1 00:00:00,040 --> 00:00:02,460 The following content is provided under a Creative 2 00:00:02,460 --> 00:00:03,870 Commons license. 3 00:00:03,870 --> 00:00:06,910 Your support will help MIT OpenCourseWare continue to 4 00:00:06,910 --> 00:00:10,560 offer high quality educational resources for free. 5 00:00:10,560 --> 00:00:13,460 To make a donation or view additional materials from 6 00:00:13,460 --> 00:00:19,280 hundreds of MIT courses, visit MIT OpenCourseWare at 7 00:00:19,280 --> 00:00:20,530 ocw.mit.edu. 8 00:00:27,460 --> 00:00:28,710 PROFESSOR: Good afternoon. 9 00:00:33,908 --> 00:00:38,610 So we've come to a topic that I think feels to us like 10 00:00:38,610 --> 00:00:42,870 intuitively almost the core of psychology might be about is 11 00:00:42,870 --> 00:00:43,348 personality. 12 00:00:43,348 --> 00:00:47,172 Why are some things easy for us and hard for us? 13 00:00:47,172 --> 00:00:48,810 Why do we like some things or something else? 14 00:00:48,810 --> 00:00:52,824 Why do people around us behave kindly or rudely, supportively 15 00:00:52,824 --> 00:00:55,184 or loyally or whatever? 16 00:00:55,184 --> 00:00:58,870 What can we understand about personality scientifically? 17 00:00:58,870 --> 00:01:02,382 So how do psychologists try to study it in a somewhat 18 00:01:02,382 --> 00:01:04,379 systematic fashion? 19 00:01:04,379 --> 00:01:07,970 Some key concepts that we're finding are traits, states, 20 00:01:07,970 --> 00:01:09,630 and context. 21 00:01:09,630 --> 00:01:10,180 Traits-- 22 00:01:10,180 --> 00:01:11,170 I'll come to these. 23 00:01:11,170 --> 00:01:14,750 And then finally some brain correlates for personality. 24 00:01:14,750 --> 00:01:17,130 So I love this quote, because I think it's about 25 00:01:17,130 --> 00:01:19,980 individuality, which says, every person is in certain 26 00:01:19,980 --> 00:01:21,930 respects like all other people-- 27 00:01:21,930 --> 00:01:22,780 and we think that's true. 28 00:01:22,780 --> 00:01:27,190 There's something deeply similar among all humans, also 29 00:01:27,190 --> 00:01:29,700 about psychology, also about our brains. 30 00:01:29,700 --> 00:01:32,550 Like some other people, that is, there's dimensions of 31 00:01:32,550 --> 00:01:35,450 individuality, or like some other people, like if we're a 32 00:01:35,450 --> 00:01:38,740 male or female, if we're this age or that age, this culture 33 00:01:38,740 --> 00:01:42,180 or that culture, like math or don't like math, like vanilla 34 00:01:42,180 --> 00:01:44,080 ice cream or don't like ice cream. 35 00:01:44,080 --> 00:01:47,740 And then finally, we come down to the unique set of things 36 00:01:47,740 --> 00:01:49,130 that make you you. 37 00:01:49,130 --> 00:01:51,920 And that's very hard to study, the unique things 38 00:01:51,920 --> 00:01:52,510 that make you you. 39 00:01:52,510 --> 00:01:55,770 But the second level, dimensions of individuality, 40 00:01:55,770 --> 00:01:57,520 we can study in personality. 41 00:01:57,520 --> 00:01:59,480 It's obviously a big one that we feel in our own 42 00:01:59,480 --> 00:02:02,460 lives and around us. 43 00:02:02,460 --> 00:02:08,889 So this is the old original "Star Trek." Like many 44 00:02:08,889 --> 00:02:12,660 programs, or in TV series, it plays out really in part-- 45 00:02:12,660 --> 00:02:15,780 they go from galaxy to galaxy and struggle with various 46 00:02:15,780 --> 00:02:17,330 opponents, civilizations. 47 00:02:17,330 --> 00:02:19,520 But it almost always comes down to a 48 00:02:19,520 --> 00:02:20,820 personality thing, right? 49 00:02:20,820 --> 00:02:23,450 The Captain Kirk who wants to be aggressive and charge in 50 00:02:23,450 --> 00:02:27,300 there and do something very emotional, Spock who's the 51 00:02:27,300 --> 00:02:31,920 pure rational machine, and McCoy who represents a sort of 52 00:02:31,920 --> 00:02:33,930 humane touch, as opposed to the rational thought. 53 00:02:33,930 --> 00:02:36,260 And somewhere in between is the man who has to pick the 54 00:02:36,260 --> 00:02:37,650 action to command the ship, right? 55 00:02:37,650 --> 00:02:40,490 So every show plays out with him asking him 56 00:02:40,490 --> 00:02:41,560 to be human, right? 57 00:02:41,560 --> 00:02:46,060 And him asking him to be rational, and him killing 58 00:02:46,060 --> 00:02:47,690 somebody who's trouble making. 59 00:02:47,690 --> 00:02:49,710 OK. 60 00:02:49,710 --> 00:02:50,860 So what do we mean by personality? 61 00:02:50,860 --> 00:02:52,710 A set of behavioral, emotional, and cognitive 62 00:02:52,710 --> 00:02:54,860 tendencies that people display over time. 63 00:02:54,860 --> 00:02:57,070 When we talk about personality, we really mean 64 00:02:57,070 --> 00:02:59,140 something that we think is consistent in ourselves or in 65 00:02:59,140 --> 00:02:59,750 other people. 66 00:02:59,750 --> 00:03:01,700 It's that somebody is shy, somebody's 67 00:03:01,700 --> 00:03:04,120 helpful, somebody's rude. 68 00:03:04,120 --> 00:03:07,340 And across situations, not just one place, one time, but 69 00:03:07,340 --> 00:03:09,390 pretty regularly. 70 00:03:09,390 --> 00:03:12,130 And that varies across people. 71 00:03:12,130 --> 00:03:14,220 That distinguishes them from one to another. 72 00:03:14,220 --> 00:03:15,880 Something that's kind of-- 73 00:03:15,880 --> 00:03:20,130 there's some similarities, but people vary in this. 74 00:03:20,130 --> 00:03:22,650 And so when people think about this, they think in three 75 00:03:22,650 --> 00:03:23,970 categories as they conceptualize it. 76 00:03:23,970 --> 00:03:24,690 One is traits. 77 00:03:24,690 --> 00:03:29,380 By trait we mean something that's in you that's constant 78 00:03:29,380 --> 00:03:31,610 across situations and times. 79 00:03:31,610 --> 00:03:33,540 But we also think of it as a continuum. 80 00:03:33,540 --> 00:03:36,730 So for example, we talk about introversion/extroversion or 81 00:03:36,730 --> 00:03:39,190 outgoingness and shyness. 82 00:03:39,190 --> 00:03:41,780 It's not that everybody's one or the other. 83 00:03:41,780 --> 00:03:45,850 Along that path from being extremely shy to extremely 84 00:03:45,850 --> 00:03:49,550 outgoing, many of us are somewhere in between. 85 00:03:49,550 --> 00:03:51,550 And then we can talk about states, how we are 86 00:03:51,550 --> 00:03:52,800 temporarily. 87 00:03:52,800 --> 00:03:56,140 How do we feel, excited, afraid, that kind of stuff. 88 00:03:56,140 --> 00:03:59,460 And then situations we're in, because they're specific at 89 00:03:59,460 --> 00:04:01,700 times and places, and that influences us. 90 00:04:01,700 --> 00:04:03,740 We're fearful, we're happy, we're looking forward to 91 00:04:03,740 --> 00:04:05,880 something, we're not looking forward to something. 92 00:04:05,880 --> 00:04:08,870 So these are different pieces that might end up in how we 93 00:04:08,870 --> 00:04:13,600 feel inside and how we act on the world. 94 00:04:13,600 --> 00:04:16,140 So here's a very funny thing, because it's a very different 95 00:04:16,140 --> 00:04:18,140 line of research than practically anything else 96 00:04:18,140 --> 00:04:18,750 that's out there. 97 00:04:18,750 --> 00:04:23,150 Very active, because we're so curious about personality. 98 00:04:23,150 --> 00:04:25,190 Here's how people have basically approached it. 99 00:04:25,190 --> 00:04:28,750 Not everybody, but the main line scientific perspective. 100 00:04:28,750 --> 00:04:31,800 They looked in the dictionary, originally in the 1930s, for 101 00:04:31,800 --> 00:04:34,270 this line of work, and they said, let's look at all the 102 00:04:34,270 --> 00:04:38,420 adjectives in the dictionary that we think might describe 103 00:04:38,420 --> 00:04:42,010 personality in some sense. 104 00:04:42,010 --> 00:04:46,240 They found nearly 18,000 words in the dictionaries that 105 00:04:46,240 --> 00:04:49,420 seemed to be adjectives for describing people, and 106 00:04:49,420 --> 00:04:51,420 something that might be about personality. 107 00:04:51,420 --> 00:04:54,730 Whether you're affable, or amiable, congenial, convivial, 108 00:04:54,730 --> 00:04:56,510 cordial, friendly, genial, sociable, welcoming. 109 00:04:56,510 --> 00:04:59,670 These are all synonyms, right? 110 00:04:59,670 --> 00:05:03,010 They all mean roughly the same thing, we think. 111 00:05:03,010 --> 00:05:07,250 But they found 18,000 terms there because we think a lot 112 00:05:07,250 --> 00:05:09,050 about other people, and talk a lot about other people, and 113 00:05:09,050 --> 00:05:10,870 other people are interesting to us. 114 00:05:10,870 --> 00:05:14,610 And as I said, we're not going to study 18,000 dimensions of 115 00:05:14,610 --> 00:05:16,330 personality, especially when lots of them 116 00:05:16,330 --> 00:05:17,910 overlap like this. 117 00:05:17,910 --> 00:05:21,100 So what we're going to do is see, are there some underlying 118 00:05:21,100 --> 00:05:24,020 traits, a manageable set of personality traits or 119 00:05:24,020 --> 00:05:28,110 dimensions, that many of these 18,000 adjectives sort 120 00:05:28,110 --> 00:05:30,050 of boil down to. 121 00:05:30,050 --> 00:05:33,160 So a manageable set of personality dimensions. 122 00:05:33,160 --> 00:05:35,780 So how do people measure personality in some way? 123 00:05:35,780 --> 00:05:38,380 And for those of us who like to measure things by 124 00:05:38,380 --> 00:05:41,090 behavior-- you do a test, or you push a button, or we 125 00:05:41,090 --> 00:05:42,180 measure your brain-- 126 00:05:42,180 --> 00:05:45,160 personality research is always funny, because the bulk of it 127 00:05:45,160 --> 00:05:48,230 is people's self report about themselves. 128 00:05:48,230 --> 00:05:51,930 And about the last thing most of us in psychology trust is 129 00:05:51,930 --> 00:05:54,050 people's reports about themselves. 130 00:05:54,050 --> 00:05:55,840 And what we think is-- 131 00:05:55,840 --> 00:05:58,260 for many reasons that we can talk about a little bit-- 132 00:05:58,260 --> 00:06:03,010 what we think is that people, when they fill out a piece of 133 00:06:03,010 --> 00:06:05,850 paper describing themselves, they start to have all kinds 134 00:06:05,850 --> 00:06:08,540 of thoughts like, OK, I'm outgoing, but compared to who? 135 00:06:13,230 --> 00:06:15,630 Do I want to fill this out like I really like to think 136 00:06:15,630 --> 00:06:18,500 about myself, or how I think I really am, or am I sometimes 137 00:06:18,500 --> 00:06:20,330 this way and sometimes that way, which 138 00:06:20,330 --> 00:06:21,140 is the right answer. 139 00:06:21,140 --> 00:06:21,560 OK? 140 00:06:21,560 --> 00:06:24,460 So all these things bother us as researchers, but we don't 141 00:06:24,460 --> 00:06:27,020 have a more direct path towards personality. 142 00:06:27,020 --> 00:06:29,490 So we can interview people about their personality. 143 00:06:29,490 --> 00:06:30,300 We can observe-- 144 00:06:30,300 --> 00:06:32,500 I'll talk about some studies that involve observation. 145 00:06:32,500 --> 00:06:35,150 But by far the dominant mode of collecting somewhat 146 00:06:35,150 --> 00:06:37,810 quantitative data about personality are questionnaires 147 00:06:37,810 --> 00:06:39,720 of the kind you just got handed out to you. 148 00:06:39,720 --> 00:06:41,370 Thank you, Tyler. 149 00:06:41,370 --> 00:06:43,750 And the most famous one of all, which you have in your 150 00:06:43,750 --> 00:06:47,310 hands, is the so-called big five personality dimensions. 151 00:06:47,310 --> 00:06:50,400 There's many other aspects of personality-- we'll talk about 152 00:06:50,400 --> 00:06:52,370 that-- but this is the most famous one. 153 00:06:52,370 --> 00:06:55,060 And it was derived in some sense objectively and 154 00:06:55,060 --> 00:06:58,930 empirically from factor analysis like this. 155 00:06:58,930 --> 00:07:01,680 What they said is we have this huge number of terms, but many 156 00:07:01,680 --> 00:07:04,740 of them are either very similar to one another, or 157 00:07:04,740 --> 00:07:06,540 what we might call anti-correlative, they're sort 158 00:07:06,540 --> 00:07:07,650 of opposites. 159 00:07:07,650 --> 00:07:11,680 So for example, if a person is rude, are we also likely to 160 00:07:11,680 --> 00:07:13,520 think of them as kind? 161 00:07:13,520 --> 00:07:14,860 Now you could have-- 162 00:07:14,860 --> 00:07:18,490 there's many movies of the rude senior citizen who turns 163 00:07:18,490 --> 00:07:21,620 out to have a heart of gold underneath, right? 164 00:07:21,620 --> 00:07:24,110 But in general, if you say this person's rude, usually 165 00:07:24,110 --> 00:07:25,990 they'll go, and they're so kind, right? 166 00:07:25,990 --> 00:07:28,680 We think of them as sort of opposites in personality. 167 00:07:28,680 --> 00:07:31,040 If somebody's dependable or carefree. 168 00:07:31,040 --> 00:07:32,730 Now, maybe you know somebody who's both dependable and 169 00:07:32,730 --> 00:07:35,260 carefree, but we tend to think carefree people are not so 170 00:07:35,260 --> 00:07:35,900 dependable. 171 00:07:35,900 --> 00:07:38,280 They can be delightful dependable people. 172 00:07:38,280 --> 00:07:41,840 But now, rude-- you can be dependable and rude or 173 00:07:41,840 --> 00:07:43,560 dependable and polite, right? 174 00:07:43,560 --> 00:07:45,960 OK, so get a feeling of that. 175 00:07:45,960 --> 00:07:50,710 So they have people fill out tons of pieces of paper saying 176 00:07:50,710 --> 00:07:53,790 how do they feel these factors describe them. 177 00:07:53,790 --> 00:07:56,960 And they start out with this huge universe of terms, and 178 00:07:56,960 --> 00:07:59,600 then they try to boil it down, and boil it down, and boil it 179 00:07:59,600 --> 00:08:01,040 down, by looking at-- 180 00:08:01,040 --> 00:08:02,200 Oh, this doesn't show up very well, does it? 181 00:08:02,200 --> 00:08:03,560 Oh, well. 182 00:08:03,560 --> 00:08:04,260 Correlations-- 183 00:08:04,260 --> 00:08:05,640 you have the notes. 184 00:08:05,640 --> 00:08:11,150 So you can guess without being able to see, you can guess-- 185 00:08:11,150 --> 00:08:12,710 let's pick two things. 186 00:08:12,710 --> 00:08:18,900 If I pick the adjectives carefree and dependable, kind 187 00:08:18,900 --> 00:08:21,650 of go together or not go together? 188 00:08:21,650 --> 00:08:24,500 Doesn't tend to go together in people describing themselves. 189 00:08:24,500 --> 00:08:27,940 How about hard working and dependable? 190 00:08:27,940 --> 00:08:30,370 Kind of goes together. 191 00:08:30,370 --> 00:08:33,419 So they said, we can take a lot of these adjectives and 192 00:08:33,419 --> 00:08:36,409 say piles of them go in one area, well, we'll just pick a 193 00:08:36,409 --> 00:08:38,409 few words to describe that dimension. 194 00:08:38,409 --> 00:08:40,400 Piles of them go in another area. 195 00:08:40,400 --> 00:08:46,090 And they boil it down basically by factor analysis, 196 00:08:46,090 --> 00:08:49,800 and they end up with five big factors in this 197 00:08:49,800 --> 00:08:51,260 most widely used one. 198 00:08:51,260 --> 00:08:53,520 So here's two of them. 199 00:08:53,520 --> 00:08:55,440 And here comes a big thing. 200 00:08:55,440 --> 00:08:58,540 They have the factor which is basically just mathematically 201 00:08:58,540 --> 00:09:00,950 a set of adjectives that travel together, that are 202 00:09:00,950 --> 00:09:04,080 highly correlated when people describe themselves. 203 00:09:04,080 --> 00:09:05,855 And they're somewhat anti-correlated or 204 00:09:05,855 --> 00:09:07,470 uncorrelated with the other dimensions. 205 00:09:07,470 --> 00:09:09,950 That's purely empirical. 206 00:09:09,950 --> 00:09:12,380 Now, though, they have the set of adjectives, like carefree 207 00:09:12,380 --> 00:09:16,670 or dependable, not hard-working or hard-working. 208 00:09:16,670 --> 00:09:19,960 Now they have to say, what's the label I'm going to put on 209 00:09:19,960 --> 00:09:22,500 that dimension of human personality? 210 00:09:22,500 --> 00:09:23,700 There's no science for that. 211 00:09:23,700 --> 00:09:24,730 That's judgment. 212 00:09:24,730 --> 00:09:26,220 But five of them get fixed. 213 00:09:26,220 --> 00:09:30,220 And once these got fixed, they've become the terminology 214 00:09:30,220 --> 00:09:31,560 of the field. 215 00:09:31,560 --> 00:09:33,780 So they said, we're going to call one conscientiousness. 216 00:09:33,780 --> 00:09:37,170 Those are people who say they're not carefree, they are 217 00:09:37,170 --> 00:09:38,820 dependable, and they are hard-working. 218 00:09:38,820 --> 00:09:40,810 Does that make sense? 219 00:09:40,810 --> 00:09:42,050 Or somebody's agreeable-- 220 00:09:42,050 --> 00:09:44,440 that's one of the other big five, separate five. 221 00:09:44,440 --> 00:09:47,970 If somebody says, I'm pretty compliant, I'm pretty kind, 222 00:09:47,970 --> 00:09:50,070 and I'm seldom rude. 223 00:09:50,070 --> 00:09:51,840 So I'm going to give you a minute to try this. 224 00:09:51,840 --> 00:09:53,160 You can fill it out fully. 225 00:09:53,160 --> 00:09:56,320 So your piece of paper that you have is a 226 00:09:56,320 --> 00:09:57,910 version of this test. 227 00:09:57,910 --> 00:09:59,110 It's the real thing. 228 00:09:59,110 --> 00:10:00,620 One side tells you how to score it. 229 00:10:00,620 --> 00:10:03,880 Don't look at that, the other side at the bottom. 230 00:10:03,880 --> 00:10:06,430 Just try a few items for fun if you feel like it. 231 00:10:06,430 --> 00:10:12,160 And you can fill it out later and score yourself or print it 232 00:10:12,160 --> 00:10:14,860 out from the notes and score your friends. 233 00:10:14,860 --> 00:10:16,230 Use it responsibly, the knowledge. 234 00:10:20,390 --> 00:10:22,610 And you can just have an intuition of what does it 235 00:10:22,610 --> 00:10:25,370 mean, because almost all personality research, almost 236 00:10:25,370 --> 00:10:27,830 all of it does exactly what you're doing now, which is 237 00:10:27,830 --> 00:10:31,160 gives you a piece of paper, and have you describe yourself 238 00:10:31,160 --> 00:10:32,410 to yourself. 239 00:10:41,160 --> 00:10:42,930 I'll give you a minute just to get a feeling for it. 240 00:10:42,930 --> 00:10:45,880 I think it's kind of fun. 241 00:10:45,880 --> 00:10:47,990 And the feeling you get, like-- 242 00:10:47,990 --> 00:10:49,860 so people worry about stuff, like who are you comparing 243 00:10:49,860 --> 00:10:50,560 yourself to? 244 00:10:50,560 --> 00:10:52,250 If you're outgoing, compared to who? 245 00:10:52,250 --> 00:10:54,000 Compared to Robin Williams, OK? 246 00:10:54,000 --> 00:10:55,560 Maybe not so much. 247 00:10:55,560 --> 00:10:57,290 Compared to your roommate? 248 00:10:57,290 --> 00:10:58,170 Maybe yes. 249 00:10:58,170 --> 00:11:00,520 So all these questions, like where do you get these number 250 00:11:00,520 --> 00:11:03,740 from, how do you come to these answers, and so on. 251 00:11:03,740 --> 00:11:05,670 People worry about polishing your image. 252 00:11:05,670 --> 00:11:08,235 Oh yes, I'm always polite. 253 00:11:08,235 --> 00:11:11,910 I'm nearly perfect when I'm asked to describe myself, OK? 254 00:11:11,910 --> 00:11:13,510 So to the extent that people did that, it 255 00:11:13,510 --> 00:11:14,180 wouldn't work, right? 256 00:11:14,180 --> 00:11:16,200 Because everybody would look perfect all the time. 257 00:11:22,310 --> 00:11:26,640 So these big five are openness, conscientiousness, 258 00:11:26,640 --> 00:11:29,880 extroversion, agreeableness, and neuroticism. 259 00:11:29,880 --> 00:11:33,060 And for memorizing for tests, OCEAN is the acronym. 260 00:11:35,970 --> 00:11:39,790 These were the ones that have come out as five separable 261 00:11:39,790 --> 00:11:42,220 dimensions that seem to cover a tremendous amount of 262 00:11:42,220 --> 00:11:45,620 individual descriptions of human personality, and are 263 00:11:45,620 --> 00:11:46,870 widely used in research. 264 00:11:49,450 --> 00:11:51,635 So here's your big five inventory. 265 00:11:54,670 --> 00:11:56,590 Here's-- 266 00:11:56,590 --> 00:11:59,460 on the backside, how to score it, if you feel like figuring 267 00:11:59,460 --> 00:12:02,900 out what this test would say about yourself, OK? 268 00:12:02,900 --> 00:12:05,740 You could be honest with your scoring, because we're not 269 00:12:05,740 --> 00:12:07,470 going to collect it, it's just you describing you to 270 00:12:07,470 --> 00:12:08,720 yourself, if you're curious. 271 00:12:11,205 --> 00:12:12,370 And now I'm going to go on. 272 00:12:12,370 --> 00:12:14,030 And you're more than welcome to finish it 273 00:12:14,030 --> 00:12:14,640 whenever you want. 274 00:12:14,640 --> 00:12:16,380 It's yours to keep. 275 00:12:16,380 --> 00:12:19,090 And here's how we would score it, or you would score it. 276 00:12:19,090 --> 00:12:21,520 It tells you on the bottom what to do. 277 00:12:21,520 --> 00:12:22,260 For conscientiousness-- 278 00:12:22,260 --> 00:12:23,310 and we'll come back to this, it's a 279 00:12:23,310 --> 00:12:25,180 really interesting measure. 280 00:12:25,180 --> 00:12:26,960 If you rate yourself as somebody who does a thorough 281 00:12:26,960 --> 00:12:29,880 job, is a reliable worker, perseveres until the task is 282 00:12:29,880 --> 00:12:32,620 finished, does things efficiently, and makes plans 283 00:12:32,620 --> 00:12:34,790 and follows through with them. 284 00:12:34,790 --> 00:12:36,650 The higher you rate yourself on those-- this makes sense-- 285 00:12:36,650 --> 00:12:39,300 you're more conscientious, right? 286 00:12:39,300 --> 00:12:43,870 The less you say, that you're somewhat careless, you tend to 287 00:12:43,870 --> 00:12:47,290 be disorganized, you tend to be lazy, and you're easily 288 00:12:47,290 --> 00:12:49,090 distracted, well, those are negative 289 00:12:49,090 --> 00:12:50,530 things for that dimension. 290 00:12:50,530 --> 00:12:51,540 Does that make sense? 291 00:12:51,540 --> 00:12:53,060 So you have to watch when you score it which are the 292 00:12:53,060 --> 00:12:54,980 positive and which are the negative as you score them, 293 00:12:54,980 --> 00:12:56,980 would you get a plus or a minus. 294 00:12:56,980 --> 00:12:59,020 And they try to make it either way, so that if you constantly 295 00:12:59,020 --> 00:13:03,120 say yes, you ought not to score anything that makes 296 00:13:03,120 --> 00:13:04,810 sense, even to yourself. 297 00:13:04,810 --> 00:13:08,760 Anyway, so here's the big questions, right? 298 00:13:08,760 --> 00:13:10,380 All this sort of research behind or this factor 299 00:13:10,380 --> 00:13:12,050 analysis, you'd want to know two things. 300 00:13:12,050 --> 00:13:12,680 Are they stable? 301 00:13:12,680 --> 00:13:15,090 Do they really describe a person across 302 00:13:15,090 --> 00:13:16,750 situations and time? 303 00:13:16,750 --> 00:13:18,420 That's what we mean by personality. 304 00:13:18,420 --> 00:13:21,010 And secondly, do they predict behaviors and life outcomes? 305 00:13:21,010 --> 00:13:23,110 Is there something about them that goes with things that we 306 00:13:23,110 --> 00:13:26,450 care about, variably across people? 307 00:13:26,450 --> 00:13:31,050 So where people have looked at this over some number of 308 00:13:31,050 --> 00:13:34,470 years, it correlates 0.5 to 0.7 across 30 309 00:13:34,470 --> 00:13:36,980 or 40 years of life. 310 00:13:36,980 --> 00:13:40,360 Height and sex, to think about it, correlates 0.4. 311 00:13:40,360 --> 00:13:42,880 Again, height and sex is kind of an-- people will pick that 312 00:13:42,880 --> 00:13:43,480 to think about. 313 00:13:43,480 --> 00:13:46,100 On average, men tend to be taller than women, but lots of 314 00:13:46,100 --> 00:13:49,330 women are taller than lots of individual men, OK? 315 00:13:49,330 --> 00:13:52,530 So it's a stronger relationship across time. 316 00:13:52,530 --> 00:13:54,520 It's more stable than what you'd predict 317 00:13:54,520 --> 00:13:56,180 by height and sex. 318 00:13:56,180 --> 00:13:57,830 And here's something really interesting. 319 00:13:57,830 --> 00:13:59,890 They tested people across seven years-- within 320 00:13:59,890 --> 00:14:03,970 childhood, within young adulthood, within the 30s, and 321 00:14:03,970 --> 00:14:05,220 in the 50 to 70 age range. 322 00:14:05,220 --> 00:14:06,770 And here's something kind of striking. 323 00:14:06,770 --> 00:14:09,930 If you test people twice across seven years, starting 324 00:14:09,930 --> 00:14:14,730 from infancy as best you can-- or questions about them 325 00:14:14,730 --> 00:14:16,980 because they can't fill out forms-- 326 00:14:16,980 --> 00:14:19,970 to adulthood, the striking thing is that the older you 327 00:14:19,970 --> 00:14:22,780 get, the more consistent you become across 328 00:14:22,780 --> 00:14:24,240 a seven year period. 329 00:14:24,240 --> 00:14:27,430 The older you get, the more consistent you become. 330 00:14:27,430 --> 00:14:28,910 So how might you interpret that? 331 00:14:33,070 --> 00:14:34,140 There's a couple different ways you 332 00:14:34,140 --> 00:14:35,750 could think about that. 333 00:14:35,750 --> 00:14:39,990 The older you become, the more consistent you become in 334 00:14:39,990 --> 00:14:41,160 describing your personality-- 335 00:14:41,160 --> 00:14:42,550 let's pretend your descriptions are accurate-- 336 00:14:42,550 --> 00:14:45,940 the more consistent your personality is. 337 00:14:45,940 --> 00:14:47,050 Did you expect that? 338 00:14:47,050 --> 00:14:47,820 Is that what you expect? 339 00:14:47,820 --> 00:14:50,117 Something opposite? 340 00:14:50,117 --> 00:14:51,115 Yeah? 341 00:14:51,115 --> 00:14:53,776 AUDIENCE: They get older, they kind of develop habits and get 342 00:14:53,776 --> 00:14:55,110 set in their ways. 343 00:14:55,110 --> 00:14:55,540 PROFESSOR: Yeah. 344 00:14:55,540 --> 00:14:58,620 So there's two ways to describe getting older. 345 00:14:58,620 --> 00:15:00,880 Like me, I get set in my ways. 346 00:15:00,880 --> 00:15:01,840 Right? 347 00:15:01,840 --> 00:15:03,420 That's OK. 348 00:15:03,420 --> 00:15:06,770 Or I'll say it the other way, we discover the ways that we 349 00:15:06,770 --> 00:15:07,700 really like. 350 00:15:07,700 --> 00:15:09,660 OK? 351 00:15:09,660 --> 00:15:12,620 My friend Robert Sapolsky at Stanford, who writes fantastic 352 00:15:12,620 --> 00:15:15,410 books and who's a fantastic lecturer, had an essay where 353 00:15:15,410 --> 00:15:19,960 he said he noticed in his late 40s or 50s, that the people in 354 00:15:19,960 --> 00:15:24,100 his working lab that they were playing irritating music. 355 00:15:24,100 --> 00:15:25,970 It was just bothering him when they were playing the music. 356 00:15:25,970 --> 00:15:30,390 And it was music that people of your generation listen to. 357 00:15:30,390 --> 00:15:31,450 He said, why is it irritating? 358 00:15:31,450 --> 00:15:33,860 Because when he played his-- 359 00:15:33,860 --> 00:15:35,590 when he played The Beatles or whatever, they were irritating 360 00:15:35,590 --> 00:15:37,050 to his parents, OK. 361 00:15:37,050 --> 00:15:38,440 So what's going on? 362 00:15:38,440 --> 00:15:39,430 And he said, oh. 363 00:15:39,430 --> 00:15:42,440 And so he did a little informal study, he talked to 364 00:15:42,440 --> 00:15:45,230 people of different ages and people in restaurants, they 365 00:15:45,230 --> 00:15:49,020 said, at what age do people seem to stop wanting to do new 366 00:15:49,020 --> 00:15:52,180 things, and get stuck in their ways, or find what they like 367 00:15:52,180 --> 00:15:53,170 and stick with it? 368 00:15:53,170 --> 00:15:54,810 And there's no one answer. 369 00:15:54,810 --> 00:15:57,180 But he found a tremendous number of people, by about 30 370 00:15:57,180 --> 00:16:01,010 to 35, that's their music, they like sushi or they don't 371 00:16:01,010 --> 00:16:03,100 like sushi. 372 00:16:03,100 --> 00:16:05,910 They have their set of stuff that they have going for them 373 00:16:05,910 --> 00:16:06,920 or they don't like. 374 00:16:06,920 --> 00:16:09,500 And so you could say they get stuck in their ways. 375 00:16:09,500 --> 00:16:11,730 You could say they discover what they like 376 00:16:11,730 --> 00:16:12,920 and stick with it. 377 00:16:12,920 --> 00:16:16,260 And here's an age more of exploration and variability. 378 00:16:16,260 --> 00:16:18,150 Who knows? 379 00:16:18,150 --> 00:16:20,200 But it's kind of interesting, the older you get, the more 380 00:16:20,200 --> 00:16:21,962 consistent you get. 381 00:16:21,962 --> 00:16:23,550 Is this flexibility? 382 00:16:23,550 --> 00:16:25,080 Is this chaos? 383 00:16:25,080 --> 00:16:26,220 You could look at it either way. 384 00:16:26,220 --> 00:16:29,020 There's no real answer. 385 00:16:29,020 --> 00:16:31,010 People have looked at these scores and asked whether 386 00:16:31,010 --> 00:16:31,815 things like-- 387 00:16:31,815 --> 00:16:35,010 do they vary with age and gender? 388 00:16:35,010 --> 00:16:41,270 So for example, these broken lines are neuroticism, which 389 00:16:41,270 --> 00:16:42,010 is a funny label. 390 00:16:42,010 --> 00:16:42,970 It really means-- 391 00:16:42,970 --> 00:16:45,830 neuroticism is the bad side of it, stability is the 392 00:16:45,830 --> 00:16:46,490 good side of it. 393 00:16:46,490 --> 00:16:50,650 You could also say too stable could be boring and inert. 394 00:16:50,650 --> 00:16:53,930 You could relabel these things pretty much. 395 00:16:53,930 --> 00:16:58,330 But on average, women's scores are a little bit less stable 396 00:16:58,330 --> 00:17:01,280 than men, a little bit more outgoing, a little bit. 397 00:17:01,280 --> 00:17:03,210 By age, you get a few trends. 398 00:17:03,210 --> 00:17:05,760 This will not surprise you, actually. 399 00:17:05,760 --> 00:17:12,210 So for neuroticism-- again, stability-- 400 00:17:12,210 --> 00:17:14,540 that neuroticism decreases with age. 401 00:17:14,540 --> 00:17:16,640 People get more stable and they get more conscientious as 402 00:17:16,640 --> 00:17:17,140 they get older. 403 00:17:17,140 --> 00:17:18,460 You kind of expect that. 404 00:17:18,460 --> 00:17:21,770 People get more used to their habits and more stuck in their 405 00:17:21,770 --> 00:17:25,829 ways, that we would call stability. 406 00:17:25,829 --> 00:17:29,090 So, let's ask for people who score high or low on these 407 00:17:29,090 --> 00:17:31,330 measures, what do they go with? 408 00:17:31,330 --> 00:17:33,970 So for these five fundamental personality measures. 409 00:17:33,970 --> 00:17:37,010 So people who score highly on the neuroticism scale-- again, 410 00:17:37,010 --> 00:17:38,410 these labels are tricky-- 411 00:17:38,410 --> 00:17:42,100 but it means ranging from very stable and emotional sense to 412 00:17:42,100 --> 00:17:43,680 very labile-- 413 00:17:43,680 --> 00:17:45,790 they pay more attention to threat in the environment, 414 00:17:45,790 --> 00:17:48,280 more stressed when given a surprise math test, have a 415 00:17:48,280 --> 00:17:50,320 higher divorce rate, more susceptible to 416 00:17:50,320 --> 00:17:52,690 depression and anxiety. 417 00:17:52,690 --> 00:17:56,000 At the very, very, very highest scores of neuroticism, 418 00:17:56,000 --> 00:17:59,290 it's a big risk for depression and anxiety. 419 00:17:59,290 --> 00:18:01,900 And one of the deep questions always is, to what extent are 420 00:18:01,900 --> 00:18:06,250 what we call psychiatric labels extremes of personality 421 00:18:06,250 --> 00:18:08,060 or something beyond personality? 422 00:18:08,060 --> 00:18:09,890 This is a much deeper issue than you'd think. 423 00:18:09,890 --> 00:18:11,840 We'll come back to it in psychiatry. 424 00:18:11,840 --> 00:18:14,840 Because some people say there's no such thing, for 425 00:18:14,840 --> 00:18:17,100 example, as social anxiety disorder. 426 00:18:17,100 --> 00:18:18,590 It's a recent invention for what people 427 00:18:18,590 --> 00:18:21,540 used to call shyness. 428 00:18:21,540 --> 00:18:23,540 I don't think that's right, mostly. 429 00:18:23,540 --> 00:18:27,270 But this debate goes on, because there's not a sharp 430 00:18:27,270 --> 00:18:32,410 boundary between being a little shy and so shy that you 431 00:18:32,410 --> 00:18:33,980 don't leave your house to meet people. 432 00:18:33,980 --> 00:18:34,950 That's kind of an extreme. 433 00:18:34,950 --> 00:18:36,330 But most people-- 434 00:18:36,330 --> 00:18:38,890 it's not one person is here and the next person's here, 435 00:18:38,890 --> 00:18:40,380 there's people all along the continuum. 436 00:18:40,380 --> 00:18:44,090 Where you draw the line is a challenging issue. 437 00:18:44,090 --> 00:18:46,370 Highly extroverted people versus highly introverted, 438 00:18:46,370 --> 00:18:48,410 that sort of shyness and outgoingness. 439 00:18:48,410 --> 00:18:49,400 This will be a big surprise. 440 00:18:49,400 --> 00:18:51,930 Highly extroverted people-- by these personality measures-- 441 00:18:51,930 --> 00:18:54,200 attend more parties, they're more popular, they're 442 00:18:54,200 --> 00:18:56,140 identified as leaders in college, they live with and 443 00:18:56,140 --> 00:18:59,380 work with more people, they're less disturbed by sudden loud 444 00:18:59,380 --> 00:19:00,400 sounds or intense stimuli. 445 00:19:00,400 --> 00:19:02,690 You can do experiments in a laboratory and get these 446 00:19:02,690 --> 00:19:03,960 differences. 447 00:19:03,960 --> 00:19:05,080 None of these are sort of surprising. 448 00:19:05,080 --> 00:19:06,260 They're just telling you there's something correct 449 00:19:06,260 --> 00:19:08,110 about these personality measures. 450 00:19:08,110 --> 00:19:11,410 Highly agreeable people are more willing to lend money, 451 00:19:11,410 --> 00:19:12,750 have higher high school grades, and have 452 00:19:12,750 --> 00:19:14,860 fewer arrests as adults. 453 00:19:14,860 --> 00:19:16,760 But the cool thing is not-- 454 00:19:16,760 --> 00:19:17,560 I mean, you're not surprised. 455 00:19:17,560 --> 00:19:19,690 But the fact that they fill out a questionnaire sitting at 456 00:19:19,690 --> 00:19:22,870 a desk like you do, predicts to some decent extent over the 457 00:19:22,870 --> 00:19:24,830 population whether they'll go to jail or not. 458 00:19:24,830 --> 00:19:27,330 That's kind of interesting. 459 00:19:27,330 --> 00:19:28,700 More openness to experience. 460 00:19:28,700 --> 00:19:30,140 You're more likely to major in the humanities-- 461 00:19:33,130 --> 00:19:34,380 not us-- 462 00:19:38,330 --> 00:19:42,040 change careers in midlife, perform better in job training 463 00:19:42,040 --> 00:19:44,810 programs, and play a musical instrument. 464 00:19:44,810 --> 00:19:46,970 But these are massive statistical things. 465 00:19:46,970 --> 00:19:49,630 Because kind of conversely-- 466 00:19:49,630 --> 00:19:53,290 well, you know there's very interesting relations between 467 00:19:53,290 --> 00:19:55,500 musicality and sort of math and science backgrounds. 468 00:19:55,500 --> 00:19:56,900 So that seems to go against this. 469 00:19:56,900 --> 00:19:59,370 So these are big averages. 470 00:19:59,370 --> 00:20:02,860 Maybe, I think, in some ways the most interesting one, for 471 00:20:02,860 --> 00:20:05,930 practical reasons, has turned out to be conscientiousness, 472 00:20:05,930 --> 00:20:08,370 and that's like doing what you're supposed to do. 473 00:20:08,370 --> 00:20:10,830 More sexually faithful to spouses, higher job ratings, 474 00:20:10,830 --> 00:20:13,980 smoke less, drink less, drive more safely, live longer, less 475 00:20:13,980 --> 00:20:16,690 risk for Alzheimer's Disease-- spectacularly less risk. 476 00:20:16,690 --> 00:20:17,800 OK? 477 00:20:17,800 --> 00:20:19,660 And also play a musical instrument? 478 00:20:23,280 --> 00:20:28,620 So the Alzheimer's Disease is kind of interesting, because 479 00:20:28,620 --> 00:20:30,880 what we think is happening-- and we don't really know-- 480 00:20:30,880 --> 00:20:31,220 is this. 481 00:20:31,220 --> 00:20:33,770 So you may know there's basically one gene, now, more 482 00:20:33,770 --> 00:20:35,950 recently, a couple other genes, identified as 483 00:20:35,950 --> 00:20:38,020 significant risk genes for Alzheimer's. 484 00:20:38,020 --> 00:20:40,080 But the one powerful well-identified one is the 485 00:20:40,080 --> 00:20:42,190 so-called APOE gene. 486 00:20:42,190 --> 00:20:43,740 And that is a significant risk gene. 487 00:20:43,740 --> 00:20:48,920 If you're homologous for that, you have a higher risk for 488 00:20:48,920 --> 00:20:50,060 Alzheimer's. 489 00:20:50,060 --> 00:20:52,910 But that best-known, best-characterized gene is a 490 00:20:52,910 --> 00:20:59,100 far smaller risk factor, mathematically, than being low 491 00:20:59,100 --> 00:21:01,180 conscientiousness. 492 00:21:01,180 --> 00:21:03,920 And we don't know what that really means, right? 493 00:21:03,920 --> 00:21:05,460 What's your guess? 494 00:21:05,460 --> 00:21:06,730 And nobody knows. 495 00:21:06,730 --> 00:21:08,280 This is just an empirical finding, and it's been 496 00:21:08,280 --> 00:21:09,400 replicated a number of times. 497 00:21:09,400 --> 00:21:11,900 What's your guess? 498 00:21:11,900 --> 00:21:14,040 So conscientious people do what they're supposed to. 499 00:21:14,040 --> 00:21:15,850 All the things that you're supposed to, in the morning, 500 00:21:15,850 --> 00:21:18,190 get up and do, they do them pretty well. 501 00:21:18,190 --> 00:21:19,440 Right? 502 00:21:21,090 --> 00:21:24,690 Make your bed, do your laundry regularly, brush your teeth 503 00:21:24,690 --> 00:21:28,210 regularly, have your medical appointments regularly, eat 504 00:21:28,210 --> 00:21:30,830 well, exercise, all the things that everybody tells you is 505 00:21:30,830 --> 00:21:32,560 good for you, conscientious people are more 506 00:21:32,560 --> 00:21:33,070 likely to do it. 507 00:21:33,070 --> 00:21:33,890 Yeah? 508 00:21:33,890 --> 00:21:35,360 AUDIENCE: It's sort of an analogy. 509 00:21:35,360 --> 00:21:38,300 The thing is that someone who continuously uses them more-- 510 00:21:38,300 --> 00:21:40,260 more of the pipeline, basically. 511 00:21:40,260 --> 00:21:43,036 Keep water going through them, makes it less likely that it 512 00:21:43,036 --> 00:21:45,160 will clog the pipes-- 513 00:21:45,160 --> 00:21:46,910 PROFESSOR: Yeah, it's something like that. 514 00:21:46,910 --> 00:21:48,060 The pipeline analogy. 515 00:21:48,060 --> 00:21:50,440 If you keep flushing it regularly, instead of clogging 516 00:21:50,440 --> 00:21:53,130 it up with bad things that are bad for you or whatever. 517 00:21:53,130 --> 00:21:55,180 In the end, there has to be a biological mechanism. 518 00:21:55,180 --> 00:21:56,020 In the end, there has to be. 519 00:21:56,020 --> 00:21:58,380 But maybe it's a lifetime of doing healthy things. 520 00:21:58,380 --> 00:22:00,940 And they add up and up, day in, day out, month in, month 521 00:22:00,940 --> 00:22:02,410 out, year in, year out. 522 00:22:02,410 --> 00:22:05,190 That they somehow, in some way, either fend off 523 00:22:05,190 --> 00:22:07,980 Alzheimer's disease or diminish its expression for 524 00:22:07,980 --> 00:22:08,570 much longer. 525 00:22:08,570 --> 00:22:09,690 Does that sound OK? 526 00:22:09,690 --> 00:22:13,170 But it's a very compelling finding. 527 00:22:13,170 --> 00:22:13,400 All right. 528 00:22:13,400 --> 00:22:15,040 So then there's always a fun question up for our 529 00:22:15,040 --> 00:22:16,460 personality, and there will be one big 530 00:22:16,460 --> 00:22:18,570 surprise here, I think. 531 00:22:18,570 --> 00:22:20,325 I'll tell you this is our surprise. 532 00:22:20,325 --> 00:22:22,430 [INAUDIBLE] was reminding me that-- 533 00:22:22,430 --> 00:22:23,940 there's a parents visiting weekend, which 534 00:22:23,940 --> 00:22:25,260 is not today, right? 535 00:22:25,260 --> 00:22:28,160 But a few years ago, I gave this lecture on that, and I 536 00:22:28,160 --> 00:22:31,870 came to a conclusion that parents will find impossible, 537 00:22:31,870 --> 00:22:34,390 untrue, and very disturbing. 538 00:22:34,390 --> 00:22:36,030 Get ready. 539 00:22:36,030 --> 00:22:38,280 Here we go. 540 00:22:38,280 --> 00:22:40,560 Again, we're always curious, our personalities-- 541 00:22:40,560 --> 00:22:42,310 whether we're outgoing or not, agreeable or 542 00:22:42,310 --> 00:22:43,500 not, open or not-- 543 00:22:43,500 --> 00:22:45,560 how much of that is in our genes at birth, how much is 544 00:22:45,560 --> 00:22:48,610 that in our environment in terms of parental influence, 545 00:22:48,610 --> 00:22:51,440 and sibling influence, and school, and so on. 546 00:22:51,440 --> 00:22:54,800 So the usual way to this, until we know the true biology 547 00:22:54,800 --> 00:22:58,110 of this, are estimates from twin studies and children 548 00:22:58,110 --> 00:22:59,430 reared apart and reared separately. 549 00:22:59,430 --> 00:23:01,330 So let me start with the twin studies. 550 00:23:01,330 --> 00:23:06,270 So these are identical twins in green versus dizygotic or 551 00:23:06,270 --> 00:23:08,260 fraternal twins, shared 552 00:23:08,260 --> 00:23:09,910 environment, some shared genes. 553 00:23:09,910 --> 00:23:13,230 The difference about this is thought to be an estimate of 554 00:23:13,230 --> 00:23:15,040 pure genetic heritability. 555 00:23:15,040 --> 00:23:17,030 And say you get a pretty good one-- 556 00:23:17,030 --> 00:23:19,510 extroversion and openness the most, maybe-- 557 00:23:19,510 --> 00:23:26,000 but definitely a genetic contribution to personality. 558 00:23:26,000 --> 00:23:29,390 That's the evidence from twin studies. 559 00:23:29,390 --> 00:23:32,180 And it's even impressive if you do not self report 560 00:23:32,180 --> 00:23:34,160 questionnaires, but behaviors that people describe, 561 00:23:34,160 --> 00:23:35,340 activities they do. 562 00:23:35,340 --> 00:23:37,060 Time spent watching television, number of 563 00:23:37,060 --> 00:23:39,870 childhood accidents, tendency for marriage and divorce, 564 00:23:39,870 --> 00:23:43,230 religious attitudes, your balance between work and 565 00:23:43,230 --> 00:23:46,340 leisure, do you want to be at work all the time or leisure, 566 00:23:46,340 --> 00:23:47,710 or what the balance ought to be. 567 00:23:47,710 --> 00:23:51,820 0.5, that's about half heritable, estimated. 568 00:23:51,820 --> 00:23:52,440 Happiness-- 569 00:23:52,440 --> 00:23:53,760 we'll come back to happiness ratings. 570 00:23:53,760 --> 00:23:57,040 The way people rate happiness, it turns out, is if you do a 571 00:23:57,040 --> 00:23:58,760 one to seven scale, that's the field. 572 00:23:58,760 --> 00:23:59,330 OK? 573 00:23:59,330 --> 00:24:01,310 Seven means happy all the time, one means 574 00:24:01,310 --> 00:24:03,230 miserable all the time. 575 00:24:03,230 --> 00:24:04,710 That's the way happiness research is done. 576 00:24:04,710 --> 00:24:07,140 In the last lecture, we'll talk about what people think 577 00:24:07,140 --> 00:24:10,040 people need to do to be happy. 578 00:24:10,040 --> 00:24:13,150 But one thing we know is that people tend to have happiness 579 00:24:13,150 --> 00:24:13,950 set-points-- 580 00:24:13,950 --> 00:24:16,340 you may know this amongst your friends or yourselves-- 581 00:24:16,340 --> 00:24:19,430 that is, on average, a person will be very happy, or 582 00:24:19,430 --> 00:24:23,110 moderately happy, or pretty grumbly most of the time. 583 00:24:23,110 --> 00:24:23,680 OK? 584 00:24:23,680 --> 00:24:25,530 Something happens in their lives that's really good or 585 00:24:25,530 --> 00:24:27,390 bad, they'll move a little bit, but they'll slide right 586 00:24:27,390 --> 00:24:28,030 back to it. 587 00:24:28,030 --> 00:24:31,070 There's nothing better or worse about one or the other, 588 00:24:31,070 --> 00:24:32,570 but it's just people tend to be pretty set. 589 00:24:32,570 --> 00:24:35,590 And the estimates from twin studies are about half of your 590 00:24:35,590 --> 00:24:39,110 chronic sense of happiness, day in and day out, it comes 591 00:24:39,110 --> 00:24:41,840 from genes, is the estimate. 592 00:24:41,840 --> 00:24:44,320 So that's a big piece. 593 00:24:44,320 --> 00:24:45,760 But here's the kind of stunning thing. 594 00:24:45,760 --> 00:24:47,530 And in the next couple slides I tell you. 595 00:24:47,530 --> 00:24:48,644 Let me tell you the bottom line, let me 596 00:24:48,644 --> 00:24:51,040 tell you the evidence. 597 00:24:51,040 --> 00:24:54,440 The empirical evidence could support a position that 598 00:24:54,440 --> 00:24:58,450 parents and family environments have zero 599 00:24:58,450 --> 00:25:01,490 influence on your personality. 600 00:25:01,490 --> 00:25:04,400 Then the question is, what is the environmental influence? 601 00:25:04,400 --> 00:25:06,270 Because we know it's not all genetic. 602 00:25:06,270 --> 00:25:10,320 But wherever it's been looked at carefully, parents and home 603 00:25:10,320 --> 00:25:15,270 environments appear to have, as far as they can see, nearly 604 00:25:15,270 --> 00:25:16,820 zero influence on your personality. 605 00:25:16,820 --> 00:25:19,670 Now this is the thing that drives parents crazy. 606 00:25:19,670 --> 00:25:21,780 Because as a parent, I can tell you, from the moment 607 00:25:21,780 --> 00:25:24,010 they're born, or even months before children are born, to 608 00:25:24,010 --> 00:25:26,560 the moment you're no longer around to take care of your 609 00:25:26,560 --> 00:25:29,410 children, you want them to develop the right kind of-- 610 00:25:29,410 --> 00:25:31,620 be a happy person, a good person. 611 00:25:31,620 --> 00:25:34,230 Hopefully something about conscientiousness, do well in 612 00:25:34,230 --> 00:25:35,340 life, right? 613 00:25:35,340 --> 00:25:37,480 And you're doing every little thing to encourage that. 614 00:25:37,480 --> 00:25:40,170 The comments you make, the schools you send them to, the 615 00:25:40,170 --> 00:25:42,940 activities you encourage them to do, you want them to have a 616 00:25:42,940 --> 00:25:45,750 personality that will be happy for them and good for them and 617 00:25:45,750 --> 00:25:47,190 thriving, right? 618 00:25:47,190 --> 00:25:51,180 So to be told that whatever you do doesn't matter is kind 619 00:25:51,180 --> 00:25:52,200 of a big shock. 620 00:25:52,200 --> 00:25:53,990 And we don't really know the depth of this. 621 00:25:53,990 --> 00:25:55,420 And it sounds like it's ridiculous. 622 00:25:55,420 --> 00:25:57,090 But I can tell you the empirical evidence kind of 623 00:25:57,090 --> 00:25:58,390 supports it. 624 00:25:58,390 --> 00:26:02,350 So for example, for the twin studies, it makes no 625 00:26:02,350 --> 00:26:04,940 difference at all for personality dimensions whether 626 00:26:04,940 --> 00:26:09,030 twins are raised together or raised apart. 627 00:26:09,030 --> 00:26:11,650 So they're in different families or the same family-- 628 00:26:11,650 --> 00:26:12,550 doesn't make a difference. 629 00:26:12,550 --> 00:26:14,600 All the heritable estimates remain exactly the same. 630 00:26:14,600 --> 00:26:18,080 So where are the environmental factors coming from? 631 00:26:18,080 --> 00:26:19,840 We believe there's environmental factors, but we 632 00:26:19,840 --> 00:26:21,760 can't spot them. 633 00:26:21,760 --> 00:26:24,805 And what's fascinating about these things is that we as 634 00:26:24,805 --> 00:26:27,010 human beings-- and this is just an example now-- 635 00:26:27,010 --> 00:26:31,060 always want to understand who we are as some sort of willful 636 00:26:31,060 --> 00:26:34,150 response to our environment. 637 00:26:34,150 --> 00:26:38,450 So here are two identical twins reared apart. 638 00:26:38,450 --> 00:26:40,760 And they're both super neat. 639 00:26:40,760 --> 00:26:42,270 OK? 640 00:26:42,270 --> 00:26:46,210 And neither one of them tells you, well, it's in my genes, 641 00:26:46,210 --> 00:26:47,320 what else was I going to do? 642 00:26:47,320 --> 00:26:49,520 None of us mostly think that. 643 00:26:49,520 --> 00:26:52,600 Outside of some dire circumstances or diseases, we 644 00:26:52,600 --> 00:26:55,860 mostly think, it's my choice this morning whether I'm going 645 00:26:55,860 --> 00:26:56,830 to make my bed or not. 646 00:26:56,830 --> 00:27:00,020 It's my choice if I do laundry this year or not. 647 00:27:00,020 --> 00:27:01,206 Yeah. 648 00:27:01,206 --> 00:27:05,400 AUDIENCE: Could that other 50% come from things part of the 649 00:27:05,400 --> 00:27:07,060 environment like diet or health? 650 00:27:07,060 --> 00:27:09,290 PROFESSOR: Could the other 50% come from things like diet or 651 00:27:09,290 --> 00:27:10,280 other things in the environment? 652 00:27:10,280 --> 00:27:13,400 It could. 653 00:27:13,400 --> 00:27:16,850 But even that tends to go by families some. 654 00:27:16,850 --> 00:27:19,720 Some families just say, here's a few years worth of potato 655 00:27:19,720 --> 00:27:21,230 chips, good luck. 656 00:27:21,230 --> 00:27:23,370 Another family's going, oh my gosh, you didn't eat carrots 657 00:27:23,370 --> 00:27:25,500 all month long. 658 00:27:25,500 --> 00:27:27,960 Even that tends to be, on average, someone 659 00:27:27,960 --> 00:27:28,880 environmental, right? 660 00:27:28,880 --> 00:27:31,310 Both by economic opportunity, part of the world you're in, 661 00:27:31,310 --> 00:27:32,950 parental attitudes, right? 662 00:27:32,950 --> 00:27:33,550 I agree with you. 663 00:27:33,550 --> 00:27:34,450 It's got to be something. 664 00:27:34,450 --> 00:27:37,620 And maybe we just don't have the whole story right. 665 00:27:37,620 --> 00:27:40,210 But here's two twins telling you why each of 666 00:27:40,210 --> 00:27:41,720 them is very neat. 667 00:27:41,720 --> 00:27:43,230 OK? 668 00:27:43,230 --> 00:27:44,250 The first one is, my mother. 669 00:27:44,250 --> 00:27:47,720 When I was growing up-- this is one household, one twin-- 670 00:27:47,720 --> 00:27:49,890 she always kept the house perfectly ordered. 671 00:27:49,890 --> 00:27:50,950 I learned from her. 672 00:27:50,950 --> 00:27:52,730 What else could I do? 673 00:27:52,730 --> 00:27:54,730 I had a model in my parent. 674 00:27:54,730 --> 00:27:56,000 She was neat, I'm neat. 675 00:27:56,000 --> 00:27:58,180 Here's the other twin, who is also very neat. 676 00:27:58,180 --> 00:27:59,080 The reason is quite simple. 677 00:27:59,080 --> 00:28:01,420 I'm reacting to my mother, who was a complete slob. 678 00:28:01,420 --> 00:28:01,990 OK? 679 00:28:01,990 --> 00:28:03,850 So they're complete opposite stories. 680 00:28:03,850 --> 00:28:05,370 I'm modeling my parents. 681 00:28:05,370 --> 00:28:07,960 I'm rebelling against my parents. 682 00:28:07,960 --> 00:28:10,510 But you know that they're identical twins, and they end 683 00:28:10,510 --> 00:28:11,550 up in the same place. 684 00:28:11,550 --> 00:28:12,433 Yeah? 685 00:28:12,433 --> 00:28:13,683 AUDIENCE: [INAUDIBLE] 686 00:28:25,000 --> 00:28:25,920 PROFESSOR: That's another interpretation. 687 00:28:25,920 --> 00:28:27,000 This is a good question. 688 00:28:27,000 --> 00:28:29,120 The question is, I'm pretending the explanations 689 00:28:29,120 --> 00:28:30,630 have nothing to do with anything, and you're saying 690 00:28:30,630 --> 00:28:31,700 maybe this a personality thing. 691 00:28:31,700 --> 00:28:34,990 Somebody who chooses to model their parent or just somebody 692 00:28:34,990 --> 00:28:36,400 who chooses to rebel against their parent. 693 00:28:36,400 --> 00:28:38,520 Maybe that's the personally dimension, right? 694 00:28:38,520 --> 00:28:39,770 It could be. 695 00:28:41,670 --> 00:28:43,810 It's just neatness. 696 00:28:43,810 --> 00:28:46,010 Twins who aren't neat tend to go the same way and twins who 697 00:28:46,010 --> 00:28:47,060 are neat tend to go the same way. 698 00:28:47,060 --> 00:28:49,640 About 50 percent of the effect is in the genes. 699 00:28:49,640 --> 00:28:50,350 I don't know. 700 00:28:50,350 --> 00:28:51,650 I'm not saying that things aren't there. 701 00:28:51,650 --> 00:28:55,430 It's a bit of a mystery, it's a bit of a shock. 702 00:28:55,430 --> 00:28:57,080 So here's a couple more things. 703 00:28:57,080 --> 00:28:59,050 Biological, non-twin siblings-- 704 00:28:59,050 --> 00:29:02,310 OK, so these are siblings but they're not twins-- 705 00:29:02,310 --> 00:29:04,310 are far more similar to one another 706 00:29:04,310 --> 00:29:05,940 then adoptive siblings. 707 00:29:05,940 --> 00:29:06,500 OK. 708 00:29:06,500 --> 00:29:06,930 That's OK. 709 00:29:06,930 --> 00:29:09,140 That's the genetics, right? 710 00:29:09,140 --> 00:29:10,860 Because the adopted child is into the family. 711 00:29:10,860 --> 00:29:12,390 But here's a shocking one. 712 00:29:12,390 --> 00:29:15,110 For personality, children are no more similar to an adoptive 713 00:29:15,110 --> 00:29:18,710 sibling than are two randomly selected children. 714 00:29:18,710 --> 00:29:22,120 So in a household, if you have an adopted child and a 715 00:29:22,120 --> 00:29:24,410 biological child in that household, sharing the same 716 00:29:24,410 --> 00:29:27,830 environment, they are no more similar, one to the other, 717 00:29:27,830 --> 00:29:31,350 than two random children in the world. 718 00:29:31,350 --> 00:29:34,820 OK, where is the effect of the environment? 719 00:29:34,820 --> 00:29:37,550 Where is the parental effect on the two children in terms 720 00:29:37,550 --> 00:29:39,240 of personality? 721 00:29:39,240 --> 00:29:42,210 So people have mounted this argument. 722 00:29:42,210 --> 00:29:43,800 So let me pick another one. 723 00:29:43,800 --> 00:29:45,070 Put up your hand if you want to. 724 00:29:45,070 --> 00:29:46,060 I'll put up my hand. 725 00:29:46,060 --> 00:29:49,540 How many people grew up in a household where one or more 726 00:29:49,540 --> 00:29:52,310 parents spoke in a noticeable accent? 727 00:29:52,310 --> 00:29:53,340 I mean, I did. 728 00:29:53,340 --> 00:29:55,350 Let's just try this here. 729 00:29:55,350 --> 00:29:58,440 How many of you who have your hand up-- keep your hand up-- 730 00:29:58,440 --> 00:30:02,380 did you keep your parents' accent? 731 00:30:02,380 --> 00:30:05,460 Where's the environment? 732 00:30:05,460 --> 00:30:08,970 In your critical moments of language development, you were 733 00:30:08,970 --> 00:30:10,730 hearing that accent. 734 00:30:10,730 --> 00:30:12,420 Where is the environment? 735 00:30:12,420 --> 00:30:13,850 And you could say, well, yeah, but there are other people 736 00:30:13,850 --> 00:30:14,550 speaking other things. 737 00:30:14,550 --> 00:30:18,260 Yeah, but then zero parental influence on the way in which 738 00:30:18,260 --> 00:30:19,520 you produce your language. 739 00:30:19,520 --> 00:30:21,840 So there's a lot of different things to think as we move 740 00:30:21,840 --> 00:30:24,700 from language to personality, but it's turning out to be 741 00:30:24,700 --> 00:30:26,810 surprisingly hard on some dimensions to show an 742 00:30:26,810 --> 00:30:30,610 influence of parental environment on child 743 00:30:30,610 --> 00:30:31,730 development, especially in personality. 744 00:30:31,730 --> 00:30:32,548 Yeah. 745 00:30:32,548 --> 00:30:35,964 AUDIENCE: So, first off, for the adopted sibling thing. 746 00:30:35,964 --> 00:30:39,380 It seems like that way, not only would they get similar 747 00:30:39,380 --> 00:30:42,308 parental environment, but they also probably have similar 748 00:30:42,308 --> 00:30:43,290 school environment-- 749 00:30:43,290 --> 00:30:43,690 PROFESSOR: Oh, yes. 750 00:30:43,690 --> 00:30:45,710 It's worse than that. 751 00:30:45,710 --> 00:30:46,810 This is a very good question. 752 00:30:46,810 --> 00:30:49,120 It's not only that they have adoptive parents, if they have 753 00:30:49,120 --> 00:30:50,780 another kid in the house, there's another kid in the 754 00:30:50,780 --> 00:30:53,590 house, they probably go to the same-- if they go to church or 755 00:30:53,590 --> 00:30:57,150 synagogue or anything like that. 756 00:30:57,150 --> 00:31:02,680 Same school, same state, same influence of whoever's the NBA 757 00:31:02,680 --> 00:31:04,870 basketball champion. 758 00:31:04,870 --> 00:31:05,770 The whole list. 759 00:31:05,770 --> 00:31:07,290 And it seems to be-- 760 00:31:07,290 --> 00:31:09,206 you can't identify anything in that. 761 00:31:09,206 --> 00:31:10,870 Yeah? 762 00:31:10,870 --> 00:31:16,226 AUDIENCE: Something that is biological but not in DNA, 763 00:31:16,226 --> 00:31:17,710 that is also 50-50? 764 00:31:17,710 --> 00:31:18,260 PROFESSOR: Yeah. 765 00:31:18,260 --> 00:31:20,330 So diet would influence that. 766 00:31:20,330 --> 00:31:22,782 Who knows? 767 00:31:22,782 --> 00:31:24,856 AUDIENCE: Stuff like you're born with, so that it's not 768 00:31:24,856 --> 00:31:27,662 just as an environmental thing, but it's not, strictly 769 00:31:27,662 --> 00:31:29,630 speaking, in your DNA. 770 00:31:29,630 --> 00:31:32,150 Because that's what identical twins-- 771 00:31:32,150 --> 00:31:34,630 PROFESSOR: Well, let me stop you there for one moment. 772 00:31:34,630 --> 00:31:37,770 I think at some level of analysis, all environmental 773 00:31:37,770 --> 00:31:38,290 influences-- 774 00:31:38,290 --> 00:31:40,580 education, parenting, everything-- 775 00:31:40,580 --> 00:31:44,410 will have a biological counterpart in your body and 776 00:31:44,410 --> 00:31:46,360 in your brain, right? 777 00:31:46,360 --> 00:31:49,280 Because the environment has to affect you by how it changes 778 00:31:49,280 --> 00:31:51,630 your body or brain. 779 00:31:51,630 --> 00:31:52,540 After you're born. 780 00:31:52,540 --> 00:31:53,310 It could be added in. 781 00:31:53,310 --> 00:31:54,010 There's things-- 782 00:31:54,010 --> 00:31:57,370 methylation, there's a lot-- yeah, it could be all those 783 00:31:57,370 --> 00:32:01,680 things, but who's driving that? 784 00:32:01,680 --> 00:32:03,390 So it's not-- 785 00:32:03,390 --> 00:32:05,370 my bet is that we'll discover stuff about this that 786 00:32:05,370 --> 00:32:07,280 we don't grasp yet. 787 00:32:07,280 --> 00:32:10,600 The answer is not going to be parenting makes no difference, 788 00:32:10,600 --> 00:32:12,580 or environments make no difference, or schools make no 789 00:32:12,580 --> 00:32:15,340 difference, for personality. 790 00:32:15,340 --> 00:32:17,610 But we just don't know how to think about that yet is the 791 00:32:17,610 --> 00:32:19,870 best guess, because it's just hard to believe. 792 00:32:19,870 --> 00:32:20,512 Yeah. 793 00:32:20,512 --> 00:32:23,450 AUDIENCE: Is there a correlation between IQ and any 794 00:32:23,450 --> 00:32:24,580 kind of personality? 795 00:32:24,580 --> 00:32:26,030 PROFESSOR: IQ and personality? 796 00:32:26,030 --> 00:32:27,655 There is a moderate-- 797 00:32:27,655 --> 00:32:29,460 of conscientiousness especially, 798 00:32:29,460 --> 00:32:30,490 but that makes sense. 799 00:32:30,490 --> 00:32:32,110 On average-- 800 00:32:32,110 --> 00:32:35,650 and we certainly know people who are very smart and very 801 00:32:35,650 --> 00:32:39,430 sloppy, but on average, the more conscientious you are, 802 00:32:39,430 --> 00:32:41,580 like if you go to school, you do your homework, that kinds 803 00:32:41,580 --> 00:32:43,385 of stuff, there is a positive correlation. 804 00:32:46,630 --> 00:32:48,640 So there's all kinds of-- one question is how much 805 00:32:48,640 --> 00:32:50,880 personality is fixing your environment. 806 00:32:50,880 --> 00:32:54,100 So how much is the way you are, from the moment you're 807 00:32:54,100 --> 00:32:57,000 born, driving actually the way the teacher responds to you in 808 00:32:57,000 --> 00:32:58,820 school, the way the parent responds to you? 809 00:32:58,820 --> 00:33:01,310 And so that's why your personality's already driving 810 00:33:01,310 --> 00:33:03,760 your actual environment. 811 00:33:03,760 --> 00:33:05,070 Because we could say, well, you're in a school, but 812 00:33:05,070 --> 00:33:06,952 really, do you like the teacher, do you 813 00:33:06,952 --> 00:33:07,810 not like the teacher? 814 00:33:07,810 --> 00:33:09,020 Do you like your parents? 815 00:33:09,020 --> 00:33:09,820 Do you follow them? 816 00:33:09,820 --> 00:33:11,100 Do you oppose them? 817 00:33:11,100 --> 00:33:12,830 Maybe those kinds of things are happening. 818 00:33:12,830 --> 00:33:18,240 Sometimes people think that your personality is driving 819 00:33:18,240 --> 00:33:21,010 the way your environment responds to you. 820 00:33:21,010 --> 00:33:23,480 It might be done by sibling contrast. 821 00:33:23,480 --> 00:33:25,070 So you may have this experience that-- 822 00:33:28,740 --> 00:33:31,990 parents and other people and siblings yourself often think 823 00:33:31,990 --> 00:33:34,140 a fair bit how they are similar or dissimilar from 824 00:33:34,140 --> 00:33:36,570 their own sibling, and they might overdo it. 825 00:33:36,570 --> 00:33:39,410 Because a parent has two kids, one kid's like 1% more 826 00:33:39,410 --> 00:33:43,060 outgoing, and they go, that's the outgoing one. 827 00:33:43,060 --> 00:33:46,380 One kid plays 5% more time on the piano, and they go, oh, 828 00:33:46,380 --> 00:33:47,480 she's the real musician. 829 00:33:47,480 --> 00:33:49,920 And because he plays two more baseball games a year, he's 830 00:33:49,920 --> 00:33:51,020 the athlete. 831 00:33:51,020 --> 00:33:54,580 And then it starts to snowball that way, OK? 832 00:33:54,580 --> 00:33:55,800 Or parent identification. 833 00:33:55,800 --> 00:33:58,060 Could kids who identify with one parent or the other, 834 00:33:58,060 --> 00:34:00,770 again, by their predispositions, sort of be 835 00:34:00,770 --> 00:34:03,500 driving the way their parents interact with them in a way 836 00:34:03,500 --> 00:34:05,130 that's, again, driven by the personality? 837 00:34:05,130 --> 00:34:06,070 The personality-- 838 00:34:06,070 --> 00:34:08,370 from the first moment, for one reason or another-- 839 00:34:08,370 --> 00:34:11,120 is molding the environment around it and carrying the 840 00:34:11,120 --> 00:34:13,179 environmental effect as well. 841 00:34:13,179 --> 00:34:17,310 So one of the giant fights in all of psychology is this. 842 00:34:17,310 --> 00:34:18,435 And there's not going to be an answer, I'll just 843 00:34:18,435 --> 00:34:20,550 tell you the debate. 844 00:34:20,550 --> 00:34:23,020 And it's at the core of this question of why do we do the 845 00:34:23,020 --> 00:34:25,000 things we do. 846 00:34:25,000 --> 00:34:26,949 So personality adjusted psychologists will say, it's 847 00:34:26,949 --> 00:34:28,500 these things we've just discussed. 848 00:34:28,500 --> 00:34:31,179 It's our predispositions to like things and not like other 849 00:34:31,179 --> 00:34:33,880 things in a general way are personality. 850 00:34:33,880 --> 00:34:34,960 Social psychologists-- 851 00:34:34,960 --> 00:34:37,440 and we'll spend two lectures in just a few weeks on social 852 00:34:37,440 --> 00:34:37,969 psychology-- 853 00:34:37,969 --> 00:34:41,730 say people are all kind of the same. 854 00:34:41,730 --> 00:34:45,870 It's all about the social situation we're in. 855 00:34:45,870 --> 00:34:48,350 Probably it's like one of these nature-nurture things. 856 00:34:48,350 --> 00:34:50,270 Probably something about the situation is something about 857 00:34:50,270 --> 00:34:51,969 who you are. 858 00:34:51,969 --> 00:34:56,520 But let me tell you how some of this debate is played out. 859 00:34:56,520 --> 00:35:01,130 So a famous study that went against the idea of a 860 00:35:01,130 --> 00:35:04,890 personality being constant across situations and time 861 00:35:04,890 --> 00:35:06,530 came from Walter Mischel. 862 00:35:06,530 --> 00:35:08,020 And they looked at conscientiousness. 863 00:35:08,020 --> 00:35:10,710 And they said, OK, some kids score high or low or medium on 864 00:35:10,710 --> 00:35:12,140 conscientiousness. 865 00:35:12,140 --> 00:35:16,850 Now, let's look at 19 specific behaviors in their life. 866 00:35:16,850 --> 00:35:19,170 Not their report of how they are, or their parents' report 867 00:35:19,170 --> 00:35:21,590 of how they are, but things they do that we can measure. 868 00:35:21,590 --> 00:35:22,830 How often do they make their bed? 869 00:35:22,830 --> 00:35:24,410 How often do they go to class like they should? 870 00:35:24,410 --> 00:35:26,430 How often do they complete their homework assignments? 871 00:35:26,430 --> 00:35:28,910 How often do they have good class notes 872 00:35:28,910 --> 00:35:29,730 when they leave classes? 873 00:35:29,730 --> 00:35:33,310 So things you can check, yes or no. 874 00:35:33,310 --> 00:35:37,190 And they said gee, what we notice is somebody tends to be 875 00:35:37,190 --> 00:35:39,310 pretty consistent about whether they make their bed or 876 00:35:39,310 --> 00:35:41,020 not every morning-- not perfect, but pretty 877 00:35:41,020 --> 00:35:42,150 consistent. 878 00:35:42,150 --> 00:35:44,900 But that same person may or may not be so good at 879 00:35:44,900 --> 00:35:46,150 completing homework assignments. 880 00:35:48,520 --> 00:35:50,430 And that person that's very consistent on completing 881 00:35:50,430 --> 00:35:52,920 homework assignments may or may not be so good on having 882 00:35:52,920 --> 00:35:55,020 neat class notes. 883 00:35:55,020 --> 00:35:59,590 So it's not that people aren't consistent, but it's far more 884 00:35:59,590 --> 00:36:02,070 specific about what they're consistent about than a big 885 00:36:02,070 --> 00:36:04,910 personality dimension that covers a range of things that 886 00:36:04,910 --> 00:36:05,810 ought to go together. 887 00:36:05,810 --> 00:36:07,150 So this is situationism. 888 00:36:07,150 --> 00:36:10,290 You behave in a certain way in a certain situation. 889 00:36:10,290 --> 00:36:12,200 It's not like you have a personality that moves from 890 00:36:12,200 --> 00:36:16,300 situation to situation and predicts the same behavior. 891 00:36:16,300 --> 00:36:18,310 And here's another example of how they follow kids in a 892 00:36:18,310 --> 00:36:21,890 summer camp, and here's different behaviors from one 893 00:36:21,890 --> 00:36:23,280 child to another child. 894 00:36:23,280 --> 00:36:28,310 So this is a child who, when a peer approaches, how verbally 895 00:36:28,310 --> 00:36:29,600 aggressive they are. 896 00:36:29,600 --> 00:36:31,180 And so, aggression is high this way. 897 00:36:31,180 --> 00:36:32,320 These are different situations. 898 00:36:32,320 --> 00:36:34,160 And you can see for one child they're aggressive in this 899 00:36:34,160 --> 00:36:36,570 situation when they deal with an adult, and in this 900 00:36:36,570 --> 00:36:39,530 situation this other child is aggressive when he or she 901 00:36:39,530 --> 00:36:41,220 deals with a peer. 902 00:36:41,220 --> 00:36:43,880 So if you were to say there's an aggressive thing about 903 00:36:43,880 --> 00:36:45,710 people-- they're aggressive or they're not-- well, this 904 00:36:45,710 --> 00:36:47,890 person's aggressive with a peer, and this person is 905 00:36:47,890 --> 00:36:51,070 aggressive specifically with an adult. 906 00:36:51,070 --> 00:36:53,430 And so is aggressiveness a personality thing? 907 00:36:53,430 --> 00:36:56,430 Or situation by situation by situation? 908 00:36:56,430 --> 00:36:58,100 In the movies you see all the time-- 909 00:36:58,100 --> 00:37:01,920 if you watch The Sopranos or many movies, it's not uncommon 910 00:37:01,920 --> 00:37:05,590 to have the crime figure be really kind of nice with his 911 00:37:05,590 --> 00:37:10,450 family, and really brutal with a competing criminal gang. 912 00:37:10,450 --> 00:37:10,600 Right? 913 00:37:10,600 --> 00:37:13,350 Have you seen that? 914 00:37:13,350 --> 00:37:15,330 They're kind of nice at home, and then they go shoot people 915 00:37:15,330 --> 00:37:17,350 on two seconds notice if they're 916 00:37:17,350 --> 00:37:18,220 fighting about something. 917 00:37:18,220 --> 00:37:20,700 So you see that kind of an idea. 918 00:37:24,010 --> 00:37:27,510 Another thing that people have looked at that's related to 919 00:37:27,510 --> 00:37:28,760 personality is temperament. 920 00:37:31,560 --> 00:37:33,190 So it's an innate, biologically based propensity 921 00:37:33,190 --> 00:37:34,900 to engage in a certain style of behavior. 922 00:37:34,900 --> 00:37:36,050 It's broader than a trait. 923 00:37:36,050 --> 00:37:39,230 I'll describe one that's been well studied, but people like 924 00:37:39,230 --> 00:37:40,540 it because they think it's observable. 925 00:37:40,540 --> 00:37:43,720 So with traits, it's hard to just look at you and say 926 00:37:43,720 --> 00:37:46,430 you're extroverted or you're conscientious. 927 00:37:46,430 --> 00:37:48,020 I could follow you around all day and 928 00:37:48,020 --> 00:37:49,690 maybe have an estimate. 929 00:37:49,690 --> 00:37:52,830 But here, temperaments are broader than traits, and you 930 00:37:52,830 --> 00:37:56,050 can see it in terms of people's sociability, 931 00:37:56,050 --> 00:37:57,680 emotionality and activity level. 932 00:37:57,680 --> 00:37:59,460 You can just follow them and see them 933 00:37:59,460 --> 00:38:01,260 behave in certain ways. 934 00:38:01,260 --> 00:38:03,910 So let's think about the temperament of shyness. 935 00:38:03,910 --> 00:38:06,350 So the way these studies were done at Harvard was that some 936 00:38:06,350 --> 00:38:08,240 babies, even at six weeks, are more reactive 937 00:38:08,240 --> 00:38:09,150 to make sudden noises. 938 00:38:09,150 --> 00:38:10,410 They're more fussy. 939 00:38:10,410 --> 00:38:12,620 About 20% of children could be that way. 940 00:38:12,620 --> 00:38:14,925 They make a noise or something and they cry, they get 941 00:38:14,925 --> 00:38:16,650 disturbed, they're unhappy. 942 00:38:16,650 --> 00:38:19,870 And so he called those children high-reactive or 943 00:38:19,870 --> 00:38:21,610 inhibited babies. 944 00:38:21,610 --> 00:38:23,120 They use those two terms for the same 945 00:38:23,120 --> 00:38:24,540 idea, versus low reactive. 946 00:38:24,540 --> 00:38:26,770 Ones who were very disturbed by the environment, and ones 947 00:38:26,770 --> 00:38:29,800 who were, like, no big deal. 948 00:38:29,800 --> 00:38:32,770 And the ones who were inhibited babies cried more, 949 00:38:32,770 --> 00:38:34,870 they were distressed more, they showed more activity, 950 00:38:34,870 --> 00:38:38,110 faster heart rates, higher levels of cortisol. 951 00:38:38,110 --> 00:38:39,720 And they even have-- they could measure this in some 952 00:38:39,720 --> 00:38:41,440 cases-- faster heart rates in the womb, even 953 00:38:41,440 --> 00:38:42,790 before they were born. 954 00:38:42,790 --> 00:38:43,820 Their hearts were racing. 955 00:38:43,820 --> 00:38:45,750 So all they'd need is that one last little thing. 956 00:38:45,750 --> 00:38:47,680 And the idea is that maybe their sympathetic nervous 957 00:38:47,680 --> 00:38:50,360 system is easily aroused, seeks less arousing 958 00:38:50,360 --> 00:38:53,170 situations, and it's inhibited because they're already 959 00:38:53,170 --> 00:38:56,700 internally so aroused, they want calm. 960 00:38:56,700 --> 00:38:59,200 So there's going to be a surprise in this story. 961 00:38:59,200 --> 00:39:02,830 But as you go, in terms of thinking about shyness, and 962 00:39:02,830 --> 00:39:04,780 you can measure these at two months or four months with 963 00:39:04,780 --> 00:39:06,660 these very simple little things you do with babies to 964 00:39:06,660 --> 00:39:09,020 see how they respond to some noise. 965 00:39:09,020 --> 00:39:11,580 And to a decent extent, it predicts shyness in later 966 00:39:11,580 --> 00:39:13,140 childhood and adulthood. 967 00:39:13,140 --> 00:39:15,780 About a quarter of the children who look pretty 968 00:39:15,780 --> 00:39:19,990 inhibited aren't shy, but about 75% who look pretty 969 00:39:19,990 --> 00:39:21,480 inhibited end up shy. 970 00:39:21,480 --> 00:39:23,230 So that's a pretty good prediction from a 971 00:39:23,230 --> 00:39:25,290 two-month-old to a young adult. 972 00:39:25,290 --> 00:39:27,330 About 75% of these children who look 973 00:39:27,330 --> 00:39:29,800 pretty shy at two months-- 974 00:39:29,800 --> 00:39:31,440 and of course, they're not shy in a group, they're just 975 00:39:31,440 --> 00:39:32,970 responding to noises-- 976 00:39:32,970 --> 00:39:35,040 end up being kind of shy as adults. 977 00:39:38,740 --> 00:39:44,000 And they studied these until age 21, and again, in several 978 00:39:44,000 --> 00:39:49,530 outcomes, specifically things like-- let's pick one-- 979 00:39:49,530 --> 00:39:51,240 crime, how often they get in crime. 980 00:39:51,240 --> 00:39:54,270 Children who are well controlled don't get so much 981 00:39:54,270 --> 00:39:54,740 into crime. 982 00:39:54,740 --> 00:39:59,410 Children who at 21 had poor control at age three are more 983 00:39:59,410 --> 00:40:00,650 likely to get into trouble. 984 00:40:00,650 --> 00:40:04,130 So as if these temperament factors in early, early 985 00:40:04,130 --> 00:40:07,420 childhood are already risk factors for doing better or 986 00:40:07,420 --> 00:40:10,610 worse in the world. 987 00:40:10,610 --> 00:40:14,320 Another one that people enjoy studying is sensation seeking. 988 00:40:14,320 --> 00:40:17,130 You know, the bungee jumpers, the people who like to 989 00:40:17,130 --> 00:40:20,770 parachute, people who enjoy the thrill of activities, 990 00:40:20,770 --> 00:40:23,160 novel, high-stimulation situations. 991 00:40:23,160 --> 00:40:26,920 Statistically they have more fun, probably, in some ways. 992 00:40:26,920 --> 00:40:29,070 They're more likely to dive, they're more likely to drive 993 00:40:29,070 --> 00:40:31,100 fast, they're more likely to have drug or alcohol use, 994 00:40:31,100 --> 00:40:32,900 they're more likely to send flame emails, listen to punk 995 00:40:32,900 --> 00:40:34,260 music, and have driving accidents. 996 00:40:34,260 --> 00:40:38,460 So it's an interesting mix of enjoyment and trouble. 997 00:40:38,460 --> 00:40:41,540 And there's some evidence they have lower levels of something 998 00:40:41,540 --> 00:40:44,740 in the blood that may be a measure of something that lets 999 00:40:44,740 --> 00:40:47,710 dopamine last longer in the synapse in your brain. 1000 00:40:47,710 --> 00:40:50,800 Dopamine is the reward neurotransmitter. 1001 00:40:50,800 --> 00:40:54,330 So you could imagine that if the reward hangs around 1002 00:40:54,330 --> 00:40:56,820 longer, maybe you're more drawn towards instantly 1003 00:40:56,820 --> 00:40:59,750 rewarding things. 1004 00:40:59,750 --> 00:41:04,745 Another sort of, I think, two-dimensional classification 1005 00:41:04,745 --> 00:41:06,060 of personality. 1006 00:41:06,060 --> 00:41:08,790 Again, one dimension that he focused on was this 1007 00:41:08,790 --> 00:41:11,620 introversion to extroversion or stable to unstable. 1008 00:41:11,620 --> 00:41:14,600 This is neuroticism or introversion/extroversion in 1009 00:41:14,600 --> 00:41:16,280 the big five. 1010 00:41:16,280 --> 00:41:18,220 But there's some interesting turns on this. 1011 00:41:18,220 --> 00:41:19,160 Here's the interesting turn. 1012 00:41:19,160 --> 00:41:20,380 I mentioned it, but let me tell you one more time, 1013 00:41:20,380 --> 00:41:22,250 because it's counter-intuitive. 1014 00:41:22,250 --> 00:41:24,120 It's the opposite of what you think in terms of what people 1015 00:41:24,120 --> 00:41:25,390 have found. 1016 00:41:25,390 --> 00:41:27,860 So we think of extroverts as people who go to parties, are 1017 00:41:27,860 --> 00:41:30,620 very talkative, very outgoing, run around and have a social 1018 00:41:30,620 --> 00:41:33,390 time, and introverts as more likely to be shy, quiet, 1019 00:41:33,390 --> 00:41:33,940 withdrawn, right? 1020 00:41:33,940 --> 00:41:36,920 That's the definitions of the words. 1021 00:41:36,920 --> 00:41:39,495 But what people have found in a variety of studies is that 1022 00:41:39,495 --> 00:41:40,310 extroverts-- the outgoing people-- 1023 00:41:40,310 --> 00:41:42,710 are less easily aroused. 1024 00:41:42,710 --> 00:41:44,020 So it's as if they seek stimulation. 1025 00:41:44,020 --> 00:41:48,110 It's as if their internal arousal is low, and they want 1026 00:41:48,110 --> 00:41:50,280 things that are stimulating in their environment to push up 1027 00:41:50,280 --> 00:41:52,400 their internal arousal, right? 1028 00:41:52,400 --> 00:41:54,170 Introverts are the opposite around. 1029 00:41:54,170 --> 00:41:57,460 Introverts are aroused already, and it's as if they 1030 00:41:57,460 --> 00:42:00,780 seek environments that are quiet, so their arousal is not 1031 00:42:00,780 --> 00:42:02,820 pushed above some level of discomfort. 1032 00:42:02,820 --> 00:42:05,120 So intuitively you might think extroverts are more aroused 1033 00:42:05,120 --> 00:42:10,530 internally, but the thought is that extroverts are actually 1034 00:42:10,530 --> 00:42:14,170 seeking arousal because they're a little lower inside. 1035 00:42:14,170 --> 00:42:16,800 Introverts are already feeling pretty aroused, so they don't 1036 00:42:16,800 --> 00:42:19,630 need more bungee jumping. 1037 00:42:19,630 --> 00:42:22,690 They're already feeling like they're bungee jumping, OK? 1038 00:42:22,690 --> 00:42:24,760 So then they're all seeking this sort of 1039 00:42:24,760 --> 00:42:26,260 optimal level of arousal. 1040 00:42:26,260 --> 00:42:29,070 So, for example, extroverts do better in noisy settings, they 1041 00:42:29,070 --> 00:42:32,900 can take the extra stuff, they don't mind it. 1042 00:42:32,900 --> 00:42:35,820 Introverts are more sensitive to pain, and they salivate 1043 00:42:35,820 --> 00:42:36,700 more to lemon juice. 1044 00:42:36,700 --> 00:42:41,570 They're already kind of revved up, is the story, internally. 1045 00:42:41,570 --> 00:42:43,730 So here's one-- 1046 00:42:43,730 --> 00:42:46,560 we couldn't do this early in the course, and this almost 1047 00:42:46,560 --> 00:42:48,420 has practical concept-- 1048 00:42:48,420 --> 00:42:51,040 you could think about this for your own test taking. 1049 00:42:51,040 --> 00:42:53,025 A three-way interaction. 1050 00:42:53,025 --> 00:42:55,690 This is three factors that all interact with one another in 1051 00:42:55,690 --> 00:42:58,790 performance, and it involves situation and personality. 1052 00:42:58,790 --> 00:42:59,970 So here we go. 1053 00:42:59,970 --> 00:43:01,840 So the three factors are whether you're introverted or 1054 00:43:01,840 --> 00:43:05,540 extroverted, whether you're taking a test-- a GRE kind of 1055 00:43:05,540 --> 00:43:08,610 a test-- in the morning or the afternoon, and whether you 1056 00:43:08,610 --> 00:43:11,390 drank a cup of coffee before the test or not. 1057 00:43:11,390 --> 00:43:14,160 Three different things floating around. 1058 00:43:14,160 --> 00:43:16,010 And here's what people have found several times in 1059 00:43:16,010 --> 00:43:18,920 experiments when you're taking a test. 1060 00:43:18,920 --> 00:43:20,840 Here's the upshot of the studies. 1061 00:43:20,840 --> 00:43:25,180 If you're introverted and the test is in the late afternoon 1062 00:43:25,180 --> 00:43:27,210 or evening, drink coffee. 1063 00:43:27,210 --> 00:43:30,230 If you're outgoing, drink coffee in the morning. 1064 00:43:30,230 --> 00:43:32,820 And I'll tell you the logic of this. 1065 00:43:32,820 --> 00:43:35,500 All right? 1066 00:43:35,500 --> 00:43:37,140 So here's the idea. 1067 00:43:37,140 --> 00:43:39,190 Many studies have shown-- and you may know this, if you 1068 00:43:39,190 --> 00:43:41,250 think about people you know or yourself. 1069 00:43:41,250 --> 00:43:43,630 On average, introverts are most aroused in the morning. 1070 00:43:43,630 --> 00:43:45,240 They tend to be get up early in the morning and get their 1071 00:43:45,240 --> 00:43:46,430 day going people. 1072 00:43:46,430 --> 00:43:48,310 Maybe because they didn't party deep into 1073 00:43:48,310 --> 00:43:50,400 the previous night. 1074 00:43:50,400 --> 00:43:52,345 There's cause and effect that's really hard to pull out 1075 00:43:52,345 --> 00:43:54,520 in all of this. 1076 00:43:54,520 --> 00:43:56,340 But introverts are more aroused in the morning and 1077 00:43:56,340 --> 00:43:57,620 less in the evening. 1078 00:43:57,620 --> 00:43:59,206 On average, they're the kind of people who are get up early 1079 00:43:59,206 --> 00:44:00,500 in the morning, go do their stuff. 1080 00:44:00,500 --> 00:44:03,450 In the evening they want to mellow down and maybe not go 1081 00:44:03,450 --> 00:44:04,450 to sleep so late. 1082 00:44:04,450 --> 00:44:06,590 Extroverts are more aroused in the evening, 1083 00:44:06,590 --> 00:44:07,810 and less in the morning. 1084 00:44:07,810 --> 00:44:09,300 And this is on average, and this has been 1085 00:44:09,300 --> 00:44:10,650 found a number of times. 1086 00:44:10,650 --> 00:44:13,050 So again, you can imagine if you're taking a test, if 1087 00:44:13,050 --> 00:44:16,040 you're under-aroused, you could use the 1088 00:44:16,040 --> 00:44:17,070 coffee to perk you up. 1089 00:44:17,070 --> 00:44:18,830 If you're over-aroused, the coffee is going to make you 1090 00:44:18,830 --> 00:44:20,470 jittery and push you over. 1091 00:44:20,470 --> 00:44:22,260 So depending on the time of day, you're going to be in one 1092 00:44:22,260 --> 00:44:23,430 state or the other depending on the kind of 1093 00:44:23,430 --> 00:44:24,190 personality you have. 1094 00:44:24,190 --> 00:44:24,710 Does that make sense? 1095 00:44:24,710 --> 00:44:28,070 These three things come together like that in the 1096 00:44:28,070 --> 00:44:30,660 famous Yerkes-Dodson Law of performance, which is this. 1097 00:44:30,660 --> 00:44:33,030 And this is observed in many years. 1098 00:44:33,030 --> 00:44:34,830 Here's arousal, how aroused you are. 1099 00:44:34,830 --> 00:44:39,030 Super aroused, super nervous, shaky, so sleepy you're about 1100 00:44:39,030 --> 00:44:41,110 to crash out. 1101 00:44:41,110 --> 00:44:42,540 Somewhere in the middle usually goes with best 1102 00:44:42,540 --> 00:44:46,130 performance, because this is too much, 1103 00:44:46,130 --> 00:44:46,950 and this is too little. 1104 00:44:46,950 --> 00:44:47,630 You know that. 1105 00:44:47,630 --> 00:44:49,900 If you're too nervous, you don't tend to perform well. 1106 00:44:49,900 --> 00:44:52,760 If you're too kind of out of it, you don't perform well. 1107 00:44:52,760 --> 00:44:55,830 Somewhere in the middle is just right. 1108 00:44:55,830 --> 00:44:58,690 So here's extroverts, for example. 1109 00:44:58,690 --> 00:45:02,460 In the morning, they're pretty low on this, they could use 1110 00:45:02,460 --> 00:45:04,860 some coffee to move to optimal. 1111 00:45:04,860 --> 00:45:06,976 Here's introverts in the morning, they're already ready 1112 00:45:06,976 --> 00:45:08,720 to go, I'm ready to go, I'm ready to go. 1113 00:45:08,720 --> 00:45:11,820 The last thing they need is more coffee. 1114 00:45:11,820 --> 00:45:14,520 I hope it's not a bubble test because my hands are shaking. 1115 00:45:14,520 --> 00:45:15,050 OK? 1116 00:45:15,050 --> 00:45:17,490 So three things. 1117 00:45:17,490 --> 00:45:20,450 The kind of personality you are, the time of day, and 1118 00:45:20,450 --> 00:45:22,920 whether your drinking coffee helps you to move to this 1119 00:45:22,920 --> 00:45:23,880 middle position or not. 1120 00:45:23,880 --> 00:45:25,420 Does that makes sense? 1121 00:45:25,420 --> 00:45:27,760 So that's three different factors sort of adding up to 1122 00:45:27,760 --> 00:45:30,120 optimize performance or not. 1123 00:45:30,120 --> 00:45:33,390 OK, lastly I'd like to talk a little bit about some things 1124 00:45:33,390 --> 00:45:37,400 we know about brain correlates of personality. 1125 00:45:37,400 --> 00:45:42,480 And in some areas, these brain things are more informative at 1126 00:45:42,480 --> 00:45:43,490 a broad level. 1127 00:45:43,490 --> 00:45:45,420 Because sometimes people will say, well, personality is all 1128 00:45:45,420 --> 00:45:46,900 this check box stuff. 1129 00:45:46,900 --> 00:45:48,830 Is it even relevant to anything biological? 1130 00:45:48,830 --> 00:45:50,900 Now, if it's relevant to behavior, 1131 00:45:50,900 --> 00:45:52,370 it's relevant to biology. 1132 00:45:52,370 --> 00:45:56,140 Behavior is biology, or biology is behavior. 1133 00:45:56,140 --> 00:45:57,650 We're not going to get one relative to the other. 1134 00:45:57,650 --> 00:46:00,490 But still, until recently, people couldn't measure this. 1135 00:46:00,490 --> 00:46:01,780 So these are pictures of-- 1136 00:46:01,780 --> 00:46:04,530 not of brain functions, of a task turning on-- we'll see 1137 00:46:04,530 --> 00:46:05,920 pictures of those in a moment. 1138 00:46:05,920 --> 00:46:09,510 This is measurement of brain structure. 1139 00:46:09,510 --> 00:46:11,880 Measurement of brain structure. 1140 00:46:11,880 --> 00:46:15,470 And specifically, thickness of cortex. 1141 00:46:15,470 --> 00:46:17,920 So what you're seeing is a statistic here, which is, the 1142 00:46:17,920 --> 00:46:20,710 more extroverted you are, the thicker your cortex is here. 1143 00:46:20,710 --> 00:46:23,740 The more conscientious, the thicker your cortex here. 1144 00:46:23,740 --> 00:46:28,700 The more neurotic, the thicker your cortex here, and so on. 1145 00:46:28,700 --> 00:46:31,720 So we don't understand these deeply, but we do see 1146 00:46:31,720 --> 00:46:34,130 physically measurable correlates of these 1147 00:46:34,130 --> 00:46:36,250 personality dimensions. 1148 00:46:36,250 --> 00:46:38,500 So that's physical brain structure. 1149 00:46:38,500 --> 00:46:40,090 Let's talk about some function things. 1150 00:46:40,090 --> 00:46:44,370 This is a slide you saw before that in the amygdala, the more 1151 00:46:44,370 --> 00:46:46,960 emotionally intense something is, the more the response. 1152 00:46:46,960 --> 00:46:50,890 The more neutral it is, the less the response. 1153 00:46:50,890 --> 00:46:53,170 Here's a positive happy picture, right? 1154 00:46:53,170 --> 00:46:54,140 I'm going to show you a neutral picture. 1155 00:46:54,140 --> 00:46:56,140 I'm going to show you now the bad picture. 1156 00:46:56,140 --> 00:46:57,470 Don't look if you don't want to see it again. 1157 00:46:57,470 --> 00:46:58,260 It's the one you saw before. 1158 00:46:58,260 --> 00:46:59,250 Close your eyes for a moment. 1159 00:46:59,250 --> 00:46:59,850 Bad picture. 1160 00:46:59,850 --> 00:47:00,010 OK. 1161 00:47:00,010 --> 00:47:00,580 Here we go. 1162 00:47:00,580 --> 00:47:01,940 Now you can all look. 1163 00:47:01,940 --> 00:47:04,990 So people are introverted or extroverted. 1164 00:47:04,990 --> 00:47:07,560 Extroverts are sociable, talkative. 1165 00:47:07,560 --> 00:47:11,020 Introverts are, on average, more reserved or quiet. 1166 00:47:11,020 --> 00:47:14,150 Extroverts report more positive experiences, more 1167 00:47:14,150 --> 00:47:16,120 susceptible to positive mood induction. 1168 00:47:16,120 --> 00:47:18,440 Lots of evidence for some differences among them. 1169 00:47:18,440 --> 00:47:20,520 So imagine a study where you show people positive and 1170 00:47:20,520 --> 00:47:21,320 negative slides. 1171 00:47:21,320 --> 00:47:24,510 Again, people will say, well, if I'm on a diet, this is 1172 00:47:24,510 --> 00:47:28,230 really negative, or something. 1173 00:47:28,230 --> 00:47:29,090 You have people rate them. 1174 00:47:29,090 --> 00:47:30,760 But on average these are negative, and on average these 1175 00:47:30,760 --> 00:47:32,790 are positive. 1176 00:47:32,790 --> 00:47:36,120 You measure their personality, and here's what you find in 1177 00:47:36,120 --> 00:47:37,370 the amygdala. 1178 00:47:39,170 --> 00:47:43,590 The more extroverted they are, the more their amygdala 1179 00:47:43,590 --> 00:47:46,060 responds to positive things. 1180 00:47:46,060 --> 00:47:48,480 The more introverted they are, the more it responds to 1181 00:47:48,480 --> 00:47:50,830 negative things. 1182 00:47:50,830 --> 00:47:53,390 So here's exactly what we mean by personality sort of 1183 00:47:53,390 --> 00:47:54,220 instantiated in one example. 1184 00:47:54,220 --> 00:47:55,990 And it's not the only example. 1185 00:47:55,990 --> 00:47:57,030 What do we mean by personality? 1186 00:47:57,030 --> 00:47:59,370 We mean there's a constant situation-- 1187 00:47:59,370 --> 00:48:01,760 let's pretend a party you go to. 1188 00:48:01,760 --> 00:48:03,090 A party deep in my memory. 1189 00:48:03,090 --> 00:48:05,310 I remember parties I went to, the music is playing, and 1190 00:48:05,310 --> 00:48:07,930 there's sticky beer on the floor, and there's people you 1191 00:48:07,930 --> 00:48:09,590 know and a lot of people you don't know, right? 1192 00:48:09,590 --> 00:48:12,810 So who walks in the door and thinks this is awesome? 1193 00:48:12,810 --> 00:48:14,230 The extrovert, right? 1194 00:48:14,230 --> 00:48:17,240 Who walks in the door and thinks why did my friend drag 1195 00:48:17,240 --> 00:48:17,720 me to this? 1196 00:48:17,720 --> 00:48:20,500 I could be doing something good like chess at home. 1197 00:48:23,090 --> 00:48:26,270 So now, identical situation, different-- but that's true of 1198 00:48:26,270 --> 00:48:27,970 so many things and preferences in life. 1199 00:48:27,970 --> 00:48:29,950 That's almost what we mean by personality, right? 1200 00:48:29,950 --> 00:48:31,750 Who likes what? 1201 00:48:31,750 --> 00:48:34,020 Situations, people, activities. 1202 00:48:34,020 --> 00:48:38,230 So for extroversion, here's the amygdala going, positive 1203 00:48:38,230 --> 00:48:39,410 things, whoopee! 1204 00:48:39,410 --> 00:48:42,620 They notice, so to speak, in their amygdala the positivity 1205 00:48:42,620 --> 00:48:43,210 of the environment. 1206 00:48:43,210 --> 00:48:45,250 They're drawn to things because they see positive. 1207 00:48:45,250 --> 00:48:47,850 Here is the introverts going, danger, danger. 1208 00:48:47,850 --> 00:48:48,570 OK? 1209 00:48:48,570 --> 00:48:51,030 Everybody sees the same set of slides, but people are drawn 1210 00:48:51,030 --> 00:48:53,580 to the positive or the negative aspects of this. 1211 00:48:53,580 --> 00:48:54,850 And you could say, is one better, the other worse? 1212 00:48:54,850 --> 00:48:55,710 Well, no. 1213 00:48:55,710 --> 00:48:58,110 Avoiding dangerous things is a good idea. 1214 00:48:58,110 --> 00:49:00,130 Enjoying positive things is a good idea. 1215 00:49:00,130 --> 00:49:01,830 One is not better than the other. 1216 00:49:01,830 --> 00:49:02,850 They're just different. 1217 00:49:02,850 --> 00:49:05,570 You're tuned to different rewards in life. 1218 00:49:05,570 --> 00:49:07,490 And this is one example of that. 1219 00:49:07,490 --> 00:49:09,440 How about a smiling face? 1220 00:49:09,440 --> 00:49:12,610 Who thinks a smiling face is an invitation to go over and 1221 00:49:12,610 --> 00:49:13,290 meet somebody new? 1222 00:49:13,290 --> 00:49:15,760 The introvert or the extrovert? 1223 00:49:15,760 --> 00:49:16,646 Help me on this. 1224 00:49:16,646 --> 00:49:18,820 Who thinks the smiling face is pressure? 1225 00:49:18,820 --> 00:49:19,770 Do I go over? 1226 00:49:19,770 --> 00:49:21,020 Are they smiling at me? 1227 00:49:23,696 --> 00:49:25,450 Or I'm going to go over and then they're 1228 00:49:25,450 --> 00:49:26,700 not gonna like me. 1229 00:49:26,700 --> 00:49:28,260 They like me now, right? 1230 00:49:28,260 --> 00:49:31,220 I should tell you, I was quite-- 1231 00:49:31,220 --> 00:49:33,920 only in my teaching mode do I appear extroverted, OK? 1232 00:49:33,920 --> 00:49:35,310 But I definitely was an introvert in 1233 00:49:35,310 --> 00:49:36,550 high school and college. 1234 00:49:36,550 --> 00:49:38,080 So if I make fun of introverts, I'm 1235 00:49:38,080 --> 00:49:40,820 making fun of myself. 1236 00:49:40,820 --> 00:49:43,970 So here's a response to fearful faces. 1237 00:49:43,970 --> 00:49:45,910 And we talked about that before, response in the 1238 00:49:45,910 --> 00:49:48,040 amygdala regardless of personality. 1239 00:49:48,040 --> 00:49:50,700 But now when we talk about the response in the amygdala for 1240 00:49:50,700 --> 00:49:55,070 happy faces, big response if you're extroverted, little 1241 00:49:55,070 --> 00:49:56,790 response if you're introverted. 1242 00:49:56,790 --> 00:49:59,630 Because a happy face is like compelling, cool, wonderful 1243 00:49:59,630 --> 00:50:04,780 for the extrovert, and not as enticing for the introvert. 1244 00:50:04,780 --> 00:50:07,670 So again, the way we might imagine, how do individual 1245 00:50:07,670 --> 00:50:08,980 differences in personality play out? 1246 00:50:08,980 --> 00:50:12,130 They play out that some things are beguiling, wonderful, and 1247 00:50:12,130 --> 00:50:13,070 other things not so much. 1248 00:50:13,070 --> 00:50:15,652 And depending on your personality, that can vary. 1249 00:50:19,350 --> 00:50:22,620 So these are the children who were studied from the ages of 1250 00:50:22,620 --> 00:50:29,130 two and four months who were shy in temperament, 1251 00:50:29,130 --> 00:50:30,700 inhibited, in orange. 1252 00:50:30,700 --> 00:50:33,035 And they compared them to the most uninhibited. 1253 00:50:33,035 --> 00:50:34,680 They take the extremes. 1254 00:50:34,680 --> 00:50:36,950 But it's a very rare thing when you have a behavioral 1255 00:50:36,950 --> 00:50:40,770 assessment of a child in their infancy, and then you brain 1256 00:50:40,770 --> 00:50:44,950 image them about 20 years later when they're grown up. 1257 00:50:44,950 --> 00:50:48,440 So now you're making this 20 years of your life story, and 1258 00:50:48,440 --> 00:50:51,380 again in the amygdala, what they find is this. 1259 00:50:51,380 --> 00:50:56,080 If you look at the people who are uninhibited, here's a 1260 00:50:56,080 --> 00:50:58,570 novel face they see for the first time in the scanner, or 1261 00:50:58,570 --> 00:51:00,440 a face they've seen many times, and there's not much 1262 00:51:00,440 --> 00:51:01,770 difference. 1263 00:51:01,770 --> 00:51:03,380 For the people who are inhibited, you see a much 1264 00:51:03,380 --> 00:51:05,990 bigger amygdala response to the novel face. 1265 00:51:05,990 --> 00:51:08,130 Well, this is exactly what you might intuitively think 1266 00:51:08,130 --> 00:51:09,930 shyness would be about. 1267 00:51:09,930 --> 00:51:12,490 If you're a shy person and you know somebody well, I think a 1268 00:51:12,490 --> 00:51:14,440 lot of shyness disappears. 1269 00:51:14,440 --> 00:51:17,460 But where shyness shows the most is a face that you don't 1270 00:51:17,460 --> 00:51:20,560 know, a new person you haven't met, and maybe you're not so 1271 00:51:20,560 --> 00:51:22,290 comfortable with them yet. 1272 00:51:22,290 --> 00:51:25,300 So this is exactly the pattern you might expect, that it 1273 00:51:25,300 --> 00:51:27,470 doesn't matter too much for an extrovert, a new face, a 1274 00:51:27,470 --> 00:51:28,910 familiar face-- 1275 00:51:28,910 --> 00:51:30,635 made familiar in the experiment, not somebody you 1276 00:51:30,635 --> 00:51:31,470 really know-- 1277 00:51:31,470 --> 00:51:33,230 it doesn't make much of a difference. 1278 00:51:33,230 --> 00:51:35,825 For the person who is inhibited, much more response 1279 00:51:35,825 --> 00:51:38,585 to the face they see for the first time only, as opposed to 1280 00:51:38,585 --> 00:51:42,275 a face they've grown familiar with. 1281 00:51:42,275 --> 00:51:45,130 A couple more examples along this line. 1282 00:51:45,130 --> 00:51:46,010 Here's another scale. 1283 00:51:46,010 --> 00:51:47,550 There's an infinite number of them. 1284 00:51:47,550 --> 00:51:50,340 The Spielberger State and Trait Anxiety, so, state and 1285 00:51:50,340 --> 00:51:50,980 trait, right? 1286 00:51:50,980 --> 00:51:53,720 So they ask you-- this is just a reminder of that-- 1287 00:51:53,720 --> 00:51:54,750 how do you feel right now? 1288 00:51:54,750 --> 00:51:55,520 That would be your state. 1289 00:51:55,520 --> 00:51:56,210 Right now. 1290 00:51:56,210 --> 00:51:57,280 Do I feel at ease? 1291 00:51:57,280 --> 00:51:58,400 Do I feel upset? 1292 00:51:58,400 --> 00:52:00,770 And in general, how do you feel, at ease or upset? 1293 00:52:00,770 --> 00:52:04,100 So this is day in day out, this is right now. 1294 00:52:04,100 --> 00:52:07,200 We're going to focus on the trait, how you say you feel 1295 00:52:07,200 --> 00:52:08,810 day in, day out. 1296 00:52:08,810 --> 00:52:12,630 And now they're going to show you faces of people who are 1297 00:52:12,630 --> 00:52:17,020 shown in full view, or who are shown in a subliminal masked 1298 00:52:17,020 --> 00:52:19,000 version where a fear or neutral face is followed by 1299 00:52:19,000 --> 00:52:19,730 another face. 1300 00:52:19,730 --> 00:52:21,010 This is the critical face. 1301 00:52:21,010 --> 00:52:24,060 So you see a face that you see pretty well, or you see a face 1302 00:52:24,060 --> 00:52:26,310 that's presented under circumstances where you can't 1303 00:52:26,310 --> 00:52:28,820 tell what the face was. 1304 00:52:28,820 --> 00:52:29,880 OK? 1305 00:52:29,880 --> 00:52:32,210 At first they say, what happens if we show you the 1306 00:52:32,210 --> 00:52:34,720 regular face that you see perfectly well? 1307 00:52:34,720 --> 00:52:35,850 Nothing makes much of a difference. 1308 00:52:35,850 --> 00:52:37,550 Here's the amygdala response to fearful face. 1309 00:52:37,550 --> 00:52:39,980 You've seen this now multiple times. 1310 00:52:39,980 --> 00:52:42,620 But kind of interestingly, you get a smaller response in the 1311 00:52:42,620 --> 00:52:46,600 amygdala, and it's driven by how anxious you report 1312 00:52:46,600 --> 00:52:49,150 yourself to be on a regular basis. 1313 00:52:49,150 --> 00:52:51,630 So the interpretation is this. 1314 00:52:51,630 --> 00:52:53,930 If you see a fearful face, you go, well, it's a fearful face, 1315 00:52:53,930 --> 00:52:56,620 I know it's a fearful phase, we're all the same. 1316 00:52:56,620 --> 00:52:59,190 If you subliminally present it, you have an 1317 00:52:59,190 --> 00:53:02,080 unknown source of danger. 1318 00:53:02,080 --> 00:53:07,030 What we intuitively imagine anxiety is is feeling danger 1319 00:53:07,030 --> 00:53:10,600 or threat in your environment more than is helpful, more 1320 00:53:10,600 --> 00:53:11,950 than is comfortable. 1321 00:53:11,950 --> 00:53:12,700 OK? 1322 00:53:12,700 --> 00:53:14,330 And you don't even know exactly why. 1323 00:53:14,330 --> 00:53:16,040 It's not entirely rational when you're 1324 00:53:16,040 --> 00:53:17,790 anxious in that way. 1325 00:53:17,790 --> 00:53:20,350 And so what happens is, the more anxious you are, the more 1326 00:53:20,350 --> 00:53:24,120 these subliminal faces drive an amygdala response, and you 1327 00:53:24,120 --> 00:53:26,010 don't have control over that, because you don't know what 1328 00:53:26,010 --> 00:53:27,910 happened, because it was subliminally presented. 1329 00:53:27,910 --> 00:53:29,040 Does that make sense? 1330 00:53:29,040 --> 00:53:31,340 When it's clear, everybody knows what to do. 1331 00:53:31,340 --> 00:53:33,740 It's just a face and not that scary. 1332 00:53:33,740 --> 00:53:36,630 But when it's an unknown source of a bit of unease, the 1333 00:53:36,630 --> 00:53:39,430 more chronically anxious you are, the more the brain's 1334 00:53:39,430 --> 00:53:39,910 responding. 1335 00:53:39,910 --> 00:53:42,420 Or we might say, the bigger the brain response is the 1336 00:53:42,420 --> 00:53:47,270 basis, perhaps, of the chronic unease. 1337 00:53:47,270 --> 00:53:49,710 So we talked also before about the amygdala being important 1338 00:53:49,710 --> 00:53:53,050 for recognizing fearful expressions. 1339 00:53:53,050 --> 00:53:56,340 And then I want to share two last examples. 1340 00:53:56,340 --> 00:53:57,800 How about genetic influences? 1341 00:53:57,800 --> 00:54:00,280 So we know genes are a big part of the story, but how big 1342 00:54:00,280 --> 00:54:00,970 a part of the story? 1343 00:54:00,970 --> 00:54:02,840 So again, we talked about single nucleotide 1344 00:54:02,840 --> 00:54:06,330 polymorphisms, common genetic variance. 1345 00:54:06,330 --> 00:54:08,450 And here's one that involves a serotonin 1346 00:54:08,450 --> 00:54:10,830 transporter in the amygdala. 1347 00:54:10,830 --> 00:54:15,380 There's a short or long allele, so we'll have two of 1348 00:54:15,380 --> 00:54:16,660 these, all of us. 1349 00:54:16,660 --> 00:54:19,650 The short allele is weakly correlated 1350 00:54:19,650 --> 00:54:20,930 with anxiety traits. 1351 00:54:20,930 --> 00:54:23,890 All this genetic stuff is pretty weak at the moment, for 1352 00:54:23,890 --> 00:54:25,830 reasons that are not well understood. 1353 00:54:25,830 --> 00:54:27,630 I'm only presenting you ones that have been at least 1354 00:54:27,630 --> 00:54:28,780 replicated once. 1355 00:54:28,780 --> 00:54:31,070 But practically every genetic example I'm going to show you, 1356 00:54:31,070 --> 00:54:33,190 there's been non-confirmations as well. 1357 00:54:33,190 --> 00:54:34,740 We don't know why this is. 1358 00:54:34,740 --> 00:54:37,410 The genes are just so far away from complex human behaviors 1359 00:54:37,410 --> 00:54:38,950 is probably the answer. 1360 00:54:38,950 --> 00:54:41,710 But what has been replicated a number of times is this. 1361 00:54:41,710 --> 00:54:45,200 If they show you fearful faces, and you have the short 1362 00:54:45,200 --> 00:54:47,160 allele, the one that's slightly associated with 1363 00:54:47,160 --> 00:54:50,145 anxiety, this is the difference between people with 1364 00:54:50,145 --> 00:54:51,730 the long allele and the shorter allele, a much more 1365 00:54:51,730 --> 00:54:54,910 powerful response to fearful faces if you 1366 00:54:54,910 --> 00:54:55,790 have the shorter allele. 1367 00:54:55,790 --> 00:54:58,470 So a single gene can be correlated with a more potent 1368 00:54:58,470 --> 00:55:01,060 response to a sort of threat stimulus. 1369 00:55:01,060 --> 00:55:03,550 And again, that goes with our sense of anxiety, and what we 1370 00:55:03,550 --> 00:55:06,610 might call a less than desirable response to threat 1371 00:55:06,610 --> 00:55:08,810 in the environment. 1372 00:55:08,810 --> 00:55:12,410 So here's the last two slides. 1373 00:55:12,410 --> 00:55:17,430 But it's the dream we all have in understanding people, and 1374 00:55:17,430 --> 00:55:19,470 actually all animals on the face of this planet, but 1375 00:55:19,470 --> 00:55:22,120 people most of all if you're curious about people, which 1376 00:55:22,120 --> 00:55:25,380 is, what is the interaction between the genes we're born 1377 00:55:25,380 --> 00:55:27,730 with and the life we lead, and how does that end up 1378 00:55:27,730 --> 00:55:29,480 with us being us? 1379 00:55:29,480 --> 00:55:32,950 And it's incredibly hard to study that, because everybody 1380 00:55:32,950 --> 00:55:37,350 says in biology and neuroscience, we know it's a 1381 00:55:37,350 --> 00:55:39,780 gene by experience interaction. 1382 00:55:39,780 --> 00:55:43,020 The genes will make you strong in some circumstances and 1383 00:55:43,020 --> 00:55:44,850 vulnerable in others. 1384 00:55:44,850 --> 00:55:46,530 But it's very hard to specify that. 1385 00:55:46,530 --> 00:55:48,590 The genes have been hard to identify. 1386 00:55:48,590 --> 00:55:50,610 And we can't put people into experiments. 1387 00:55:50,610 --> 00:55:53,340 We can't say, we'll take two identical twins and we'll put 1388 00:55:53,340 --> 00:55:56,290 one into some horrible household full of stress and 1389 00:55:56,290 --> 00:55:58,720 horribleness, and then one into a delightful household, 1390 00:55:58,720 --> 00:56:00,730 and then see them at 20 and see what happened. 1391 00:56:00,730 --> 00:56:01,210 OK? 1392 00:56:01,210 --> 00:56:02,440 We're just not allowed to do that, right? 1393 00:56:02,440 --> 00:56:06,620 So we can't experiment on the environment, and the genes are 1394 00:56:06,620 --> 00:56:11,040 poorly understood, very poorly understood, in relation to 1395 00:56:11,040 --> 00:56:12,850 basic human behaviors. 1396 00:56:12,850 --> 00:56:15,630 But there's a study from Caspi that is a glimpse of where we 1397 00:56:15,630 --> 00:56:16,730 think the field might be going. 1398 00:56:16,730 --> 00:56:19,200 But I'm going to warn you that this has not always been 1399 00:56:19,200 --> 00:56:20,520 replicated. 1400 00:56:20,520 --> 00:56:22,150 It's been replicated sometimes, 1401 00:56:22,150 --> 00:56:22,940 but not other times. 1402 00:56:22,940 --> 00:56:26,700 So it's an asterisk, but it's still a finding that's really 1403 00:56:26,700 --> 00:56:29,790 quite striking, if it turns out to be roughly correct. 1404 00:56:29,790 --> 00:56:32,800 So again, this is polymorphism of the same gene that's 1405 00:56:32,800 --> 00:56:34,880 associated with anxiety. 1406 00:56:34,880 --> 00:56:37,870 And what they did in a very large sample in New Zealand 1407 00:56:37,870 --> 00:56:46,040 was catalog stressful life events ages 21 to 26, job, 1408 00:56:46,040 --> 00:56:48,820 whether you have a job or not, your salary, decent housing, 1409 00:56:48,820 --> 00:56:50,950 terrible housing, good health, bad health, happy 1410 00:56:50,950 --> 00:56:52,830 relationships, no relationships, terrible 1411 00:56:52,830 --> 00:56:53,480 relationships. 1412 00:56:53,480 --> 00:56:55,940 People are filling out forms telling you about the stresses 1413 00:56:55,940 --> 00:56:57,530 in their life. 1414 00:56:57,530 --> 00:57:00,830 And then they also have information about childhood 1415 00:57:00,830 --> 00:57:01,380 maltreatment. 1416 00:57:01,380 --> 00:57:04,700 Some of these children, very sadly, when they were younger 1417 00:57:04,700 --> 00:57:07,080 were treated very poorly, they were abused in some way or 1418 00:57:07,080 --> 00:57:10,610 another, were in very terrible circumstances, and some not. 1419 00:57:10,610 --> 00:57:12,920 So they're going to look at stressful events in childhood 1420 00:57:12,920 --> 00:57:18,350 and adulthood, and sort them out by the allele that the 1421 00:57:18,350 --> 00:57:21,720 individuals have, the gene version, and what they find 1422 00:57:21,720 --> 00:57:23,360 is-- and I'll show you the graph in a moment-- 1423 00:57:23,360 --> 00:57:25,680 more depression and suicidality in response to 1424 00:57:25,680 --> 00:57:29,310 stressful events if you have a short version of the allele. 1425 00:57:29,310 --> 00:57:31,650 The short version, we just said, is the one that seems to 1426 00:57:31,650 --> 00:57:35,025 drive a bigger anxiety response to fearful faces in 1427 00:57:35,025 --> 00:57:36,220 the amygdala, OK? 1428 00:57:36,220 --> 00:57:40,570 So it seems, first pass, to be a gene that's associated with 1429 00:57:40,570 --> 00:57:45,120 responding in a more anxious way to environmental stress, 1430 00:57:45,120 --> 00:57:47,810 threat, and bad things. 1431 00:57:47,810 --> 00:57:49,010 So here's a couple of graphs. 1432 00:57:49,010 --> 00:57:50,430 I'll just do a couple with you. 1433 00:57:50,430 --> 00:57:55,170 Here's the probability of major depression if you've had 1434 00:57:55,170 --> 00:57:59,130 no maltreatment as a child, if you've probably had some, or 1435 00:57:59,130 --> 00:58:02,650 you've had documented horrible maltreatment as a child. 1436 00:58:02,650 --> 00:58:04,920 And what you can see if you have the long version-- this 1437 00:58:04,920 --> 00:58:06,070 is this line here-- 1438 00:58:06,070 --> 00:58:09,610 the long version of this allele, no difference. 1439 00:58:09,610 --> 00:58:14,910 It's as if if you happen to be born in the biological lottery 1440 00:58:14,910 --> 00:58:18,920 that we all participate in at birth with these version of 1441 00:58:18,920 --> 00:58:21,140 these genes-- and maybe many other genes that are part of 1442 00:58:21,140 --> 00:58:23,890 this story, but they just measured this one. 1443 00:58:23,890 --> 00:58:27,610 That it doesn't matter whether you live in a nice supportive 1444 00:58:27,610 --> 00:58:30,970 environment or a brutalizing, horrible one, your probability 1445 00:58:30,970 --> 00:58:32,800 of depression is about the same. 1446 00:58:32,800 --> 00:58:36,560 It's a protective gene for stresses of life that are 1447 00:58:36,560 --> 00:58:37,900 visited upon you. 1448 00:58:37,900 --> 00:58:42,070 If you have the opposite, the short version, look. 1449 00:58:42,070 --> 00:58:44,840 The worse the environment, you double your chances of 1450 00:58:44,840 --> 00:58:46,230 depression. 1451 00:58:46,230 --> 00:58:50,660 It's as if you're born with a gene that, if you're given a 1452 00:58:50,660 --> 00:58:51,910 terrible environment-- 1453 00:58:51,910 --> 00:58:54,200 this is exactly the interaction, right-- 1454 00:58:54,200 --> 00:58:57,090 then you're very susceptible to that. 1455 00:58:57,090 --> 00:59:01,540 And you see the same rough pattern in all of them, that 1456 00:59:01,540 --> 00:59:05,310 individuals who have this version of the gene seem to be 1457 00:59:05,310 --> 00:59:09,520 relatively impervious to environmental stressors. 1458 00:59:09,520 --> 00:59:11,800 The ones born with this version of the gene are 1459 00:59:11,800 --> 00:59:14,310 terribly-- so if this person's born with this version of the 1460 00:59:14,310 --> 00:59:15,880 gene, but happens to be in a nice supportive 1461 00:59:15,880 --> 00:59:17,550 household, no problem. 1462 00:59:17,550 --> 00:59:19,010 Right? 1463 00:59:19,010 --> 00:59:21,870 But if they happen to be born into a household where they 1464 00:59:21,870 --> 00:59:26,200 experience, sadly, severe maltreatment, big problem. 1465 00:59:26,200 --> 00:59:28,300 And so this is exactly what we imagine if we understood in 1466 00:59:28,300 --> 00:59:32,100 any depth what people are about, the genetic 1467 00:59:32,100 --> 00:59:34,600 potentiations you're born with, what's easy for you or 1468 00:59:34,600 --> 00:59:36,640 hard for you by genes. 1469 00:59:36,640 --> 00:59:39,380 And the world your handed as an infant, not under your 1470 00:59:39,380 --> 00:59:41,600 control, but the environment you're given, supportive or 1471 00:59:41,600 --> 00:59:45,480 threatening, how those two things play out in a sort of 1472 00:59:45,480 --> 00:59:50,640 duet, making you safe or putting you at risk. 1473 00:59:50,640 --> 00:59:52,320 That's exactly what would-- then we would deeply 1474 00:59:52,320 --> 00:59:57,190 understand the biology and the psychology of human life. 1475 00:59:57,190 --> 00:59:58,840 So this is the kind of study that gets a lot of attention, 1476 00:59:58,840 --> 01:00:01,705 because if we had it exactly right, which we don't yet, we 1477 01:00:01,705 --> 01:00:03,890 would understand something really deep about people and 1478 01:00:03,890 --> 01:00:05,140 vulnerability in environments.