1 00:00:00,770 --> 00:00:03,200 The following content is provided under a Creative 2 00:00:03,200 --> 00:00:04,610 Commons license. 3 00:00:04,610 --> 00:00:07,640 Your support will help MIT OpenCourseWare continue to 4 00:00:07,640 --> 00:00:11,300 offer high quality educational resources for free. 5 00:00:11,300 --> 00:00:14,190 To make a donation, or view additional materials from 6 00:00:14,190 --> 00:00:20,020 hundreds of MIT courses, visit MIT OpenCourseWare at 7 00:00:20,020 --> 00:00:21,270 ocw.mit.edu. 8 00:00:33,370 --> 00:00:36,850 PROFESSOR: OK, good afternoon. 9 00:00:36,850 --> 00:00:40,146 Today's lecture is going to be on child development. 10 00:00:40,146 --> 00:00:44,195 How they go from infancy and head towards adulthood. 11 00:00:44,195 --> 00:00:48,668 Next Thursday we'll talk about development after infancy and 12 00:00:48,668 --> 00:00:51,153 into adulthood and over age. 13 00:00:51,153 --> 00:00:53,935 And this amazing thing about babies and how do they get 14 00:00:53,935 --> 00:00:56,850 going, and how do scientists discover from babies and young 15 00:00:56,850 --> 00:00:59,340 children how their minds are fundamentally 16 00:00:59,340 --> 00:01:01,680 different than adults. 17 00:01:01,680 --> 00:01:04,739 And how your mind was fundamentally different than 18 00:01:04,739 --> 00:01:05,580 it is as an adult. 19 00:01:05,580 --> 00:01:10,230 And then the last thing will be a dangerous experiment, 20 00:01:10,230 --> 00:01:13,420 where my wife will come over with my two-year-old and my 21 00:01:13,420 --> 00:01:15,370 four-year-old and we'll try to do a developmental 22 00:01:15,370 --> 00:01:16,520 demonstration in front of you. 23 00:01:16,520 --> 00:01:19,520 But I should warn you that live children 24 00:01:19,520 --> 00:01:20,420 have their own will. 25 00:01:20,420 --> 00:01:23,280 So we'll see how that goes, okay? 26 00:01:23,280 --> 00:01:24,420 All right. 27 00:01:24,420 --> 00:01:28,080 So one thing that people are struck by babies is that 28 00:01:28,080 --> 00:01:29,680 babies are cute. 29 00:01:29,680 --> 00:01:32,300 And it's not just-- 30 00:01:32,300 --> 00:01:35,780 It's thought to be not just fun, but kind of a really 31 00:01:35,780 --> 00:01:37,570 important biological thing. 32 00:01:37,570 --> 00:01:39,310 We talked about motherese before. 33 00:01:39,310 --> 00:01:42,410 Singsong talk to babies that help them learn a language. 34 00:01:42,410 --> 00:01:45,710 There's something about adults finding babies cute that makes 35 00:01:45,710 --> 00:01:47,760 them want to help babies. 36 00:01:47,760 --> 00:01:49,550 Parents and friends-- 37 00:01:49,550 --> 00:01:54,620 The cuteness is thought to be an evolutionary reward for 38 00:01:54,620 --> 00:01:56,640 dealing with a baby. 39 00:01:56,640 --> 00:01:58,270 And people have said, well what is it that's a little bit 40 00:01:58,270 --> 00:02:00,710 different about a baby's face than an adult? 41 00:02:00,710 --> 00:02:03,190 They have rounder heads, they have foreheads that protrude 42 00:02:03,190 --> 00:02:05,670 more towards-- 43 00:02:05,670 --> 00:02:06,850 that slope back more. 44 00:02:06,850 --> 00:02:09,330 They have larger eyes proportionately. 45 00:02:09,330 --> 00:02:12,130 Smaller jaw bones proportionally. 46 00:02:12,130 --> 00:02:14,800 And people use the term neotony to describe this kind 47 00:02:14,800 --> 00:02:17,730 of infant proportions, or properties, of faces, which 48 00:02:17,730 --> 00:02:19,620 are universal. 49 00:02:19,620 --> 00:02:22,320 And, of course, a lot of people discover this in 50 00:02:22,320 --> 00:02:24,070 advertising or cartoons. 51 00:02:24,070 --> 00:02:28,040 And so here's an interesting example of how Mickey Mouse 52 00:02:28,040 --> 00:02:30,710 has, over the years, from the original version of Mickey 53 00:02:30,710 --> 00:02:35,100 Mouse to the current super cute, super tested, super 54 00:02:35,100 --> 00:02:38,620 Disney version of Mickey Mouse, has become increasingly 55 00:02:38,620 --> 00:02:39,400 neotonized. 56 00:02:39,400 --> 00:02:42,180 And how much the cartoonists literally know that, or just 57 00:02:42,180 --> 00:02:44,490 have kept saying, what makes cuter, and cuter, and cuter, 58 00:02:44,490 --> 00:02:47,015 and ended up with a lot of the same proportions in Mickey 59 00:02:47,015 --> 00:02:51,370 Mouse's face that make infants so cute and desirable. 60 00:02:51,370 --> 00:02:52,020 We don't really know. 61 00:02:52,020 --> 00:02:55,780 But the world kind of feels this. 62 00:02:55,780 --> 00:02:57,640 Even adult research-- there's a little funny line of 63 00:02:57,640 --> 00:03:02,410 research-- that says adults who look more baby-faced get 64 00:03:02,410 --> 00:03:04,225 treated a little bit different socially. 65 00:03:07,950 --> 00:03:10,330 So here's Leonardo DiCaprio. 66 00:03:10,330 --> 00:03:14,150 And baby-faced adults in experiments are perceived as, 67 00:03:14,150 --> 00:03:17,030 just by their faces, as more naive, more honest, more 68 00:03:17,030 --> 00:03:20,660 helpless, more kind, more warm. 69 00:03:20,660 --> 00:03:23,640 People think, this is going to be a nice warm person. 70 00:03:23,640 --> 00:03:26,980 Guessing from faces they're using the cues of neotony. 71 00:03:26,980 --> 00:03:30,170 Other studies have found that people who are baby-faced are 72 00:03:30,170 --> 00:03:34,200 statistically more likely to be found innocent in cases of 73 00:03:34,200 --> 00:03:36,070 intentional wrongdoing. 74 00:03:36,070 --> 00:03:38,760 So where they're trying to prove if somebody on purpose 75 00:03:38,760 --> 00:03:40,190 tried to do something bad, they go, not 76 00:03:40,190 --> 00:03:42,670 that cute little person. 77 00:03:42,670 --> 00:03:45,560 But there's no difference if it's cases that involve 78 00:03:45,560 --> 00:03:46,240 negligence. 79 00:03:46,240 --> 00:03:47,280 Something where you should have done something. 80 00:03:47,280 --> 00:03:49,640 Because we know babies aren't super responsible 81 00:03:49,640 --> 00:03:50,890 for how they behave. 82 00:03:55,470 --> 00:03:58,820 And they're less likely to receive votes in elections. 83 00:03:58,820 --> 00:04:00,100 So people have done-- 84 00:04:00,100 --> 00:04:01,710 I won't even tell you this-- but people have done all kinds 85 00:04:01,710 --> 00:04:04,405 of analyses of faces that win elections in the US 86 00:04:04,405 --> 00:04:05,680 and around the world. 87 00:04:05,680 --> 00:04:07,270 And there's two dimensions that people look for. 88 00:04:07,270 --> 00:04:09,890 What looks like somebody's empathetic and what looks like 89 00:04:09,890 --> 00:04:11,760 somebody's competent. 90 00:04:11,760 --> 00:04:14,010 So you want babies when it's fun, but when you have to 91 00:04:14,010 --> 00:04:16,260 figure out how to balance the budget that doesn't seem like 92 00:04:16,260 --> 00:04:18,399 a baby task. 93 00:04:18,399 --> 00:04:20,079 So it's kind of funny. 94 00:04:20,079 --> 00:04:25,680 And a lot of voters go by instincts as well as by facts 95 00:04:25,680 --> 00:04:27,440 or stated values. 96 00:04:27,440 --> 00:04:31,610 So in the development of infants into adults, the 97 00:04:31,610 --> 00:04:34,990 classic debates about how our mind grasps the world have 98 00:04:34,990 --> 00:04:37,520 played out, yet again, in a powerful way. 99 00:04:37,520 --> 00:04:38,970 You know, the nature-nurture debate. 100 00:04:38,970 --> 00:04:41,190 What's in our genes and gets us going? 101 00:04:41,190 --> 00:04:43,990 What's acquired from the environment? 102 00:04:43,990 --> 00:04:47,100 Philosophers who say that knowledge starts with innate, 103 00:04:47,100 --> 00:04:50,810 or genetic, or more evolved capacities. 104 00:04:50,810 --> 00:04:53,180 Other ones who've emphasized that we pick it up from the 105 00:04:53,180 --> 00:04:57,560 world empirically as measuring scientists. 106 00:04:57,560 --> 00:05:00,540 So, for example, Aristotle wrote, "There's nothing in the 107 00:05:00,540 --> 00:05:03,430 intellect which was not first in the senses." that's the 108 00:05:03,430 --> 00:05:04,310 empirical view. 109 00:05:04,310 --> 00:05:06,900 It's out there in the world and you solve it. 110 00:05:06,900 --> 00:05:09,200 And starting with a blank slate. 111 00:05:09,200 --> 00:05:11,980 And, in fact, the behaviorists believed in this with a 112 00:05:11,980 --> 00:05:13,540 vengeance in psychology. 113 00:05:13,540 --> 00:05:15,960 So Watson wrote, "Give me a dozen healthy infants, well 114 00:05:15,960 --> 00:05:18,980 formed, and my own specified world to bring them up. 115 00:05:18,980 --> 00:05:21,400 And I'll guarantee to take any of them, one at random, and 116 00:05:21,400 --> 00:05:24,610 train him to become any type of specialist I might select. 117 00:05:24,610 --> 00:05:26,910 A doctor, lawyer, artist, merchant, chief, and, yes, 118 00:05:26,910 --> 00:05:28,140 even beggerman and thief. 119 00:05:28,140 --> 00:05:30,660 That it's all the environment and a blank slate. 120 00:05:30,660 --> 00:05:33,700 And who really knows?" 121 00:05:33,700 --> 00:05:36,220 But infants are born with some incredible things, an we'll 122 00:05:36,220 --> 00:05:37,470 talk about them today. 123 00:05:37,470 --> 00:05:38,985 One of them is this experiment from Andy 124 00:05:38,985 --> 00:05:41,790 Meltzoff, which is this. 125 00:05:41,790 --> 00:05:45,460 That it seems like within moments of birth, infants are 126 00:05:45,460 --> 00:05:50,090 equipped with a desire to imitate adults. 127 00:05:50,090 --> 00:05:52,010 A desire to imitate. 128 00:05:52,010 --> 00:05:54,550 And why people have been really impressed by this is, 129 00:05:54,550 --> 00:05:58,900 if you have that in your genes and in your nature, it's a 130 00:05:58,900 --> 00:06:02,090 good way to learn about the world is to imitate people you 131 00:06:02,090 --> 00:06:03,070 see around you. 132 00:06:03,070 --> 00:06:04,930 It's kind of a driving principal. 133 00:06:04,930 --> 00:06:08,760 I'll imitate their language, their social mores. 134 00:06:08,760 --> 00:06:10,390 Here's what Meltzoff did. 135 00:06:10,390 --> 00:06:14,440 Sticks out his tongue, opens his mouth, purses his lips. 136 00:06:14,440 --> 00:06:18,960 And here's the infant, one day or a couple days old, tongue 137 00:06:18,960 --> 00:06:22,700 out, mouth open, lips pursed. 138 00:06:22,700 --> 00:06:24,510 Now, I should warn you about one thing. 139 00:06:24,510 --> 00:06:26,860 These are the greatest hits pieces of that research. 140 00:06:26,860 --> 00:06:28,480 People debate about how perfectly this 141 00:06:28,480 --> 00:06:29,600 happens, all right? 142 00:06:29,600 --> 00:06:32,070 So I was frustrated when my infant came home and I did all 143 00:06:32,070 --> 00:06:34,560 this stuff and she would not instantly do everything she 144 00:06:34,560 --> 00:06:35,830 was supposed to do. 145 00:06:35,830 --> 00:06:37,050 It's a statistical thing. 146 00:06:37,050 --> 00:06:39,230 Because when you see these pictures, they're showing you 147 00:06:39,230 --> 00:06:40,300 the best moments. 148 00:06:40,300 --> 00:06:43,090 They have to defend that it happens above chances 149 00:06:43,090 --> 00:06:43,720 statistically. 150 00:06:43,720 --> 00:06:45,370 But it's not like every expression you 151 00:06:45,370 --> 00:06:47,170 make they copy you. 152 00:06:47,170 --> 00:06:49,290 And that's why there's still some debate about exactly 153 00:06:49,290 --> 00:06:50,130 what's going on. 154 00:06:50,130 --> 00:06:53,740 But they definitely, on average, imitate an adult 155 00:06:53,740 --> 00:06:56,590 within a day or two of birth for completely arbitrary-- 156 00:06:56,590 --> 00:06:57,660 as far as we think-- 157 00:06:57,660 --> 00:06:58,900 expressions. 158 00:06:58,900 --> 00:07:01,400 So it's a very powerful mechanism for learning that 159 00:07:01,400 --> 00:07:02,410 appears to be in place. 160 00:07:02,410 --> 00:07:05,800 Because there's two ways that we could imagine genetically 161 00:07:05,800 --> 00:07:07,320 programmed learning. 162 00:07:07,320 --> 00:07:10,660 One is that you know the content of it already. 163 00:07:10,660 --> 00:07:12,760 But another way is that you just have stuff 164 00:07:12,760 --> 00:07:14,340 that makes you a learner. 165 00:07:14,340 --> 00:07:17,270 So being an imitator is a general way to make you a 166 00:07:17,270 --> 00:07:21,990 learner without being very specific to the content. 167 00:07:21,990 --> 00:07:24,680 So we talked a little bit about this already, but 168 00:07:24,680 --> 00:07:26,630 psychologists are unbelievably brilliant-- 169 00:07:26,630 --> 00:07:28,980 I think, I'm really blown away-- about how they can 170 00:07:28,980 --> 00:07:32,010 figure out when an infant knows and doesn't know, or 171 00:07:32,010 --> 00:07:33,740 young child knows or doesn't know. 172 00:07:33,740 --> 00:07:36,610 And they do this indirectly by things like looking time. 173 00:07:36,610 --> 00:07:37,550 And you've seen this. 174 00:07:37,550 --> 00:07:38,450 I'll give you an example or two. 175 00:07:38,450 --> 00:07:39,840 And you'll see some more examples. 176 00:07:39,840 --> 00:07:42,360 As a measure of what the baby knows, or 177 00:07:42,360 --> 00:07:43,690 the young child knows. 178 00:07:43,690 --> 00:07:45,760 And, of course, if they look longer at something it could 179 00:07:45,760 --> 00:07:48,220 be because they prefer it. 180 00:07:48,220 --> 00:07:51,760 And, also, if it's based on a memory task-- 181 00:07:51,760 --> 00:07:53,420 like you saw something, you see it again-- 182 00:07:53,420 --> 00:07:55,090 that would tell you there's some sort of discrimination . 183 00:07:55,090 --> 00:07:58,630 They can tell things apart based on memory. 184 00:07:58,630 --> 00:08:00,850 And then, sometimes, people will push this memory thing 185 00:08:00,850 --> 00:08:02,710 with habituation or familiarization, so if you 186 00:08:02,710 --> 00:08:07,490 show something to a baby over, and over, and over again, they 187 00:08:07,490 --> 00:08:09,140 get sort of tired of it. 188 00:08:09,140 --> 00:08:11,570 And at that moment they'll change the stimulus. 189 00:08:11,570 --> 00:08:15,050 And they'll see whether the baby gets newly attentive. 190 00:08:15,050 --> 00:08:18,340 Now, if it's something that the baby doesn't grasp, they 191 00:08:18,340 --> 00:08:19,610 won't get newly attentive. 192 00:08:19,610 --> 00:08:21,640 You know, nothing's changed in their mind. 193 00:08:21,640 --> 00:08:25,030 If it's something the baby understands, then they'll say, 194 00:08:25,030 --> 00:08:26,530 wow, something interesting is happening. 195 00:08:26,530 --> 00:08:28,210 And they'll look longer. 196 00:08:28,210 --> 00:08:30,070 So, here's an example. 197 00:08:30,070 --> 00:08:32,364 Baby getting bored because they're showing something over 198 00:08:32,364 --> 00:08:34,740 and over, and something new, oh! 199 00:08:34,740 --> 00:08:36,289 That's the kind of things that people measure. 200 00:08:36,289 --> 00:08:37,710 And we're doing it loosely here. 201 00:08:37,710 --> 00:08:38,740 They measure it pretty carefully. 202 00:08:38,740 --> 00:08:40,789 I should tell you, the people who do this kind of research-- 203 00:08:40,789 --> 00:08:44,800 they'll film it, they'll show it to unbiased people like 204 00:08:44,800 --> 00:08:45,760 you, maybe judges. 205 00:08:45,760 --> 00:08:47,790 OK, to say, how long is the baby looking? 206 00:08:47,790 --> 00:08:48,260 Where's it looking? 207 00:08:48,260 --> 00:08:51,300 You don't know where the baby should be looking at or not. 208 00:08:51,300 --> 00:08:54,230 So researchers take care to make it not just that you're 209 00:08:54,230 --> 00:08:55,680 convinced in your heart of hearts that 210 00:08:55,680 --> 00:08:56,370 they're looking more. 211 00:08:56,370 --> 00:08:57,290 They film it. 212 00:08:57,290 --> 00:08:58,970 They show it to people who don't know what's going on. 213 00:08:58,970 --> 00:09:01,010 They try to make it a blind procedure in many ways, the 214 00:09:01,010 --> 00:09:02,440 better research. 215 00:09:02,440 --> 00:09:03,610 So how do we know things? 216 00:09:03,610 --> 00:09:06,910 Even very young infants look selectively at novel objects. 217 00:09:06,910 --> 00:09:10,410 If something's new, even at one day, if you show them 218 00:09:10,410 --> 00:09:14,900 checkerboards with different size squares, same size, same 219 00:09:14,900 --> 00:09:18,850 size, same size, wait a couple seconds, smaller squares. 220 00:09:18,850 --> 00:09:20,240 They look more. 221 00:09:20,240 --> 00:09:22,520 This shows you they saw the difference in the squares. 222 00:09:22,520 --> 00:09:25,560 They even remember, somehow in their mind, the difference 223 00:09:25,560 --> 00:09:26,620 between the squares. 224 00:09:26,620 --> 00:09:28,890 Because when you switch it they start looking more. 225 00:09:28,890 --> 00:09:31,580 Something interesting has happened based on perception 226 00:09:31,580 --> 00:09:34,080 and memory. 227 00:09:34,080 --> 00:09:35,140 Another thing that we've mentioned-- 228 00:09:35,140 --> 00:09:37,290 I'll just remind you-- is that infants, almost from birth, 229 00:09:37,290 --> 00:09:40,720 seem to love to control, or provoke, their environment. 230 00:09:40,720 --> 00:09:43,350 So we already mentioned to you that 20 month olds prefer a 231 00:09:43,350 --> 00:09:46,310 mobile that responds to their bodily movements. 232 00:09:46,310 --> 00:09:47,940 They like things that they control. 233 00:09:47,940 --> 00:09:50,610 If they take a two-month-old, and they put a string on their 234 00:09:50,610 --> 00:09:53,509 wrist by which they can control a showing of Sesame 235 00:09:53,509 --> 00:09:57,260 Street, they kind of like that. 236 00:09:57,260 --> 00:09:59,910 And if you stop Sesame Street, they show anger on their face. 237 00:09:59,910 --> 00:10:03,210 Hey, I was in charge here, who has the remote control now. 238 00:10:03,210 --> 00:10:05,875 And four and five month olds, a little bit older, remain 239 00:10:05,875 --> 00:10:09,190 angry when the video comes back on because that's not 240 00:10:09,190 --> 00:10:09,930 what they wanted. 241 00:10:09,930 --> 00:10:12,850 They wanted to control the presentation of the video. 242 00:10:12,850 --> 00:10:17,470 So infants have this apparent craving to explore and feel 243 00:10:17,470 --> 00:10:20,470 like they have some control over their environment, at an 244 00:10:20,470 --> 00:10:22,820 age when they don't control a lot because of their limited 245 00:10:22,820 --> 00:10:25,460 physical capacity. 246 00:10:25,460 --> 00:10:28,290 In the first three or four months, infants explore the 247 00:10:28,290 --> 00:10:29,980 world a lot by their mouths. 248 00:10:29,980 --> 00:10:32,890 That's why people worry to not leave around things that they 249 00:10:32,890 --> 00:10:36,010 will put into their mouth and swallow, that are dangerous. 250 00:10:36,010 --> 00:10:38,070 Because their visual and auditory systems, and their 251 00:10:38,070 --> 00:10:40,460 system with their hand, are slowly developing. 252 00:10:40,460 --> 00:10:42,540 By five or six months around the world, they start to 253 00:10:42,540 --> 00:10:44,450 explore with their hands and their eyes around them. 254 00:10:44,450 --> 00:10:46,580 As their motor system gets more mature. 255 00:10:46,580 --> 00:10:50,120 As their visual system gains acuity. 256 00:10:50,120 --> 00:10:53,340 And we already know that infants use social cues to 257 00:10:53,340 --> 00:10:54,250 guide exploration. 258 00:10:54,250 --> 00:10:56,660 One of the big changes this happened in the last 10 years, 259 00:10:56,660 --> 00:11:00,880 I'd say, in infant studies or child studies, has been a lot 260 00:11:00,880 --> 00:11:04,230 of appreciation about the intersection between cognition 261 00:11:04,230 --> 00:11:05,590 and social interaction. 262 00:11:05,590 --> 00:11:07,365 There used to be like two different worlds of people who 263 00:11:07,365 --> 00:11:08,400 studied language. 264 00:11:08,400 --> 00:11:10,980 They would have algorithms and formulas about the language. 265 00:11:10,980 --> 00:11:13,400 And then the social people who'd study how babies were 266 00:11:13,400 --> 00:11:14,740 cute or something, right? 267 00:11:14,740 --> 00:11:17,400 But there's been more and more thought that a deep thing in 268 00:11:17,400 --> 00:11:20,980 us that helps cognition grow, is the social relations that 269 00:11:20,980 --> 00:11:24,140 an infant is drawn to parents and caretakers. 270 00:11:24,140 --> 00:11:28,250 So, for example, a six-month-old, if their mother 271 00:11:28,250 --> 00:11:31,850 rolls or pounds a ball, they tend to copy, they tend to 272 00:11:31,850 --> 00:11:34,270 imitate that action. 273 00:11:34,270 --> 00:11:36,180 They follow the eyes of a person. 274 00:11:36,180 --> 00:11:37,060 Joint attention. 275 00:11:37,060 --> 00:11:39,210 You know, eyes are the windows on the soul. 276 00:11:39,210 --> 00:11:40,540 We know eyes mean a lot. 277 00:11:40,540 --> 00:11:41,860 Where are people putting their attention? 278 00:11:41,860 --> 00:11:43,380 What are they paying attention to? 279 00:11:43,380 --> 00:11:45,750 Infants pick up on this very early on. 280 00:11:45,750 --> 00:11:48,720 And if somebody looks over there they look over there. 281 00:11:48,720 --> 00:11:50,540 If you look at them they know your attention 282 00:11:50,540 --> 00:11:52,030 is focused on them. 283 00:11:52,030 --> 00:11:53,730 And sometimes people will say-- 284 00:11:53,730 --> 00:11:55,570 because psychologists love to test everything-- is it just 285 00:11:55,570 --> 00:11:57,100 the way the head is turning? 286 00:11:57,100 --> 00:11:59,540 So if you cover somebody's head they 287 00:11:59,540 --> 00:12:00,760 don't follow it anymore. 288 00:12:00,760 --> 00:12:04,440 They know it has to be the eyes reflecting where the mind 289 00:12:04,440 --> 00:12:06,010 is putting its attention. 290 00:12:06,010 --> 00:12:07,230 It's not the head direction. 291 00:12:07,230 --> 00:12:09,500 It's the eyes. 292 00:12:09,500 --> 00:12:11,750 Here's something, infants who are a little bit better at 293 00:12:11,750 --> 00:12:13,200 following eyes-- 294 00:12:13,200 --> 00:12:14,800 either maturing faster or something-- 295 00:12:14,800 --> 00:12:16,810 also learn language faster. 296 00:12:16,810 --> 00:12:19,020 They get words faster, and syntax faster. 297 00:12:19,020 --> 00:12:22,100 It's as if part of that social interaction is helping to 298 00:12:22,100 --> 00:12:23,700 drive the language learning. 299 00:12:23,700 --> 00:12:26,140 So that's how these social things and language things 300 00:12:26,140 --> 00:12:28,440 interact very substantially. 301 00:12:28,440 --> 00:12:31,000 And we already said that a 12-month-old will stop at a 302 00:12:31,000 --> 00:12:33,970 visual cliff, but if the mother smiles there they go. 303 00:12:33,970 --> 00:12:36,920 So constant learning that mixes in the 304 00:12:36,920 --> 00:12:39,160 cognitive and the social. 305 00:12:39,160 --> 00:12:42,506 Now the epic name in developmental psychology is 306 00:12:42,506 --> 00:12:43,130 Jean Piaget. 307 00:12:43,130 --> 00:12:46,950 Because prior to him, roughly speaking, in the science of 308 00:12:46,950 --> 00:12:49,880 child development, people just thought children were sort of 309 00:12:49,880 --> 00:12:53,460 boring and dumb. 310 00:12:53,460 --> 00:12:55,310 They need a lot of attention. 311 00:12:55,310 --> 00:13:00,390 Please finish MIT so we can talk with you intelligently. 312 00:13:00,390 --> 00:13:02,130 I guess people were not that interested. 313 00:13:02,130 --> 00:13:04,020 Partly is the world was different in so many ways. 314 00:13:04,020 --> 00:13:06,130 There was no-- practically no-- 315 00:13:06,130 --> 00:13:08,280 formal psychology experimentation or thought 316 00:13:08,280 --> 00:13:11,270 about what really children's mental lives were like. 317 00:13:11,270 --> 00:13:13,501 And Piaget-- 318 00:13:13,501 --> 00:13:17,840 I have a wrong year there, 1886-- 319 00:13:17,840 --> 00:13:19,020 developed-- 320 00:13:19,020 --> 00:13:21,920 he himself was a child prodigy, trained in biology. 321 00:13:21,920 --> 00:13:24,430 Very early interest in whether categories are in our heads or 322 00:13:24,430 --> 00:13:25,540 in the world. 323 00:13:25,540 --> 00:13:26,260 Tried poetry. 324 00:13:26,260 --> 00:13:28,070 Worked with Binet on intelligence testing. 325 00:13:28,070 --> 00:13:30,100 Became interested in patterns of errors and successes. 326 00:13:30,100 --> 00:13:33,510 You'll see that in many ways, what he discovered about how a 327 00:13:33,510 --> 00:13:36,150 child mind is different than yours fundamentally, is based 328 00:13:36,150 --> 00:13:38,470 on the patterns of their errors. 329 00:13:38,470 --> 00:13:40,590 And he said, there's two basic things going on. 330 00:13:40,590 --> 00:13:41,980 This is a huge idea. 331 00:13:41,980 --> 00:13:44,960 One is assimilation, you incorporate new knowledge into 332 00:13:44,960 --> 00:13:46,270 existing cognitive structures. 333 00:13:46,270 --> 00:13:48,790 It's basically ways you think about the world. 334 00:13:48,790 --> 00:13:50,350 And new knowledge is added. 335 00:13:50,350 --> 00:13:51,660 That's important. 336 00:13:51,660 --> 00:13:54,140 But he thought the dramatic thing that happens in infancy 337 00:13:54,140 --> 00:13:56,600 and childhood is what he called adaptation. 338 00:13:56,600 --> 00:13:58,930 That the fundamental ways in which you understand the world 339 00:13:58,930 --> 00:14:01,960 are shifted, through development, to accommodate 340 00:14:01,960 --> 00:14:02,940 new evidence. 341 00:14:02,940 --> 00:14:04,930 So there's a wonderful book if you come across it called The 342 00:14:04,930 --> 00:14:06,940 Scientist in the Crib. 343 00:14:06,940 --> 00:14:08,030 But it's kind of a pun. 344 00:14:08,030 --> 00:14:09,890 It's written by scientists who study infants. 345 00:14:09,890 --> 00:14:13,600 But the idea is that, in a sense, every infant is kind of 346 00:14:13,600 --> 00:14:14,870 his or her own scientist-- 347 00:14:14,870 --> 00:14:15,720 as you were-- 348 00:14:15,720 --> 00:14:18,500 probing the world and discovering the physical and 349 00:14:18,500 --> 00:14:20,390 social laws of the world. 350 00:14:20,390 --> 00:14:22,530 Because they don't know them coming in and they're going to 351 00:14:22,530 --> 00:14:23,750 pick up a lot of them. 352 00:14:23,750 --> 00:14:26,610 They're going to probe them. 353 00:14:26,610 --> 00:14:30,050 But fail to publish the results. 354 00:14:30,050 --> 00:14:33,380 So Piaget postulated that were these big stages, what he 355 00:14:33,380 --> 00:14:36,220 called the Sensorimotor age, zero to two, where the world 356 00:14:36,220 --> 00:14:38,820 is one of what you see and the physical actions. 357 00:14:38,820 --> 00:14:40,920 And there's not much representation of ideas or 358 00:14:40,920 --> 00:14:41,810 lasting thoughts. 359 00:14:41,810 --> 00:14:43,960 And we'll see some examples of these. 360 00:14:43,960 --> 00:14:45,950 Between two and seven, you start to be able to keep a 361 00:14:45,950 --> 00:14:47,160 thought in your mind. 362 00:14:47,160 --> 00:14:48,840 You still have an egocentric prospective. 363 00:14:48,840 --> 00:14:51,720 You see the world from your view but not appreciating the 364 00:14:51,720 --> 00:14:53,770 views of somebody else. 365 00:14:53,770 --> 00:14:55,800 You start to use language. 366 00:14:55,800 --> 00:14:59,430 A lot of flimsy discussion about fantasy and reality. 367 00:14:59,430 --> 00:15:01,340 I could tell you with my own daughter, who you'll meet, 368 00:15:01,340 --> 00:15:02,660 she's still working out whether fairies 369 00:15:02,660 --> 00:15:05,530 really exist or not. 370 00:15:05,530 --> 00:15:07,700 This was chaotic because we went to some skating show 371 00:15:07,700 --> 00:15:11,720 where Tinkerbell was a human dancing, and that totally made 372 00:15:11,720 --> 00:15:12,970 the situation very complicated. 373 00:15:15,430 --> 00:15:16,680 She's still working on that. 374 00:15:16,680 --> 00:15:20,920 Concrete, as you get 7 to 11, organize logical thought. 375 00:15:20,920 --> 00:15:23,420 Still concrete, as opposed to sort of abstract. 376 00:15:23,420 --> 00:15:26,080 And then you move to more adult like cognition, which 377 00:15:26,080 --> 00:15:28,270 we'll talk about next week. 378 00:15:28,270 --> 00:15:33,060 So the idea is from birth to two years, you would love to 379 00:15:33,060 --> 00:15:35,830 have an infant just tell you what do I think the world is 380 00:15:35,830 --> 00:15:36,360 really like. 381 00:15:36,360 --> 00:15:38,800 They have very modest language, of course, so they 382 00:15:38,800 --> 00:15:40,390 can't tell you what they see. 383 00:15:40,390 --> 00:15:43,630 So the thought is they have fleeting, disconnected sensory 384 00:15:43,630 --> 00:15:45,030 impressions and motor reactions. 385 00:15:45,030 --> 00:15:46,270 It's all, what do I see? 386 00:15:46,270 --> 00:15:48,160 How am I responding? 387 00:15:48,160 --> 00:15:52,500 That their focus of thought is centered on actions, not 388 00:15:52,500 --> 00:15:53,990 things or intentions. 389 00:15:53,990 --> 00:15:56,190 And I'll show you in a very concrete way. 390 00:15:56,190 --> 00:15:58,170 That there's no distinction in their mind between things that 391 00:15:58,170 --> 00:16:00,680 are stable in the world and transient events. 392 00:16:00,680 --> 00:16:03,620 No distinction between themselves and the world 393 00:16:03,620 --> 00:16:04,140 around them. 394 00:16:04,140 --> 00:16:09,150 It's all just one big mush until they connect abstract 395 00:16:09,150 --> 00:16:12,650 representations that separate these things out. 396 00:16:12,650 --> 00:16:18,700 So let's talk about object permanence. 397 00:16:18,700 --> 00:16:22,160 I'm going to show you that you have object permanence just by 398 00:16:22,160 --> 00:16:23,940 saying, here's my pointer. 399 00:16:23,940 --> 00:16:24,650 I need a volunteer. 400 00:16:24,650 --> 00:16:31,260 This is so easy that you will not feel scared. 401 00:16:31,260 --> 00:16:34,200 I promise. 402 00:16:34,200 --> 00:16:34,410 All right. 403 00:16:34,410 --> 00:16:35,320 Thank you very much. 404 00:16:35,320 --> 00:16:37,880 So you see this? 405 00:16:37,880 --> 00:16:39,950 Where do you think it is now? 406 00:16:39,950 --> 00:16:41,120 OK. 407 00:16:41,120 --> 00:16:42,740 If I was really cool teacher who did 408 00:16:42,740 --> 00:16:45,690 magic it would be gone. 409 00:16:45,690 --> 00:16:46,870 But yes, and you know it's there. 410 00:16:46,870 --> 00:16:49,070 That's object permanence. 411 00:16:49,070 --> 00:16:50,630 If you turn your head you believe it's 412 00:16:50,630 --> 00:16:52,540 probably still there. 413 00:16:52,540 --> 00:16:56,900 But that's going beyond the fundamentals of perception, 414 00:16:56,900 --> 00:16:58,820 that's your knowledge, and representing in your head, 415 00:16:58,820 --> 00:17:01,350 there's something I don't see but I know it's there. 416 00:17:01,350 --> 00:17:04,980 That is not available to a zero to two year old. 417 00:17:04,980 --> 00:17:09,660 So, for example, if they see a rattle they feel a rattle. 418 00:17:09,660 --> 00:17:12,640 But now if they look away, or if you just put a sheet of 419 00:17:12,640 --> 00:17:13,420 paper in front of it-- 420 00:17:13,420 --> 00:17:15,339 I'll show you a couple of examples-- 421 00:17:15,339 --> 00:17:19,109 they behave as if the rattle no longer exists. 422 00:17:19,109 --> 00:17:20,520 Just like I did in front of you. 423 00:17:20,520 --> 00:17:23,510 If you just cover it up, it's gone as if it doesn't exist. 424 00:17:23,510 --> 00:17:26,579 Because their mind cannot represent what they do not see 425 00:17:26,579 --> 00:17:28,960 right in front of them. 426 00:17:28,960 --> 00:17:32,200 So out of sight out of existence. 427 00:17:32,200 --> 00:17:34,660 So you can show them a toy they love, and until about 428 00:17:34,660 --> 00:17:37,590 eight months, you could do this. 429 00:17:37,590 --> 00:17:38,480 They'll start crying. 430 00:17:38,480 --> 00:17:40,020 They'll protest. 431 00:17:40,020 --> 00:17:42,650 But they won't reach for it, even when it's easily within 432 00:17:42,650 --> 00:17:43,610 their reach. 433 00:17:43,610 --> 00:17:44,730 Out of sight, out of mind. 434 00:17:44,730 --> 00:17:45,330 It doesn't exist. 435 00:17:45,330 --> 00:17:50,560 They can't represent in their mind what they don't see. 436 00:17:50,560 --> 00:17:51,590 And then there's another one. 437 00:17:51,590 --> 00:17:52,990 You'll see a film of this. 438 00:17:52,990 --> 00:17:53,920 But let me tell you this. 439 00:17:53,920 --> 00:17:58,180 Which tells you about actions verses other things. 440 00:17:58,180 --> 00:18:01,400 So imagine you hide a toy under one location, the child 441 00:18:01,400 --> 00:18:02,720 searches there, finds it. 442 00:18:02,720 --> 00:18:04,090 You hide it again in the same location. 443 00:18:04,090 --> 00:18:05,520 You encourage the child to search. 444 00:18:05,520 --> 00:18:06,050 They find it. 445 00:18:06,050 --> 00:18:08,450 They do it two or three times. 446 00:18:08,450 --> 00:18:12,130 Now, in front of the child, you take that same object that 447 00:18:12,130 --> 00:18:13,590 you've shown them like this several times. 448 00:18:13,590 --> 00:18:15,280 They've grabbed several times. 449 00:18:15,280 --> 00:18:17,780 And you simply, in front of them, pick it up 450 00:18:17,780 --> 00:18:19,070 and put it over here. 451 00:18:19,070 --> 00:18:20,510 And they're viewing everything in full view, 452 00:18:20,510 --> 00:18:22,240 just like you did. 453 00:18:22,240 --> 00:18:23,810 What do they do? 454 00:18:23,810 --> 00:18:26,990 When it's their turn to grab they grab here. 455 00:18:26,990 --> 00:18:27,790 The wrong place. 456 00:18:27,790 --> 00:18:29,920 The place where they grab before. 457 00:18:29,920 --> 00:18:33,650 Because what's in their mind is the action they did. 458 00:18:33,650 --> 00:18:36,250 Not the object as an independent thing they can put 459 00:18:36,250 --> 00:18:36,670 in their mind. 460 00:18:36,670 --> 00:18:37,690 Does that makes sense? 461 00:18:37,690 --> 00:18:40,320 And I'll show you several pieces of this. 462 00:18:40,320 --> 00:18:42,120 It's called the A-not-B effect. 463 00:18:42,120 --> 00:18:46,440 I put this A, A, A, A in the front, full view. 464 00:18:46,440 --> 00:18:50,920 Put it over here and they reach over here to get it. 465 00:18:50,920 --> 00:18:56,360 So this is this idea, that in their head is not a toy. 466 00:18:56,360 --> 00:18:58,910 Their head is representing the thing on the right that they 467 00:18:58,910 --> 00:18:59,460 reached for. 468 00:18:59,460 --> 00:19:01,450 Because they don't represent ideas of things. 469 00:19:01,450 --> 00:19:05,610 They represent actions that they've done. 470 00:19:05,610 --> 00:19:07,220 So here's object permanence. 471 00:19:07,220 --> 00:19:10,650 Here's a child sees a toy they like. 472 00:19:10,650 --> 00:19:13,616 You put up, in front of them, this thing and tragically, 473 00:19:13,616 --> 00:19:15,640 it's disappeared. 474 00:19:15,640 --> 00:19:17,190 It's gone out of existence in the world. 475 00:19:21,740 --> 00:19:24,020 Some people have done some sort of NIRS imaging 476 00:19:24,020 --> 00:19:27,990 suggesting that kids who get past this stage are developing 477 00:19:27,990 --> 00:19:29,950 some frontal maturation. 478 00:19:29,950 --> 00:19:31,660 But I think the most compelling things are the 479 00:19:31,660 --> 00:19:32,910 videos of the kids themselves. 480 00:19:38,450 --> 00:19:41,530 So let me show you another film, again very cleverly, the 481 00:19:41,530 --> 00:19:43,880 Renee Baillergon has been one the leaders in this field-- 482 00:19:43,880 --> 00:19:51,520 very cleverly showing you what infants grasp and don't grasp. 483 00:19:51,520 --> 00:19:54,360 Not only the brilliance of these experiments. 484 00:19:54,360 --> 00:19:56,320 These infants are really trying to figure out the 485 00:19:56,320 --> 00:19:58,990 world, and coming up with hypotheses that they're 486 00:19:58,990 --> 00:19:59,580 confirming. 487 00:19:59,580 --> 00:20:02,100 And then when they're broken down they're upset with 488 00:20:02,100 --> 00:20:03,130 what's going on. 489 00:20:03,130 --> 00:20:05,890 So let's move on to age two to seven, especially in the early 490 00:20:05,890 --> 00:20:09,160 years, so-called a preoperational stage. 491 00:20:09,160 --> 00:20:12,100 And one of the coolest things, and we'll try this and see how 492 00:20:12,100 --> 00:20:16,320 it goes with some girls in a few minutes, is this idea. 493 00:20:16,320 --> 00:20:19,130 So if you see two glasses filled with equal amounts of 494 00:20:19,130 --> 00:20:23,070 liquid, and you pour one over into the thinner, taller 495 00:20:23,070 --> 00:20:27,720 glass, c, which will have more water in it? 496 00:20:27,720 --> 00:20:29,930 A or C? 497 00:20:29,930 --> 00:20:31,180 The same. 498 00:20:33,460 --> 00:20:36,650 But not if you're a two year old or a four-year-old. 499 00:20:36,650 --> 00:20:38,700 So it's called conservation of liquid. 500 00:20:45,840 --> 00:20:48,230 So, it's kind of fascinating, isn't it? 501 00:20:48,230 --> 00:20:50,190 It's kind of amazing. 502 00:20:50,190 --> 00:20:52,000 If you do this with a three year old it's virtually 503 00:20:52,000 --> 00:20:53,210 guaranteed they'll do this. 504 00:20:53,210 --> 00:20:55,403 All of you did it all over the world. 505 00:20:55,403 --> 00:20:57,935 And, in some sense, as far as we can guess , all throughout 506 00:20:57,935 --> 00:20:59,220 our species' history. 507 00:20:59,220 --> 00:21:02,660 So brilliant ways of showing that babies, or young 508 00:21:02,660 --> 00:21:06,990 children, really see a little bit of a different world than 509 00:21:06,990 --> 00:21:11,940 you and I as adults. 510 00:21:11,940 --> 00:21:16,080 So here's another very powerful area of research, 511 00:21:16,080 --> 00:21:20,650 which is taking perspectives from the view that other 512 00:21:20,650 --> 00:21:22,810 people have thoughts and feelings besides yourself and 513 00:21:22,810 --> 00:21:24,060 how you interact with them. 514 00:21:26,330 --> 00:21:28,260 And people call this idea theory of mind. 515 00:21:28,260 --> 00:21:32,030 The idea that you understand that other people out there 516 00:21:32,030 --> 00:21:35,360 have their own thoughts, their own feelings distinct from 517 00:21:35,360 --> 00:21:39,040 yours, and in the most challenging case, they can 518 00:21:39,040 --> 00:21:40,990 even be false beliefs. 519 00:21:40,990 --> 00:21:43,580 A person can have wrong information in their head and 520 00:21:43,580 --> 00:21:46,370 truly believe it, even when you know it's wrong. 521 00:21:46,370 --> 00:21:48,520 Because you, as an adult, realize that thoughts are one 522 00:21:48,520 --> 00:21:51,320 thing and physical reality is another thing. 523 00:21:51,320 --> 00:21:52,700 But that's not what children think. 524 00:21:52,700 --> 00:21:55,540 They think there's just one reality. 525 00:21:55,540 --> 00:21:57,670 That's why at the very youngest age, they think if 526 00:21:57,670 --> 00:22:01,970 they cover their eyes that you don't know where they are,. 527 00:22:01,970 --> 00:22:04,220 Because they think there's one physical reality only. 528 00:22:04,220 --> 00:22:06,500 And they don't realize there's another prospective 529 00:22:06,500 --> 00:22:08,080 besides their own. 530 00:22:08,080 --> 00:22:11,250 So here's a very clever experiment showing you that at 531 00:22:11,250 --> 00:22:15,090 three months, children code the word in terms of actions. 532 00:22:15,090 --> 00:22:18,010 And by six to nine months, they begin to understand 533 00:22:18,010 --> 00:22:21,320 intentions, that people out there-- animals too but we'll 534 00:22:21,320 --> 00:22:23,550 just focus on people-- have intentions and 535 00:22:23,550 --> 00:22:25,140 goals in their head. 536 00:22:25,140 --> 00:22:26,900 So here's what the experiment they do using this 537 00:22:26,900 --> 00:22:28,580 habituation. 538 00:22:28,580 --> 00:22:32,460 There's two pedestals here, and a person reaches again and 539 00:22:32,460 --> 00:22:34,960 again for a ball. 540 00:22:34,960 --> 00:22:40,190 So now, what do you believe the intention is? 541 00:22:40,190 --> 00:22:41,630 To reach for the ball. 542 00:22:41,630 --> 00:22:43,790 You see it 10 times, the baby's losing interest. 543 00:22:43,790 --> 00:22:47,470 Now comes their shocker to get the baby crying, or laughing, 544 00:22:47,470 --> 00:22:48,180 or drooling. 545 00:22:48,180 --> 00:22:49,410 Get the baby's attention that you can 546 00:22:49,410 --> 00:22:51,380 measure by how they respond. 547 00:22:51,380 --> 00:22:54,950 And in some conditions, something goes down, and when 548 00:22:54,950 --> 00:22:56,460 it goes back up the person reaches. 549 00:22:56,460 --> 00:22:59,240 But now they take the same action. 550 00:22:59,240 --> 00:23:01,950 They reach for the left pedestal, but 551 00:23:01,950 --> 00:23:03,580 it's a teddy bear. 552 00:23:03,580 --> 00:23:06,380 Or another case, they reach for the ball in 553 00:23:06,380 --> 00:23:08,240 the opposite side. 554 00:23:08,240 --> 00:23:11,780 Who, depending on their age, sees these two different 555 00:23:11,780 --> 00:23:15,300 changes in the scenario as startling? 556 00:23:15,300 --> 00:23:18,750 The three month olds are startled when the person 557 00:23:18,750 --> 00:23:23,150 reaches for the same object. 558 00:23:23,150 --> 00:23:24,350 The three month old. 559 00:23:24,350 --> 00:23:27,270 Because in their mind, the only thing that was really 560 00:23:27,270 --> 00:23:29,960 happening was reach for the left, reach for the left, 561 00:23:29,960 --> 00:23:30,620 reach for the left. 562 00:23:30,620 --> 00:23:32,030 And now you're reaching for the right. 563 00:23:32,030 --> 00:23:34,050 The action changed. 564 00:23:34,050 --> 00:23:36,010 Because the action is independent of intention. 565 00:23:36,010 --> 00:23:38,060 It's just what happened, what happened, what happened. 566 00:23:38,060 --> 00:23:40,080 They're shocked when the person goes for 567 00:23:40,080 --> 00:23:41,510 the ball over here. 568 00:23:41,510 --> 00:23:43,810 By six to nine months, they're shocked-- 569 00:23:43,810 --> 00:23:45,000 relatively speaking-- 570 00:23:45,000 --> 00:23:48,060 when the person reaches for the same action but now the 571 00:23:48,060 --> 00:23:49,260 goal is different. 572 00:23:49,260 --> 00:23:50,660 Grabbing the teddy bear. 573 00:23:50,660 --> 00:23:53,080 It's as if they understand the intention of the person was to 574 00:23:53,080 --> 00:23:55,710 get the ball, and these children think the only thing 575 00:23:55,710 --> 00:23:57,870 that's happening is physical action, physical action, 576 00:23:57,870 --> 00:23:58,890 physical action. 577 00:23:58,890 --> 00:24:01,950 So very clever experiment by this habituation and looking 578 00:24:01,950 --> 00:24:05,660 time to show at three months all you see is actions. 579 00:24:05,660 --> 00:24:09,260 And by six to nine months you start to grasp that people 580 00:24:09,260 --> 00:24:12,360 have intentions in their head above and beyond their actions 581 00:24:12,360 --> 00:24:14,700 that govern their actions. 582 00:24:14,700 --> 00:24:18,020 So to make it really tricky, there's this very clever 583 00:24:18,020 --> 00:24:20,460 experiment that makes-- 584 00:24:20,460 --> 00:24:22,150 and we'll try it in a few minutes-- 585 00:24:22,150 --> 00:24:22,550 this way. 586 00:24:22,550 --> 00:24:24,950 This so-called Sally-Anne problem because it's been so 587 00:24:24,950 --> 00:24:26,760 widely cited and discussed. 588 00:24:26,760 --> 00:24:28,880 So you tell a child this story. 589 00:24:28,880 --> 00:24:31,210 Imagine there's two girls here, Sally and Anne. 590 00:24:31,210 --> 00:24:35,300 And Sally takes a ball and puts it in this basket. 591 00:24:35,300 --> 00:24:37,570 And then she leaves the room. 592 00:24:37,570 --> 00:24:40,910 Anne, who's a little bit of a troublemaker takes the ball 593 00:24:40,910 --> 00:24:44,730 out of here and puts it into this box, and closes the box. 594 00:24:44,730 --> 00:24:47,100 Here's the big question. 595 00:24:47,100 --> 00:24:50,030 When Sally comes back and looks for this ball, where 596 00:24:50,030 --> 00:24:51,060 will she look? 597 00:24:51,060 --> 00:24:53,860 And a three year old says, in the box. 598 00:24:53,860 --> 00:24:56,770 Now if she was out of the room there's no way for her to look 599 00:24:56,770 --> 00:24:57,500 that's in the box. 600 00:24:57,500 --> 00:24:59,750 But for the three year old, there's not 601 00:24:59,750 --> 00:25:01,090 thoughts and reality. 602 00:25:01,090 --> 00:25:03,220 There's just kind of reality. 603 00:25:03,220 --> 00:25:04,520 Does that make sense? 604 00:25:04,520 --> 00:25:07,410 The three year old can't entertain the idea that Sally 605 00:25:07,410 --> 00:25:10,770 has, in her head, wrong knowledge of 606 00:25:10,770 --> 00:25:11,580 where this ball is. 607 00:25:11,580 --> 00:25:13,370 The she couldn't have known where it is and she's going to 608 00:25:13,370 --> 00:25:15,070 act on the knowledge that's in her head. 609 00:25:15,070 --> 00:25:17,300 That's the content of her mind. 610 00:25:17,300 --> 00:25:19,395 The three year old says there's one reality, the ball 611 00:25:19,395 --> 00:25:20,420 is over here. 612 00:25:20,420 --> 00:25:21,280 I know it. 613 00:25:21,280 --> 00:25:22,160 Everybody knows it. 614 00:25:22,160 --> 00:25:25,170 What else is there to even think about? 615 00:25:25,170 --> 00:25:28,740 But that typical five-year-old will say, Sally will look in 616 00:25:28,740 --> 00:25:29,870 the wrong place. 617 00:25:29,870 --> 00:25:31,840 She'll look in the basket. 618 00:25:31,840 --> 00:25:33,810 She'll look in the wrong place compared to 619 00:25:33,810 --> 00:25:34,650 where the ball is now. 620 00:25:34,650 --> 00:25:35,870 Because she believes it's there. 621 00:25:35,870 --> 00:25:37,390 She has the wrong idea in her head. 622 00:25:37,390 --> 00:25:40,970 That ideas can be independent of physical, observable things 623 00:25:40,970 --> 00:25:43,590 in the world. 624 00:25:43,590 --> 00:25:44,870 This is a universal finding. 625 00:25:44,870 --> 00:25:46,050 I'm going to have to change my settings. 626 00:25:46,050 --> 00:25:46,670 Sorry. 627 00:25:46,670 --> 00:25:48,620 Your handout has this. 628 00:25:48,620 --> 00:25:50,540 In practically every country where they've tested this, 629 00:25:50,540 --> 00:25:52,150 three year olds don't have a theory of mind, 630 00:25:52,150 --> 00:25:54,760 five year olds do. 631 00:25:54,760 --> 00:25:55,660 Turns out-- 632 00:25:55,660 --> 00:25:57,420 and you could take a guess-- 633 00:25:57,420 --> 00:26:02,020 the older sibling you have, the younger you become at 634 00:26:02,020 --> 00:26:04,420 getting a good theory of mind. 635 00:26:04,420 --> 00:26:08,840 Nobody really knows what the answer but what's your guess? 636 00:26:08,840 --> 00:26:10,480 The more siblings you have that are older 637 00:26:10,480 --> 00:26:12,540 than you, the younger-- 638 00:26:12,540 --> 00:26:15,090 by some number of months-- people tend to show that they 639 00:26:15,090 --> 00:26:17,290 can understand that people have all kinds of thoughts and 640 00:26:17,290 --> 00:26:19,150 beliefs in their head. 641 00:26:19,150 --> 00:26:20,290 What's your guess? 642 00:26:20,290 --> 00:26:21,180 Yeah. 643 00:26:21,180 --> 00:26:23,340 AUDIENCE: They have gone through versions of the 644 00:26:23,340 --> 00:26:25,020 Sally-Anne problem themselves. 645 00:26:25,020 --> 00:26:26,980 PROFESSOR: They may have been tortured by their siblings. 646 00:26:26,980 --> 00:26:29,070 But on top of that, the intuition is-- and we don't 647 00:26:29,070 --> 00:26:31,160 really know, this is hard to-- 648 00:26:31,160 --> 00:26:33,210 they're living in a world, because they have older 649 00:26:33,210 --> 00:26:35,910 siblings who do unkind things to them, who have superior 650 00:26:35,910 --> 00:26:40,880 powers over them physically, they're much more socially-- 651 00:26:40,880 --> 00:26:42,800 have to figure out what's going on to survive happily 652 00:26:42,800 --> 00:26:45,330 and make their way in the world. 653 00:26:45,330 --> 00:26:48,781 The big five year old, he or she is dominant, and the two 654 00:26:48,781 --> 00:26:50,530 year old is trying to steer around. 655 00:26:50,530 --> 00:26:51,910 Like, what is does that five year old think? 656 00:26:51,910 --> 00:26:53,330 How will I not get into trouble with that 657 00:26:53,330 --> 00:26:56,080 five-year-old and my mother and my father? 658 00:26:56,080 --> 00:27:00,430 A younger sibling has more social pressures to figure out 659 00:27:00,430 --> 00:27:02,430 what's going on and steer your way around, and not get in 660 00:27:02,430 --> 00:27:05,520 trouble with your older siblings. 661 00:27:05,520 --> 00:27:06,400 We'll come back to autism. 662 00:27:06,400 --> 00:27:08,700 I'll just say a word about this now. 663 00:27:08,700 --> 00:27:10,480 You hear a lot about it. 664 00:27:10,480 --> 00:27:13,050 The current guess is that it's approximately 1 out of every 665 00:27:13,050 --> 00:27:14,070 140 children. 666 00:27:14,070 --> 00:27:16,060 A shockinging increase in numbers to what people 667 00:27:16,060 --> 00:27:19,160 believed it was many years ago. 668 00:27:19,160 --> 00:27:21,440 Mysteriously, there's many more boys 669 00:27:21,440 --> 00:27:23,240 than girls with autism. 670 00:27:23,240 --> 00:27:25,790 Estimates are 4 to 1, or 10 to 1 range, all there. 671 00:27:25,790 --> 00:27:27,650 It's hard to know for sure. 672 00:27:27,650 --> 00:27:29,220 We'll talk more about that. 673 00:27:29,220 --> 00:27:31,830 Autism is defined by three things. 674 00:27:31,830 --> 00:27:33,700 A sort of weakness, or deficit, in social 675 00:27:33,700 --> 00:27:35,470 interaction. 676 00:27:35,470 --> 00:27:37,850 Children with autism, or adults, have difficulty in 677 00:27:37,850 --> 00:27:39,270 social interaction. 678 00:27:39,270 --> 00:27:40,220 In communication. 679 00:27:40,220 --> 00:27:43,030 And they have lots of repetitive behaviors that can 680 00:27:43,030 --> 00:27:46,630 be difficult to help in interaction with others. 681 00:27:46,630 --> 00:27:50,130 And when people test theory of mind in children with autism, 682 00:27:50,130 --> 00:27:53,410 it's typically delayed by five or six years on average, for 683 00:27:53,410 --> 00:27:55,420 those children who can take the test at all. 684 00:27:55,420 --> 00:27:59,470 They have a very slowly developing, very delayed 685 00:27:59,470 --> 00:28:01,450 theory of mind and understanding what's in the 686 00:28:01,450 --> 00:28:04,260 content of the thoughts of other people. 687 00:28:04,260 --> 00:28:06,990 And that's considered one of their biggest challenges. 688 00:28:06,990 --> 00:28:08,190 How they relate to other people. 689 00:28:08,190 --> 00:28:10,360 Understanding what the other person's thinking and feeling. 690 00:28:15,470 --> 00:28:17,080 Just for a couple minutes I'm going to show you a video and 691 00:28:17,080 --> 00:28:18,330 then we're going to try-- 692 00:28:18,330 --> 00:28:23,590 So the biggest challenges to Piaget have been this idea 693 00:28:23,590 --> 00:28:26,540 that there's these distinct stages of thought. 694 00:28:26,540 --> 00:28:28,410 That your mind shifts, literally, how it's 695 00:28:28,410 --> 00:28:30,570 constructed and understands the world. 696 00:28:30,570 --> 00:28:33,270 And that people have thought that the process is much more 697 00:28:33,270 --> 00:28:36,300 continuous than Piaget had suggested. 698 00:28:36,300 --> 00:28:39,260 And here's one compelling example of that kind. 699 00:28:39,260 --> 00:28:41,670 So this is the A-not-B experiment. 700 00:28:41,670 --> 00:28:43,490 There's a two food wells, and something of 701 00:28:43,490 --> 00:28:44,540 interest in this infant. 702 00:28:44,540 --> 00:28:48,170 The seven month old looks at the toy here. 703 00:28:48,170 --> 00:28:49,420 It gets covered up. 704 00:28:53,110 --> 00:28:56,500 It's placed in b, and b is one of the two wells. 705 00:28:56,500 --> 00:28:58,990 He continues to look at b when both are covered. 706 00:28:58,990 --> 00:29:01,090 He knows the toy is over there. 707 00:29:01,090 --> 00:29:04,610 And the toy has been placed over and over again in a. 708 00:29:04,610 --> 00:29:06,040 So he gets the A-not-B error. 709 00:29:06,040 --> 00:29:07,750 He has the action. 710 00:29:07,750 --> 00:29:10,170 And even though he sees the toy is placed there. 711 00:29:10,170 --> 00:29:11,050 It's covered up. 712 00:29:11,050 --> 00:29:13,550 He's looking where the toy is. 713 00:29:13,550 --> 00:29:16,750 When it's time to reach he goes to this well. 714 00:29:16,750 --> 00:29:18,510 So this is A-not-B error. 715 00:29:18,510 --> 00:29:25,360 A part of his mind that guides action is stuck and guides 716 00:29:25,360 --> 00:29:27,740 what he reaches for. 717 00:29:27,740 --> 00:29:30,850 But obviously another part of his mind knows perfectly well 718 00:29:30,850 --> 00:29:32,320 where the toy is. 719 00:29:32,320 --> 00:29:36,180 So it's not as if it's all of one, or all of another. 720 00:29:36,180 --> 00:29:39,910 His mind is representing that there's a toy down there, but 721 00:29:39,910 --> 00:29:42,580 the part of his brain or mind that guides his action is 722 00:29:42,580 --> 00:29:44,760 still stuck at this early developmental stage. it's if 723 00:29:44,760 --> 00:29:46,190 he were two ages. 724 00:29:46,190 --> 00:29:48,370 One guiding where his eyes goes. 725 00:29:48,370 --> 00:29:50,070 And one guiding the ultimate action of 726 00:29:50,070 --> 00:29:51,340 where his hands goes. 727 00:29:51,340 --> 00:29:53,960 And as he gets a little older, his eyes and hands will go in 728 00:29:53,960 --> 00:29:56,390 the same place. 729 00:29:56,390 --> 00:29:59,650 OK, last couple of things about how infants are 730 00:29:59,650 --> 00:30:01,300 mathematicians. 731 00:30:01,300 --> 00:30:04,030 Because, of course, we focused on language, or social 732 00:30:04,030 --> 00:30:07,790 thought, but the ideas of counting and, ultimately, 733 00:30:07,790 --> 00:30:11,990 arithmetic or math also come out of children's minds. 734 00:30:11,990 --> 00:30:13,450 And a very clever experiment-- 735 00:30:13,450 --> 00:30:14,640 and I'll show you two of them-- 736 00:30:14,640 --> 00:30:17,840 that shows even at six months, infants are starting to 737 00:30:17,840 --> 00:30:20,130 prepare themselves to become mathematicians. 738 00:30:20,130 --> 00:30:22,010 And here's how they begin the counting. 739 00:30:22,010 --> 00:30:25,480 They're shown displays of three objects or two objects. 740 00:30:25,480 --> 00:30:28,000 And then they hear two sounds like boom boom. 741 00:30:28,000 --> 00:30:29,450 And where do they look? 742 00:30:29,450 --> 00:30:31,560 They tend to look at the one with two objects. 743 00:30:31,560 --> 00:30:32,830 So this is pretty impressive. 744 00:30:32,830 --> 00:30:34,260 They're counting the two. 745 00:30:34,260 --> 00:30:37,340 They're relating something in sound to something in sight 746 00:30:37,340 --> 00:30:40,050 that's arbitrarily related, but that shares the 747 00:30:40,050 --> 00:30:41,690 numerosity. 748 00:30:41,690 --> 00:30:45,030 And if they get boom, boom, boom, three boom sounds, then 749 00:30:45,030 --> 00:30:48,680 they go, OK, now I like the display with three things. 750 00:30:48,680 --> 00:30:52,550 They understand, in some level, twoness and threeness. 751 00:30:52,550 --> 00:30:57,880 And so you start to have the basis of having numbers. 752 00:30:57,880 --> 00:30:59,820 And not only that, Karen Wynn at Yale has shown quite 753 00:30:59,820 --> 00:31:02,300 cleverly, not only do infants have numbers. 754 00:31:02,300 --> 00:31:05,530 They can do a little bit of subtraction and addition. 755 00:31:05,530 --> 00:31:07,190 So here's the experiment she does. 756 00:31:07,190 --> 00:31:08,990 She places an object in a case. 757 00:31:08,990 --> 00:31:10,500 The screen comes up. 758 00:31:10,500 --> 00:31:12,370 Now comes the second object. 759 00:31:12,370 --> 00:31:13,670 And the hand leaves. 760 00:31:13,670 --> 00:31:14,930 OK. 761 00:31:14,930 --> 00:31:15,880 The screen drops. 762 00:31:15,880 --> 00:31:16,680 And there are two. 763 00:31:16,680 --> 00:31:19,120 One plus one equals two. 764 00:31:19,120 --> 00:31:21,520 And the infant goes, OK, no big deal. 765 00:31:21,520 --> 00:31:24,970 But if the screen drops and there's one, the infant is 766 00:31:24,970 --> 00:31:26,790 startled and looks longer. 767 00:31:26,790 --> 00:31:28,130 And they can do it the other way around. 768 00:31:28,130 --> 00:31:30,430 They can do subtraction as well. 769 00:31:30,430 --> 00:31:33,920 So one plus one equals two, and if there's one left by the 770 00:31:33,920 --> 00:31:36,080 trickery of the kind you saw earlier, they're disturbed 771 00:31:36,080 --> 00:31:38,330 that the addition has not occurred correctly. 772 00:31:38,330 --> 00:31:41,290 Or the subtraction has not occurred correctly. 773 00:31:41,290 --> 00:31:45,210 And there's kind of a debate-- this is the last slide-- 774 00:31:45,210 --> 00:31:48,800 and here's the core idea, though, which is this. 775 00:31:48,800 --> 00:31:52,840 That our minds afford us, by evolution, counting up to 776 00:31:52,840 --> 00:31:54,690 about four objects in the world. 777 00:31:54,690 --> 00:31:56,990 And many animals do that as well. 778 00:31:56,990 --> 00:32:00,060 That sort of has to develop a little bit, but we've at lot 779 00:32:00,060 --> 00:32:01,570 running in us. 780 00:32:01,570 --> 00:32:02,970 So that infants can do. 781 00:32:02,970 --> 00:32:06,020 Because, of course, if you show 7-- if you give 77 booms, 782 00:32:06,020 --> 00:32:09,540 they don't look for the display with 77 versus 78. 783 00:32:09,540 --> 00:32:11,030 They can't do that. 784 00:32:11,030 --> 00:32:14,550 So they can operate in the world of 1 to 3 or 1 to 4. 785 00:32:14,550 --> 00:32:15,790 And then they discovered-- 786 00:32:15,790 --> 00:32:19,350 there's been a series of studies in tribes, that are 787 00:32:19,350 --> 00:32:22,060 relatively isolated in different parts of the world, 788 00:32:22,060 --> 00:32:25,290 where in their language they only have words for 789 00:32:25,290 --> 00:32:26,950 one, two, and three. 790 00:32:26,950 --> 00:32:29,050 And everything after that is really described as 791 00:32:29,050 --> 00:32:30,680 many, or a whole lot. 792 00:32:30,680 --> 00:32:33,155 They don't have words for five and up. 793 00:32:33,155 --> 00:32:35,630 There's no word in their language. 794 00:32:35,630 --> 00:32:38,170 Because they've never needed it, apparently, in the worlds 795 00:32:38,170 --> 00:32:39,240 they live in. 796 00:32:39,240 --> 00:32:41,140 So they go to them and they have them do 797 00:32:41,140 --> 00:32:43,150 little counting tasks. 798 00:32:43,150 --> 00:32:46,130 And as soon as they get beyond about four they get very 799 00:32:46,130 --> 00:32:47,930 inaccurate. 800 00:32:47,930 --> 00:32:51,340 It's as if the mind naturally can represent about four 801 00:32:51,340 --> 00:32:54,660 things in the object world, four things in the counting 802 00:32:54,660 --> 00:32:56,420 world-- maybe because of that-- 803 00:32:56,420 --> 00:32:59,920 and after that everything is a cultural invention of higher 804 00:32:59,920 --> 00:33:01,200 level mathematics. 805 00:33:01,200 --> 00:33:03,020 It builds off one to four. 806 00:33:03,020 --> 00:33:04,830 But you don't have it unless your culture 807 00:33:04,830 --> 00:33:06,030 teaches it to you. 808 00:33:06,030 --> 00:33:09,250 Or your culture invents it. 809 00:33:09,250 --> 00:33:11,460 And there's been brain imaging studies too, suggesting that 810 00:33:11,460 --> 00:33:14,570 counting one to four is very different in the brain than 811 00:33:14,570 --> 00:33:17,330 exact mathematics beyond the number four or five. 812 00:33:17,330 --> 00:33:20,940 That's all culturally learned and invented. 813 00:33:20,940 --> 00:33:23,180 It's based on an innate one to four capacity.