and the lateral 1012 00:58:58 --> 00:59:02 hypothalamus to make a good story. 1013 00:59:02 --> 00:59:10 Now, one step to a richer account of why we do 1014 00:59:10 --> 00:59:14 anything is to broaden the set of motivations. 1015 00:59:14 --> 00:59:23 I have pointed already in the direction of one act of 1016 00:59:23 --> 00:59:29 broadening that set, and that is this notion that if I'm a 1017 00:59:29 --> 00:59:31 frightened wildebeest, you should be a frightened 1018 00:59:31 --> 00:59:32 wildebeest. 1019 00:59:32 --> 00:59:35 This is the notion that emotions are catching 1020 00:59:35 --> 00:59:37 across individuals. 1021 00:59:37 --> 00:59:42 We talk about, on the handout I put it as empathy and described 1022 00:59:42 --> 00:59:53 it as a social emotion, and it's a social emotion in the 1023 00:59:53 --> 00:59:59 sense that it helps to organize social behavior, interactions 1024 00:59:59 --> 01:00:01 between people. 1025 01:00:01 --> 01:00:07 So, for example, well let's start with a bit of evidence 1026 01:00:07 --> 01:00:10 that this comes with the system, that it's not 1027 01:00:10 --> 01:00:13 something, I mean you spend a fair amount of time trying to 1028 01:00:13 --> 01:00:16 teach people to be more empathic, but the core of it 1029 01:00:16 --> 01:00:17 is there from the start. 1030 01:00:17 --> 01:00:19 So, how do you know it's there from the start? 1031 01:00:19 --> 01:00:23 You take a baby, here's a baby, here's a bunch of other babies. 1032 01:00:23 --> 01:00:24 Poke this baby. 1033 01:00:24 --> 01:00:26 What's this baby do? 1034 01:00:26 --> 01:00:27 AUDIENCE: Cry. 1035 01:00:27 --> 01:00:27 PROFESSOR: Cry. 1036 01:00:27 --> 01:00:29 What do these babies do? 1037 01:00:29 --> 01:00:31 They also cry. 1038 01:00:31 --> 01:00:31 Why? 1039 01:00:31 --> 01:00:34 You haven't hurt those babies, but those babies have, in a 1040 01:00:34 --> 01:00:41 sense, caught the emotional state of the other baby. 1041 01:00:41 --> 01:00:45 Not only do babies catch their emotional, each other's 1042 01:00:45 --> 01:00:55 emotional states, but you are all here today because of the 1043 01:00:55 --> 01:00:57 same sort of empathic reaction. 1044 01:00:57 --> 01:01:03 When you were a little pre-verbal slug, and you were 1045 01:01:03 --> 01:01:07 hungry, what did you do? 1046 01:01:07 --> 01:01:07 AUDIENCE: Cried. 1047 01:01:07 --> 01:01:09 PROFESSOR: Yeah, right, you cried, right, is 1048 01:01:09 --> 01:01:11 all you could do. 1049 01:01:11 --> 01:01:14 And how did that make your parents feel? 1050 01:01:14 --> 01:01:17 1051 01:01:17 --> 01:01:20 Well, some of you are here today because you were lucky 1052 01:01:20 --> 01:01:24 because apparently it made your parents feel angry, and then -- 1053 01:01:24 --> 01:01:28 which it probably did, particularly at weird hours -- 1054 01:01:28 --> 01:01:30 Mara is looking at me. 1055 01:01:30 --> 01:01:31 How old is the kid? 1056 01:01:31 --> 01:01:33 AUDIENCE: Four-and-a-half months. 1057 01:01:33 --> 01:01:33 PROFESSOR: Four-and-a-half months. 1058 01:01:33 --> 01:01:37 We can check out -- if you haven't met Mara, she's the 1059 01:01:37 --> 01:01:40 head TA, so she knows everything about the course and 1060 01:01:40 --> 01:01:44 what recitation you're in, and we can also use her all-term as 1061 01:01:44 --> 01:01:48 the official parent person, or at least parent of young 1062 01:01:48 --> 01:01:52 child type person. 1063 01:01:52 --> 01:01:56 She will confirm that when you're baby cries, you want to 1064 01:01:56 --> 01:01:58 make that baby stop crying. 1065 01:01:58 --> 01:02:02 Fortunately, most parents, the ones who want their genes to 1066 01:02:02 --> 01:02:06 make it into the next m make the baby stop crying by doing 1067 01:02:06 --> 01:02:09 things like feeding it and changing it and 1068 01:02:09 --> 01:02:10 stuff like that. 1069 01:02:10 --> 01:02:15 If it didn't make you feel bad, if the crying baby wasn't 1070 01:02:15 --> 01:02:20 the car alarm of the developmental world. 1071 01:02:20 --> 01:02:21 Hey, the baby is crying. 1072 01:02:21 --> 01:02:24 Oh, that's cool, you know? 1073 01:02:24 --> 01:02:26 Didn't know the baby could make that noise. 1074 01:02:26 --> 01:02:30 Wonder what happens in a little -- the baby cries, 1075 01:02:30 --> 01:02:34 you feel bad, and you doing something about it. 1076 01:02:34 --> 01:02:41 And, you know, that's how you end up getting there, getting 1077 01:02:41 --> 01:02:46 to the point where you can take care of yourself, because 1078 01:02:46 --> 01:02:50 somebody else was willing to take care of you at that point. 1079 01:02:50 --> 01:02:54 And obviously, again, in non-verbal animals, like the 1080 01:02:54 --> 01:03:01 rest of them, it's really useful if, when your infant 1081 01:03:01 --> 01:03:04 animal is feeling uncomfortable, you recognize 1082 01:03:04 --> 01:03:07 the need in some fashion and you and you do 1083 01:03:07 --> 01:03:07 something about it. 1084 01:03:07 --> 01:03:10 So in a sense, emphathy is sort of a prerequisite 1085 01:03:10 --> 01:03:15 for successful parenting. 1086 01:03:15 --> 01:03:20 And this empathic catching of fear is a useful way 1087 01:03:20 --> 01:03:21 to keep yourself alive. 1088 01:03:21 --> 01:03:25 If you don't see the danger, but somebody else does, that's 1089 01:03:25 --> 01:03:30 -- oh, and it's a good, it's good for keeping you 1090 01:03:30 --> 01:03:32 alive in other ways too. 1091 01:03:32 --> 01:03:38 I won't do it, but if I were to suddenly decide to make myself 1092 01:03:38 --> 01:03:43 throw-up, a bunch of you would feel really lousy, right? 1093 01:03:43 --> 01:03:44 You know this. 1094 01:03:44 --> 01:03:46 By the way, this is one that goes away when 1095 01:03:46 --> 01:03:47 you become a parent. 1096 01:03:47 --> 01:03:50 You can modulate these things over -- if you felt 1097 01:03:50 --> 01:03:54 incapacitatedly nauseous every time your child threw-up, your 1098 01:03:54 --> 01:03:57 child would never make it, because -- you just got 1099 01:03:57 --> 01:03:59 to deal and clean up. 1100 01:03:59 --> 01:04:03 But at this point, if I throw up, you're going to feel sick. 1101 01:04:03 --> 01:04:04 Some of you will throw up. 1102 01:04:04 --> 01:04:06 I shouldn't keep talking about it because some of you will 1103 01:04:06 --> 01:04:09 start feeling gross just thinking about it. 1104 01:04:09 --> 01:04:10 That's also useful. 1105 01:04:10 --> 01:04:11 Why? 1106 01:04:11 --> 01:04:14 Because if I ate the wildebeest, and it was a bad 1107 01:04:14 --> 01:04:18 wildebeest, you know, and we're all vultures on the same 1108 01:04:18 --> 01:04:22 wildebeest here, if I'm looking kind of sick, you might as well 1109 01:04:22 --> 01:04:24 get rid of wildebeest now, because it's just not going to 1110 01:04:24 --> 01:04:26 be doing you any good. 1111 01:04:26 --> 01:04:32 So this catching businesses has its utility. 1112 01:04:32 --> 01:04:35 Now it's not uniformly a good thing, because you can catch 1113 01:04:35 --> 01:04:38 anti- social emotions just the way you can catch 1114 01:04:38 --> 01:04:40 pro- social emotions. 1115 01:04:40 --> 01:04:44 So when you see seemingly incomprehensible events, like 1116 01:04:44 --> 01:04:48 how in the world can you explain something like gang 1117 01:04:48 --> 01:04:54 rape or a massacre in a war zone? 1118 01:04:54 --> 01:04:59 Part of what's going on there is the same sort 1119 01:04:59 --> 01:05:00 of emotional contagion. 1120 01:05:00 --> 01:05:07 If one person is in a murderous rage, people around them, 1121 01:05:07 --> 01:05:09 around that person, can catch the murderous rage, just 1122 01:05:09 --> 01:05:14 the way they can catch the fear or catch the nausea. 1123 01:05:14 --> 01:05:23 It's not just sort of a pro social motivation, but empathy 1124 01:05:23 --> 01:05:27 does serve the function of organizing larger scale 1125 01:05:27 --> 01:05:30 sorts of behavior. 1126 01:05:30 --> 01:05:33 Oh, now, how does this contagion actually work? 1127 01:05:33 --> 01:05:35 How does emotional contagion actually work? 1128 01:05:35 --> 01:05:39 Interestingly, part of, the sort of reflexive mechanism 1129 01:05:39 --> 01:05:44 of it seems to be that when you read my emotion, you 1130 01:05:44 --> 01:05:47 also mimic my emotion. 1131 01:05:47 --> 01:05:49 It is most clearly seen with facial expression. 1132 01:05:49 --> 01:05:53 If I smile at you, you will smile. 1133 01:05:53 --> 01:05:56 You may not smile much, but I'd be able to pick up, if I was 1134 01:05:56 --> 01:06:00 recording from your facial muscles, I would be able to 1135 01:06:00 --> 01:06:06 pick up a transient smile flitting across your face. 1136 01:06:06 --> 01:06:07 Why is that important? 1137 01:06:07 --> 01:06:12 Well how do you know if you are happy? 1138 01:06:12 --> 01:06:17 Well, it turns out -- and this is, one of the senses in which 1139 01:06:17 --> 01:06:21 feelings, emotions our feelings is that you go out and 1140 01:06:21 --> 01:06:27 you feel yourself and ask yourself, how do I feel? 1141 01:06:27 --> 01:06:30 Part of that is to feel your face, in effect. 1142 01:06:30 --> 01:06:32 You know, how does my face feel? 1143 01:06:32 --> 01:06:34 Well, I seem to be smiling. 1144 01:06:34 --> 01:06:35 Why would I be smiling? 1145 01:06:35 --> 01:06:39 I must be smiling because I feel good because only dumb 1146 01:06:39 --> 01:06:41 people smile when they're miserable, right. 1147 01:06:41 --> 01:06:44 You know, well, there are various social circumstances 1148 01:06:44 --> 01:06:48 when you might do that, but anyway, it's useful 1149 01:06:48 --> 01:06:49 information. 1150 01:06:49 --> 01:06:52 You can actually try to demonstrate this -- here's an 1151 01:06:52 --> 01:06:57 exercise for the reader if you like, I've done it as one of 1152 01:06:57 --> 01:07:00 the writing assignments for the course in various years. 1153 01:07:00 --> 01:07:01 It's sort of fun. 1154 01:07:01 --> 01:07:05 Take say ten events of about the same duration, say an hour, 1155 01:07:05 --> 01:07:10 because that works for a lecture, for example, now a 1156 01:07:10 --> 01:07:15 lecture, recitation, dinner, a few events, study break, 1157 01:07:15 --> 01:07:17 events that are going to take about an hour. 1158 01:07:17 --> 01:07:18 Take ten of them. 1159 01:07:18 --> 01:07:19 Shuffle them around. 1160 01:07:19 --> 01:07:21 Put five of them in one pile randomly, put five 1161 01:07:21 --> 01:07:23 in the other pile. 1162 01:07:23 --> 01:07:28 Then deliberately either try to smile or frown through, you 1163 01:07:28 --> 01:07:32 know, smile through pile A and frown through pile B. 1164 01:07:32 --> 01:07:35 And ask yourself, you can ask yourself a variety of 1165 01:07:35 --> 01:07:39 questions, the most obvious being, how do I feel, and 1166 01:07:39 --> 01:07:42 what's the effect on people around me? 1167 01:07:42 --> 01:07:50 If you frown like an idiot, the effect may be to make people 1168 01:07:50 --> 01:07:54 smile, but if you, but you know what you, you've done 1169 01:07:54 --> 01:07:55 the experiment. 1170 01:07:55 --> 01:07:58 You were doing it like when you were early adolescences is one 1171 01:07:58 --> 01:08:00 of the best times to do this particular experiment. 1172 01:08:00 --> 01:08:02 You show up at the dinner table. 1173 01:08:02 --> 01:08:07 Everybody's in a pretty good mood, but you're not. 1174 01:08:07 --> 01:08:11 By the end of the meal, you know that nobody's in a 1175 01:08:11 --> 01:08:13 good mood anymore, right? 1176 01:08:13 --> 01:08:15 Well, you can still do this. 1177 01:08:15 --> 01:08:17 I mean I'm not sure how ethical it is as an experiment to try 1178 01:08:17 --> 01:08:21 out on your friends at dinner tonight, but it you go to 1179 01:08:21 --> 01:08:26 dinner feeling like junk and acting that way, you can make 1180 01:08:26 --> 01:08:29 everybody else miserable too, and isn't that great? 1181 01:08:29 --> 01:08:33 But more to the point, for the present point, you can make 1182 01:08:33 --> 01:08:37 your -- all that's sappy garbage about a smile is your 1183 01:08:37 --> 01:08:40 umbrella turn out to be sort of true. 1184 01:08:40 --> 01:08:43 And it doesn't even have to be a real smile. 1185 01:08:43 --> 01:08:45 If you take, no that's somebody else's pen. 1186 01:08:45 --> 01:08:47 I'm not going to do it with somebody else's pen. 1187 01:08:47 --> 01:08:49 If you take a pen, this is an experiment that was published a 1188 01:08:49 --> 01:08:55 few years ago, take a pen and hold it like this, that forces 1189 01:08:55 --> 01:09:02 your face into sort of an idiot smile, whereas holding a 1190 01:09:02 --> 01:09:04 pen like this does not. 1191 01:09:04 --> 01:09:07 It forces, it actually forces into a bit of a frown. 1192 01:09:07 --> 01:09:10 If you do this, and don't -- I'm already spoiling the 1193 01:09:10 --> 01:09:11 control aspect of the experiment. 1194 01:09:11 --> 01:09:14 You don't tell people why they're doing this. 1195 01:09:14 --> 01:09:16 You just make them do it for awhile. 1196 01:09:16 --> 01:09:23 The people who do this feel better than the people who do 1197 01:09:23 --> 01:09:25 this, because the chunks of your brain that are saying, how 1198 01:09:25 --> 01:09:30 do I feel, are rolled up and encapsulated enough that they 1199 01:09:30 --> 01:09:33 don't know, he's smiling, he must feel good. 1200 01:09:33 --> 01:09:36 The fact that he's smiling because he's got a pen in his 1201 01:09:36 --> 01:09:39 mouth turns out -- not that it matters, but it doesn't 1202 01:09:39 --> 01:09:40 matter that much. 1203 01:09:40 --> 01:09:42 So if you're feeling down, bit on a pen, you'll feel 1204 01:09:42 --> 01:09:43 much better about it. 1205 01:09:43 --> 01:09:47 1206 01:09:47 --> 01:09:52 OK, well look, so you can get a certain amount of work done by 1207 01:09:52 --> 01:09:58 broadening the set of available emotions, available motivations 1208 01:09:58 --> 01:10:01 that you want to talk about. 1209 01:10:01 --> 01:10:04 Why isn't the world a better place? 1210 01:10:04 --> 01:10:07 You've got this empathy thing going on. 1211 01:10:07 --> 01:10:09 You've got this beautifully wired up brain that you're a 1212 01:10:09 --> 01:10:13 slave to that's designed to make you eat and mate and do 1213 01:10:13 --> 01:10:14 all those sort of good things. 1214 01:10:14 --> 01:10:16 Why isn't the world a better place? 1215 01:10:16 --> 01:10:19 Why doesn't it work better? 1216 01:10:19 --> 01:10:21 I point, look, I can't solve that in the remaining 1217 01:10:21 --> 01:10:22 12 minutes or so. 1218 01:10:22 --> 01:10:26 I pointed to part of the answer just because you catch emotions 1219 01:10:26 --> 01:10:28 doesn't necessarily mean you catch good ones. 1220 01:10:28 --> 01:10:32 It is also the case that not all of your motivations 1221 01:10:32 --> 01:10:34 may be entirely benign. 1222 01:10:34 --> 01:10:37 So, for example, what's it got on the handout? 1223 01:10:37 --> 01:10:45 It doesn't have on the handout, but aggression seems to be, 1224 01:10:45 --> 01:10:49 there seems to have deep biological roots to it. 1225 01:10:49 --> 01:10:55 It is a not unreasonable reaction to a world 1226 01:10:55 --> 01:10:57 of limited resources. 1227 01:10:57 --> 01:10:59 It's not necessarily a nice reaction to a world of limited 1228 01:10:59 --> 01:11:06 resources, but, you know, if you are, if there's a limited 1229 01:11:06 --> 01:11:13 number of mates out there, and you can punch out all the other 1230 01:11:13 --> 01:11:20 guys and grab all the women, well, then you get the have 1231 01:11:20 --> 01:11:24 more progney than the guys you punched out. 1232 01:11:24 --> 01:11:26 Fortunately human society is not organized 1233 01:11:26 --> 01:11:27 particularly that way. 1234 01:11:27 --> 01:11:30 But there are plenty of animal societies that seem to be, 1235 01:11:30 --> 01:11:35 elephant seals, you've seen these guys on, you know, your 1236 01:11:35 --> 01:11:37 favorite cable channel, right? 1237 01:11:37 --> 01:11:42 They come up in thousands on the beaches near Antarctica and 1238 01:11:42 --> 01:11:45 stuff, and, you know, these huge male guy elephant seals 1239 01:11:45 --> 01:11:50 have like a thousand women -- what is a woman elephant seal? 1240 01:11:50 --> 01:11:50 I don't know. 1241 01:11:50 --> 01:11:54 Anyway, a thousand female elephant seals in their harem, 1242 01:11:54 --> 01:11:57 and they have these huge fights over who gets to have a -- 1243 01:11:57 --> 01:11:59 you know, they can't share. 1244 01:11:59 --> 01:12:00 They just never went to preschool and learned 1245 01:12:00 --> 01:12:02 how to share properly. 1246 01:12:02 --> 01:12:06 But part of, there is certainly enough aggression in human 1247 01:12:06 --> 01:12:10 behavior to make it clear that that sort of a motivational 1248 01:12:10 --> 01:12:14 system is going to lead to a certain amount of conflict in 1249 01:12:14 --> 01:12:16 the world, and it's not all going to work out as 1250 01:12:16 --> 01:12:18 sweetness and light. 1251 01:12:18 --> 01:12:21 People like Freud proposed that there was actually a death 1252 01:12:21 --> 01:12:23 wish motivation out there. 1253 01:12:23 --> 01:12:29 Thanatos Freud's term. 1254 01:12:29 --> 01:12:33 I might talk about that more later in the term. 1255 01:12:33 --> 01:12:37 So that's, the possibility that there are motivations that 1256 01:12:37 --> 01:12:41 themselves are not particularly nice, if you like, is one 1257 01:12:41 --> 01:12:46 possible reason that the world is not a perfect place. 1258 01:12:46 --> 01:12:51 But perhaps the most useful way of understanding why the world 1259 01:12:51 --> 01:12:55 doesn't work out so well, necessarily, given all this 1260 01:12:55 --> 01:13:02 marvelous motivational hardware if you like that you've got is 1261 01:13:02 --> 01:13:06 that, look, most of the time when we study these things, we 1262 01:13:06 --> 01:13:08 study a motivation in isolation. 1263 01:13:08 --> 01:13:11 You want to study this cat's ability to learn about the 1264 01:13:11 --> 01:13:15 puzzle box and the relation to the motivation of hunger, 1265 01:13:15 --> 01:13:17 you take a hungry cat. 1266 01:13:17 --> 01:13:18 You put it in a box. 1267 01:13:18 --> 01:13:20 The only thing of any interest here is how to get out of 1268 01:13:20 --> 01:13:22 the box and get to the fish. 1269 01:13:22 --> 01:13:26 You know, the only thing of interest here is, you know, 1270 01:13:26 --> 01:13:28 there's a rat who is maybe a hungry rat. 1271 01:13:28 --> 01:13:30 In this case, he's got an electrode now in the feeding 1272 01:13:30 --> 01:13:32 centers of his brain. 1273 01:13:32 --> 01:13:35 And all the other things that a rat might do are just 1274 01:13:35 --> 01:13:37 not relevant here. 1275 01:13:37 --> 01:13:39 You don't operate in the world like that. 1276 01:13:39 --> 01:13:43 You operate in a much more complicated space. 1277 01:13:43 --> 01:13:46 I mean we can cartoon that here. 1278 01:13:46 --> 01:13:48 Here's you. 1279 01:13:48 --> 01:13:53 You know, if we got in the lab, maybe we can just do an 1280 01:13:53 --> 01:13:57 experiment on when you do or do not eat, but that's not what 1281 01:13:57 --> 01:14:00 you're dealing with out in -- well, alright, here is a way 1282 01:14:00 --> 01:14:02 to get to this question. 1283 01:14:02 --> 01:14:07 How many of you have ever eaten something when 1284 01:14:07 --> 01:14:10 you weren't hungry. 1285 01:14:10 --> 01:14:12 Well what's the matter with you, right? 1286 01:14:12 --> 01:14:14 You know, I just told you, you've got this elaborate 1287 01:14:14 --> 01:14:16 stuff I've already erased the lateral hypothalamus. 1288 01:14:16 --> 01:14:20 You've got a brain full of circuitry designed to make you 1289 01:14:20 --> 01:14:24 eat when you're hungry, and not to eat when you're not hungry. 1290 01:14:24 --> 01:14:28 And you don't look like that fury football with 1291 01:14:28 --> 01:14:30 a lesion in your brain. 1292 01:14:30 --> 01:14:33 So what's your problem that you're eating when 1293 01:14:33 --> 01:14:36 you're not hungry? 1294 01:14:36 --> 01:14:39 Well all right, let think about this is sort of 1295 01:14:39 --> 01:14:40 metaphorical terms. 1296 01:14:40 --> 01:14:44 Let's imagine a situation where there are lots of different 1297 01:14:44 --> 01:14:45 possibilities pulling on you. 1298 01:14:45 --> 01:14:49 Suppose you're at some sort of a social gathering of some 1299 01:14:49 --> 01:14:51 sort, there are lots of possible things, lots of 1300 01:14:51 --> 01:14:55 motivational systems at work at any one time. 1301 01:14:55 --> 01:14:59 I mean one of the things you could probably do is eat. 1302 01:14:59 --> 01:15:09 Maybe there's the possibility for fighting, mating, 1303 01:15:09 --> 01:15:14 sleep, study. 1304 01:15:14 --> 01:15:22 You know, you could do all sorts of, you know, run. 1305 01:15:22 --> 01:15:25 You could do all sorts of stuff. 1306 01:15:25 --> 01:15:28 And all of these things, each of which may have it's own 1307 01:15:28 --> 01:15:34 beautiful hard- wired core and it's an elaboration of a 1308 01:15:34 --> 01:15:37 lifetime of learning, all of these things are pulling 1309 01:15:37 --> 01:15:40 on you at once. 1310 01:15:40 --> 01:15:42 And, well, you know, all right, so maybe the sleep motivation 1311 01:15:42 --> 01:15:46 and the study motivation are pretty weak at any given 1312 01:15:46 --> 01:15:48 moment, but you know, let's suppose that there's pretty 1313 01:15:48 --> 01:15:54 strong drives in this direction. 1314 01:15:54 --> 01:15:58 OK, so if you're sitting in this exciting vector field, 1315 01:15:58 --> 01:15:59 where the resultant? 1316 01:15:59 --> 01:16:00 Right? 1317 01:16:00 --> 01:16:01 Right. 1318 01:16:01 --> 01:16:06 AUDIENCE: [Laughter] 1319 01:16:06 --> 01:16:10 PROFESSOR: Now, I'm not proposing this as a serious 1320 01:16:10 --> 01:16:17 model of why you might eat when, well I am proposing it as 1321 01:16:17 --> 01:16:21 -- I'm not proposing it as a serious mathematical model of 1322 01:16:21 --> 01:16:24 why you might eat, but I'm supposing it has a serious 1323 01:16:24 --> 01:16:29 metaphor, that you might engage, and it's going to be 1324 01:16:29 --> 01:16:34 much more complicated than this, right, I mean part of the 1325 01:16:34 --> 01:16:37 reason, it's not just that there's, you know, want to eat? 1326 01:16:37 --> 01:16:38 Want to fight? 1327 01:16:38 --> 01:16:41 Oh think I'll go eat instead. 1328 01:16:41 --> 01:16:44 But, want to mate, you know, here? 1329 01:16:44 --> 01:16:46 Now? 1330 01:16:46 --> 01:16:50 Can't do that, but they're, you know, there those brain stem 1331 01:16:50 --> 01:16:53 chunks of general arousal, oh yeah, well, I've sort of got a 1332 01:16:53 --> 01:16:56 lot of activity here that I gotta do something. 1333 01:16:56 --> 01:16:58 So you end up with sort of displacement activity. 1334 01:16:58 --> 01:17:07 The problem is that the world is a complicated place, and if 1335 01:17:07 --> 01:17:10 you were ever going to reduce this to map, it's going to 1336 01:17:10 --> 01:17:12 have a lot of variables. 1337 01:17:12 --> 01:17:16 It's going to end up with a lot of variables in the equation. 1338 01:17:16 --> 01:17:18 Most of us manage to do OK. 1339 01:17:18 --> 01:17:23 We eat when we don't want, but that's all right. 1340 01:17:23 --> 01:17:26 Later on in the course, you end up talking about, you know, 1341 01:17:26 --> 01:17:30 perhaps the people where you find that they're fighting too 1342 01:17:30 --> 01:17:32 much or something like that. 1343 01:17:32 --> 01:17:35 1344 01:17:35 --> 01:17:38 No lecture Thursday, just to reiterate, I will sign all 1345 01:17:38 --> 01:17:40 those lovely add drop cards. 1346 01:17:40 --> 01:17:41 I'll see you next week. 1347 01:17:41 --> 01:17:43