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 --> 00:00:19,290 hundreds of MIT courses, visit MIT OpenCourseWare at 7 00:00:19,290 --> 00:00:20,540 ocw.mit.edu. 8 00:00:27,572 --> 00:00:29,470 PROFESSOR: OK, good afternoon. 9 00:00:29,470 --> 00:00:33,030 So in the last couple of weeks, we've gone through some 10 00:00:33,030 --> 00:00:37,060 of the major human capacities that you have and I have and 11 00:00:37,060 --> 00:00:38,840 most people have most of them, right? 12 00:00:38,840 --> 00:00:43,530 Which are the ability to see the world around us, to attend 13 00:00:43,530 --> 00:00:49,240 to what's important, to learn lessons from life, to remember 14 00:00:49,240 --> 00:00:51,580 things, why we sometimes forget things. 15 00:00:51,580 --> 00:00:53,880 And today, we're going to talk about another huge dimension 16 00:00:53,880 --> 00:00:57,200 of human experience, of the human mind, of the human 17 00:00:57,200 --> 00:00:58,940 brain, language. 18 00:00:58,940 --> 00:01:00,900 The ability to talk to one another. 19 00:01:00,900 --> 00:01:02,900 I can talk, you can listen, and vice versa. 20 00:01:02,900 --> 00:01:06,060 To read, to communicate, in the ways that are so 21 00:01:06,060 --> 00:01:07,580 remarkable. 22 00:01:07,580 --> 00:01:10,270 Our life is flooded with language, right? 23 00:01:10,270 --> 00:01:13,910 That we hear, that we read, and so on. 24 00:01:13,910 --> 00:01:18,040 So when psychologists try to divide up language and the 25 00:01:18,040 --> 00:01:20,610 study of both components, they talk about comprehension, 26 00:01:20,610 --> 00:01:22,800 understanding what somebody says to you when you're an 27 00:01:22,800 --> 00:01:27,900 infant, or now, as an adult, or reading text, or producing 28 00:01:27,900 --> 00:01:30,720 speech, which you can do with your mouth by speaking, or you 29 00:01:30,720 --> 00:01:31,440 learn to write. 30 00:01:31,440 --> 00:01:34,230 So you can both comprehend and produce language, both 31 00:01:34,230 --> 00:01:36,340 visually and orally. 32 00:01:36,340 --> 00:01:41,720 And the thing that has greatly enamored linguists to figure 33 00:01:41,720 --> 00:01:45,400 out is how language that we speak is endlessly generative. 34 00:01:45,400 --> 00:01:47,980 I'm not sure you can actually calculate out how many 35 00:01:47,980 --> 00:01:50,600 sentences we could possibly produce, but just for fun, 36 00:01:50,600 --> 00:01:51,590 people have done stuff. 37 00:01:51,590 --> 00:01:53,870 And they said it would take 100 trillion years to memorize 38 00:01:53,870 --> 00:01:55,460 all the sentences we can produce. 39 00:01:55,460 --> 00:01:56,890 I'm not sure that's exactly the right 40 00:01:56,890 --> 00:01:58,540 number, but it's a lot. 41 00:01:58,540 --> 00:02:00,670 Because we can say a lot of different sentences and 42 00:02:00,670 --> 00:02:02,030 understand what a person is saying. 43 00:02:02,030 --> 00:02:05,970 It's an incredibly generative system for communication, one 44 00:02:05,970 --> 00:02:08,090 person to another. 45 00:02:08,090 --> 00:02:12,120 So when people in psychology think about different aspects 46 00:02:12,120 --> 00:02:14,590 of language, levels of language, they often divide it 47 00:02:14,590 --> 00:02:16,190 into something like this. 48 00:02:16,190 --> 00:02:19,140 Phonology is the sounds of language that we hear, that we 49 00:02:19,140 --> 00:02:22,700 acquire as infants, that we use to speak to one another. 50 00:02:22,700 --> 00:02:24,490 Syntax, grammar. 51 00:02:24,490 --> 00:02:27,240 And by this, this isn't school grammar, not get 52 00:02:27,240 --> 00:02:27,910 the sentence right. 53 00:02:27,910 --> 00:02:31,930 It's just the understanding of the organization of words, and 54 00:02:31,930 --> 00:02:33,610 how that changes the meaning of the sentence. 55 00:02:33,610 --> 00:02:34,930 Syntax. 56 00:02:34,930 --> 00:02:36,730 Semantics, what do the words mean? 57 00:02:36,730 --> 00:02:38,060 What do the groups of words mean? 58 00:02:38,060 --> 00:02:39,830 Pragmatics. 59 00:02:39,830 --> 00:02:42,150 And we'll talk about each of these a little bit. 60 00:02:42,150 --> 00:02:46,420 Sometimes a person is sarcastic. 61 00:02:46,420 --> 00:02:49,730 So they go, that was an awesome lecture yesterday in 62 00:02:49,730 --> 00:02:50,240 psychology. 63 00:02:50,240 --> 00:02:53,190 Somebody could say that, in a hundred trillion years. 64 00:02:53,190 --> 00:02:54,540 And you go, yeah, yeah. 65 00:02:54,540 --> 00:02:55,550 Right? 66 00:02:55,550 --> 00:02:58,490 So that's the pragmatics versus semantics. 67 00:02:58,490 --> 00:03:00,700 Then, of course, it's not just sentences. 68 00:03:00,700 --> 00:03:02,240 We have whole discussions. 69 00:03:02,240 --> 00:03:04,450 And another aspect of language we'll just touch on a little 70 00:03:04,450 --> 00:03:07,760 bit today is emotional comprehension and production. 71 00:03:07,760 --> 00:03:10,980 The tone somebody speaks in, the tone you produce, are also 72 00:03:10,980 --> 00:03:11,270 informative. 73 00:03:11,270 --> 00:03:13,740 So there's many aspects of language. 74 00:03:13,740 --> 00:03:15,890 We'll start with the most basic, or phonology. 75 00:03:15,890 --> 00:03:18,320 So phonemes are the words that people use to describe the 76 00:03:18,320 --> 00:03:20,350 building blocks of speech sounds. 77 00:03:20,350 --> 00:03:23,010 So boy versus toy are different by one phoneme. 78 00:03:23,010 --> 00:03:25,340 Phonemes are the building blocks of 79 00:03:25,340 --> 00:03:27,030 the sounds of language. 80 00:03:27,030 --> 00:03:31,580 Humans use about 100 phonemes across languages, but any 81 00:03:31,580 --> 00:03:34,540 given language only uses a subset. 82 00:03:34,540 --> 00:03:36,530 And this has really interesting consequences. 83 00:03:36,530 --> 00:03:40,020 Of course, a language could only exist in the world if you 84 00:03:40,020 --> 00:03:41,970 could understand those phonemes. 85 00:03:41,970 --> 00:03:43,435 Phonemes that are ununderstandable aren't going 86 00:03:43,435 --> 00:03:45,030 to be a part of anybody's language. 87 00:03:45,030 --> 00:03:47,820 But different languages, for historical reasons, have ended 88 00:03:47,820 --> 00:03:50,520 up using different subsets of phonemes. 89 00:03:50,520 --> 00:03:51,620 And we'll come back to that. 90 00:03:51,620 --> 00:03:54,480 When we're babies, for about the first six months of our 91 00:03:54,480 --> 00:03:55,830 lives, we're universal learners. 92 00:03:55,830 --> 00:03:58,440 We know all the phonemes and respond to all of them. 93 00:03:58,440 --> 00:04:01,970 As we become native language speakers and listeners, we 94 00:04:01,970 --> 00:04:05,120 become only good at the ones that are used in our language, 95 00:04:05,120 --> 00:04:07,530 and our ability to even recognize the ones that are 96 00:04:07,530 --> 00:04:09,920 not in our language disappears. 97 00:04:09,920 --> 00:04:12,370 You can get it back some, but the older that you are, you 98 00:04:12,370 --> 00:04:13,500 never get it back fully. 99 00:04:13,500 --> 00:04:17,060 So we're universal learners at birth, but we become enslaved 100 00:04:17,060 --> 00:04:20,019 to the language that we are native speakers of and listen 101 00:04:20,019 --> 00:04:21,720 to within months of birth. 102 00:04:25,430 --> 00:04:27,430 English has about 45. 103 00:04:27,430 --> 00:04:29,430 So it's more than the number of letters we have. 104 00:04:29,430 --> 00:04:30,760 Some people get confused a little bit 105 00:04:30,760 --> 00:04:31,920 that letters are phonemes. 106 00:04:31,920 --> 00:04:32,830 They're not. 107 00:04:32,830 --> 00:04:39,630 So hot and cold, the oh sound in hot and the oh sound in 108 00:04:39,630 --> 00:04:41,540 cold are different sounds, same letters. 109 00:04:41,540 --> 00:04:43,390 So there's many more phonemes. 110 00:04:43,390 --> 00:04:45,700 Even in English, when they say there's about 45, depending on 111 00:04:45,700 --> 00:04:49,520 dialects, you could have a couple more, a couple less. 112 00:04:49,520 --> 00:04:51,010 So again, we're born to use all of them. 113 00:04:51,010 --> 00:04:52,290 Then we use them or lose them. 114 00:04:52,290 --> 00:04:54,430 It's something, we don't entirely lose it, but we're 115 00:04:54,430 --> 00:04:58,150 never as good if we try to learn a distinction once we 116 00:04:58,150 --> 00:04:59,980 become older than that. 117 00:04:59,980 --> 00:05:02,660 Humans understand speech at an incredible rate. 118 00:05:02,660 --> 00:05:07,470 The typical fast talking is about 180 words a minute, 14 119 00:05:07,470 --> 00:05:09,580 phonemes a second in a continuous speech stream. 120 00:05:09,580 --> 00:05:11,560 But people can go up to 250 words. 121 00:05:11,560 --> 00:05:16,530 We're incredibly fast language processors, incredibly fast 122 00:05:16,530 --> 00:05:19,100 language processors. 123 00:05:19,100 --> 00:05:22,150 So how do we roughly conceptualize, in the most 124 00:05:22,150 --> 00:05:25,780 simple way, what we have to do to get to a word that we hear, 125 00:05:25,780 --> 00:05:26,950 to get to its meaning. 126 00:05:26,950 --> 00:05:28,910 Well, acoustic information comes through the ear. 127 00:05:28,910 --> 00:05:33,850 Those are wave forms, physical things, arriving at our ears. 128 00:05:33,850 --> 00:05:37,650 We in some way figure out how those correspond to phonemes, 129 00:05:37,650 --> 00:05:40,260 and then map that in some way to words that have 130 00:05:40,260 --> 00:05:41,510 meanings in the world. 131 00:05:44,450 --> 00:05:49,300 And the reason why machines understanding what you say is 132 00:05:49,300 --> 00:05:52,200 shockingly hard to do a good job on is for 133 00:05:52,200 --> 00:05:54,390 the following reason. 134 00:05:54,390 --> 00:05:57,400 There's a huge difference between a word by the time 135 00:05:57,400 --> 00:06:00,360 your mind understands what it is and the nature of the 136 00:06:00,360 --> 00:06:02,210 signal that arrived at your year. 137 00:06:02,210 --> 00:06:03,770 So we talked a lot about that in terms of 138 00:06:03,770 --> 00:06:05,440 the retina in vision. 139 00:06:05,440 --> 00:06:05,940 Right? 140 00:06:05,940 --> 00:06:08,170 You have this very impoverished stuff that 141 00:06:08,170 --> 00:06:10,670 arrives in your retina, and then the whole rest of your 142 00:06:10,670 --> 00:06:13,990 brain, millions and millions of neurons and synapses, 143 00:06:13,990 --> 00:06:17,780 reconstruct what's out there from a very impoverished 144 00:06:17,780 --> 00:06:19,110 retinal input. 145 00:06:19,110 --> 00:06:20,860 And the same thing happens in audition. 146 00:06:20,860 --> 00:06:24,700 What gets to your ear is incredibly impoverished, and 147 00:06:24,700 --> 00:06:27,790 the rest of your brain has to brilliantly reconstruct what 148 00:06:27,790 --> 00:06:30,370 it heard and assign its meaning. 149 00:06:30,370 --> 00:06:33,430 And so part of the challenge of your mind and brain to do 150 00:06:33,430 --> 00:06:34,430 that is this. 151 00:06:34,430 --> 00:06:36,660 This is a representation of something like the physical 152 00:06:36,660 --> 00:06:39,190 signal that arrives at your ear. 153 00:06:39,190 --> 00:06:41,190 And you could say, well, here's one word. 154 00:06:41,190 --> 00:06:41,850 Here's another word. 155 00:06:41,850 --> 00:06:43,260 What's the problem? 156 00:06:43,260 --> 00:06:46,410 But this is all the signal that arrives at your ear for 157 00:06:46,410 --> 00:06:48,840 the word captain. 158 00:06:48,840 --> 00:06:54,450 So here's the C, all this stuff for the A, a period of 159 00:06:54,450 --> 00:06:58,370 long silence that sets up the P. Turns out-- 160 00:06:58,370 --> 00:07:00,220 I'll convince you of this in a moment-- 161 00:07:00,220 --> 00:07:03,970 that our speech is full within words of silent breaks that 162 00:07:03,970 --> 00:07:07,150 are incredibly informative and alter our perception of what's 163 00:07:07,150 --> 00:07:09,630 physically going on. 164 00:07:09,630 --> 00:07:12,630 Then the little T. This long stuff for the AI. 165 00:07:12,630 --> 00:07:14,200 This long stuff for the N. 166 00:07:14,200 --> 00:07:18,720 So the physical signal to your ear barely resembles what 167 00:07:18,720 --> 00:07:21,190 seems like a single unit, captain. 168 00:07:21,190 --> 00:07:22,740 And where's that pause? 169 00:07:22,740 --> 00:07:26,450 A person doesn't say, "cap," or doesn't say "ca," one, two, 170 00:07:26,450 --> 00:07:29,380 three, "ptain." Right? 171 00:07:29,380 --> 00:07:31,630 I mean, but the pause is happening, and it's incredibly 172 00:07:31,630 --> 00:07:32,690 informative, as I'll show you. 173 00:07:32,690 --> 00:07:34,890 So that's the incredible thing. 174 00:07:34,890 --> 00:07:37,220 Your auditory system, your language system, has to 175 00:07:37,220 --> 00:07:41,030 reconstruct sound into phonemes, into words. 176 00:07:41,030 --> 00:07:45,760 It's not obvious in the physical signal of the ear. 177 00:07:45,760 --> 00:07:48,340 It's not even that the physical signal at the ear 178 00:07:48,340 --> 00:07:52,090 gives you much information at the outset about whether 179 00:07:52,090 --> 00:07:54,680 you're hearing one word or two words or three words. 180 00:07:54,680 --> 00:07:58,520 So here's "what," and "do you mean" as one big blend. 181 00:07:58,520 --> 00:07:59,150 Where is "do"? 182 00:07:59,150 --> 00:07:59,850 Where is "you"? 183 00:07:59,850 --> 00:08:00,630 Where is "you mean"? 184 00:08:00,630 --> 00:08:02,930 And why does "what" look so separate, and these three 185 00:08:02,930 --> 00:08:08,040 words, "what do you mean," get all garbled together. 186 00:08:08,040 --> 00:08:11,670 And you have to unpack them by your brain and mind. 187 00:08:14,230 --> 00:08:15,870 Here's another example. 188 00:08:15,870 --> 00:08:18,060 John said that the dog snapped at them. 189 00:08:18,060 --> 00:08:19,370 The dog snapped. 190 00:08:19,370 --> 00:08:22,000 Here's what's coming, roughly, to your ear, 191 00:08:22,000 --> 00:08:23,310 taken from spoken speech. 192 00:08:23,310 --> 00:08:26,610 And here, again, notice that the boundaries that you can 193 00:08:26,610 --> 00:08:31,380 see here, the gaps of silence, occur not very related to the 194 00:08:31,380 --> 00:08:33,690 boundaries between the words that your mind ultimately 195 00:08:33,690 --> 00:08:34,799 understands. 196 00:08:34,799 --> 00:08:37,740 So here's the word "the," "dog". 197 00:08:37,740 --> 00:08:39,750 Here's S for "snapped". 198 00:08:39,750 --> 00:08:40,940 Here's a good pause. 199 00:08:40,940 --> 00:08:43,809 But that's a pause between the P sound and the T sound. 200 00:08:43,809 --> 00:08:45,650 That looks like a good word boundary. 201 00:08:45,650 --> 00:08:48,750 To a machine, that's a very good word boundary. 202 00:08:48,750 --> 00:08:50,440 It's not a word boundary for you. 203 00:08:50,440 --> 00:08:52,290 You know snapped is one word. 204 00:08:52,290 --> 00:08:56,090 And here comes "at." "At" is kind of blended into the T. So 205 00:08:56,090 --> 00:08:59,090 there's this physical signal doesn't even give you breaks 206 00:08:59,090 --> 00:09:01,800 where words separate from one another. 207 00:09:01,800 --> 00:09:07,230 It's kind of a continuous mix of breaks and silences. 208 00:09:07,230 --> 00:09:12,090 So here's to convince you that a silence carries incredible 209 00:09:12,090 --> 00:09:14,560 information in it. 210 00:09:14,560 --> 00:09:16,050 Let's see, make sure I have the volume. 211 00:09:16,050 --> 00:09:18,570 OK, so I'm going to play you this. 212 00:09:18,570 --> 00:09:23,850 This is a physical signal to your ear of the word "say." 213 00:09:23,850 --> 00:09:24,970 RECORDING: Say. 214 00:09:24,970 --> 00:09:27,330 PROFESSOR: OK. 215 00:09:27,330 --> 00:09:29,670 Yeah? 216 00:09:29,670 --> 00:09:31,460 I always worry because Tyler's an expert in this, and I'm 217 00:09:31,460 --> 00:09:33,250 always like, please, Tyler, don't 218 00:09:33,250 --> 00:09:35,310 embarrass me when I'm wrong. 219 00:09:35,310 --> 00:09:37,520 You don't have this pressure out there, but the teaching 220 00:09:37,520 --> 00:09:39,270 assistants are all experts in something or another. 221 00:09:39,270 --> 00:09:41,690 And then they know more often than I do on that topic, and 222 00:09:41,690 --> 00:09:42,860 we hit their topic in the course. 223 00:09:42,860 --> 00:09:45,910 I'm looking over there nervously. 224 00:09:45,910 --> 00:09:49,150 So here's "say." Now, they're going to take this thing and 225 00:09:49,150 --> 00:09:51,980 just separate this, just in the way you do a physical 226 00:09:51,980 --> 00:09:53,450 signal on a computer, just separate in time. 227 00:09:53,450 --> 00:09:55,290 They're just going to add a little bit of time. 228 00:09:55,290 --> 00:09:58,280 And what do you hear? 229 00:09:58,280 --> 00:09:59,880 RECORDING: Stay. 230 00:09:59,880 --> 00:10:04,390 PROFESSOR: The T sound that makes is simply adding silence 231 00:10:04,390 --> 00:10:06,010 here to produce that. 232 00:10:06,010 --> 00:10:07,140 Now, that's what you hear all the time. 233 00:10:07,140 --> 00:10:08,380 It's not a random choice. 234 00:10:08,380 --> 00:10:09,470 But isn't that amazing? 235 00:10:09,470 --> 00:10:13,240 That silence is as ultimately informative for your mind as 236 00:10:13,240 --> 00:10:16,060 actual language sounds themselves. 237 00:10:16,060 --> 00:10:18,200 All this is happening on the order of thousandths of a 238 00:10:18,200 --> 00:10:19,595 second, in bits of information. 239 00:10:22,130 --> 00:10:22,870 That's bad enough. 240 00:10:22,870 --> 00:10:24,670 Here's another amazingly tough thing. 241 00:10:24,670 --> 00:10:28,440 So people like to compare consonants that have a lot of 242 00:10:28,440 --> 00:10:31,060 similarities with some interesting differences. 243 00:10:31,060 --> 00:10:31,640 Ba and da. 244 00:10:31,640 --> 00:10:33,940 This is really comparing B versus D. It's throwing on the 245 00:10:33,940 --> 00:10:35,650 A just to have a vowel sound. 246 00:10:35,650 --> 00:10:38,260 So here, again, is a representation of what's 247 00:10:38,260 --> 00:10:39,820 coming to your ear. 248 00:10:39,820 --> 00:10:42,580 Notice that all the difference between the B and the D, these 249 00:10:42,580 --> 00:10:45,440 two consonants, all the physical differences occurring 250 00:10:45,440 --> 00:10:48,070 in 40,000ths of a second. 251 00:10:48,070 --> 00:10:51,210 40,000ths of a second is all the physical difference that 252 00:10:51,210 --> 00:10:52,990 you get as you hear these two things. 253 00:10:56,720 --> 00:10:59,660 RECORDING: Ba. 254 00:10:59,660 --> 00:11:00,440 Da. 255 00:11:00,440 --> 00:11:03,530 PROFESSOR: 40,000ths of a second, and yet you could hear 256 00:11:03,530 --> 00:11:06,980 the word bad, and you're not going bad, dab. 257 00:11:06,980 --> 00:11:08,790 Come on, that was thousandths of a second, right? 258 00:11:08,790 --> 00:11:11,220 And not only that, there'd be another word and another word 259 00:11:11,220 --> 00:11:11,860 in a sentence. 260 00:11:11,860 --> 00:11:14,490 That's why people use the word speech stream, and we like to 261 00:11:14,490 --> 00:11:16,970 think of it as a speech torrent. 262 00:11:16,970 --> 00:11:20,610 Phonemes, phonemes, phonemes, breaks, all garbled together 263 00:11:20,610 --> 00:11:23,480 in your mind as you back and constantly, instantly, and 264 00:11:23,480 --> 00:11:27,050 brilliantly figure out what you've heard. 265 00:11:27,050 --> 00:11:29,910 So let me give you another example because part of the 266 00:11:29,910 --> 00:11:34,630 challenge of this are phonemes occur in the context of words 267 00:11:34,630 --> 00:11:35,370 and sentences. 268 00:11:35,370 --> 00:11:37,800 So make sure I have good volume on this. 269 00:11:37,800 --> 00:11:40,080 OK, so let's do this first one. 270 00:11:40,080 --> 00:11:41,130 RECORDING: [INAUDIBLE]. 271 00:11:41,130 --> 00:11:42,334 PROFESSOR: What was that? 272 00:11:42,334 --> 00:11:42,806 AUDIENCE: [INAUDIBLE]. 273 00:11:42,806 --> 00:11:43,278 PROFESSOR: What? 274 00:11:43,278 --> 00:11:44,700 AUDIENCE: [INAUDIBLE]. 275 00:11:44,700 --> 00:11:47,510 PROFESSOR: OK. 276 00:11:47,510 --> 00:11:50,700 Here's the same thing, and a person is going to say this 277 00:11:50,700 --> 00:11:52,790 now all by itself. 278 00:11:52,790 --> 00:11:53,700 RECORDING: Little. 279 00:11:53,700 --> 00:11:54,680 PROFESSOR: You got that, right? 280 00:11:54,680 --> 00:11:56,526 OK. 281 00:11:56,526 --> 00:11:59,040 RECORDING: Mary saw the three little pigs in the corridor. 282 00:11:59,040 --> 00:12:01,460 PROFESSOR: OK, but here's the amazing thing. 283 00:12:01,460 --> 00:12:04,990 The first sound you heard, and I'll replay it, they took the 284 00:12:04,990 --> 00:12:08,170 word little, and they cut it out from the last 285 00:12:08,170 --> 00:12:10,020 sentence you heard. 286 00:12:10,020 --> 00:12:13,490 When little is said all by itself, what comes to your ear 287 00:12:13,490 --> 00:12:15,730 is literally the first thing you heard. 288 00:12:15,730 --> 00:12:20,120 Not this, because when you say a word in isolation, little, 289 00:12:20,120 --> 00:12:21,490 people say it differently. 290 00:12:21,490 --> 00:12:24,080 But we almost never talk like that. 291 00:12:24,080 --> 00:12:26,110 We almost always have a sentence. 292 00:12:26,110 --> 00:12:29,200 And it turns out the way we say things, and therefore, the 293 00:12:29,200 --> 00:12:33,130 way you hear things, is hugely influenced by what comes 294 00:12:33,130 --> 00:12:35,910 before it and what comes after it. 295 00:12:35,910 --> 00:12:37,810 Never mind things like the speed at which different 296 00:12:37,810 --> 00:12:40,920 people talk, the accent they talk, or the loudness of the 297 00:12:40,920 --> 00:12:42,810 background conversation. 298 00:12:42,810 --> 00:12:45,286 But just simply the fact that you're going to 299 00:12:45,286 --> 00:12:46,700 say little by itself. 300 00:12:46,700 --> 00:12:47,500 How does that work? 301 00:12:47,500 --> 00:12:48,620 It's amazing, right? 302 00:12:48,620 --> 00:12:49,340 Listen again. 303 00:12:49,340 --> 00:12:52,050 If you heard little all by itself, and it's exactly the 304 00:12:52,050 --> 00:12:53,300 same physical signal. 305 00:12:56,834 --> 00:12:57,302 Maybe it's not so-- 306 00:12:57,302 --> 00:12:58,710 RECORDING: [INAUDIBLE]. 307 00:12:58,710 --> 00:12:59,720 PROFESSOR: OK? 308 00:12:59,720 --> 00:13:01,132 Let me try that again. 309 00:13:01,132 --> 00:13:03,180 RECORDING: [INAUDIBLE]. 310 00:13:03,180 --> 00:13:06,350 PROFESSOR: That's exactly the same physical signal, exactly 311 00:13:06,350 --> 00:13:07,330 the same physical signal, as-- 312 00:13:07,330 --> 00:13:10,180 RECORDING: Mary saw the three little pigs in the corridor. 313 00:13:10,180 --> 00:13:11,650 PROFESSOR: What you hear easily as 314 00:13:11,650 --> 00:13:12,850 little is exactly that. 315 00:13:12,850 --> 00:13:13,910 Words in isolation-- 316 00:13:13,910 --> 00:13:15,250 and there's a great demonstration. 317 00:13:15,250 --> 00:13:18,900 If you hear a word cut out, the reason why it sounds like 318 00:13:18,900 --> 00:13:22,710 nothing is your mind is already preparing how to 319 00:13:22,710 --> 00:13:25,790 interpret that, given what you heard just before it, and also 320 00:13:25,790 --> 00:13:28,080 a little bit what you hear just after it. 321 00:13:28,080 --> 00:13:31,370 Your mind is constantly fixing up things because it knows 322 00:13:31,370 --> 00:13:33,240 what's going on, what's going into it, what's coming out. 323 00:13:33,240 --> 00:13:36,240 It's not because it just simply hears the word itself. 324 00:13:36,240 --> 00:13:38,480 If we lived in a world where people just say one word every 325 00:13:38,480 --> 00:13:41,270 half an hour, we could do this. 326 00:13:41,270 --> 00:13:43,320 In a world where we're talking to each other in sentences all 327 00:13:43,320 --> 00:13:45,190 the time, we have to do this. 328 00:13:47,870 --> 00:13:51,030 Here's another example of our brilliant auditory system for 329 00:13:51,030 --> 00:13:52,280 hearing these kinds of things. 330 00:13:52,280 --> 00:13:54,620 So again, these are representations of how this 331 00:13:54,620 --> 00:13:57,040 physical signal arrives at your ear. 332 00:13:57,040 --> 00:14:01,050 Here's the word bet, bee, boat, and bird. 333 00:14:01,050 --> 00:14:03,390 They all start with the same B sound. 334 00:14:03,390 --> 00:14:04,350 That's easy, right? 335 00:14:04,350 --> 00:14:06,020 But look what came to your ear. 336 00:14:06,020 --> 00:14:09,350 Look at this signal, this signal, this signal. 337 00:14:09,350 --> 00:14:09,950 Look at this one. 338 00:14:09,950 --> 00:14:11,950 How different does this look? 339 00:14:11,950 --> 00:14:15,900 It's different because what follows bird influences how 340 00:14:15,900 --> 00:14:19,250 this is said, but you can see that you can translate both of 341 00:14:19,250 --> 00:14:21,440 these into the B sound pretty easily. 342 00:14:21,440 --> 00:14:22,260 Now, look at these words. 343 00:14:22,260 --> 00:14:25,680 These all start with D. Look at how bet and debt look 344 00:14:25,680 --> 00:14:26,540 almost identical. 345 00:14:26,540 --> 00:14:29,000 We said it's only 40 milliseconds difference, 346 00:14:29,000 --> 00:14:31,050 40,000ths of a second difference that physically 347 00:14:31,050 --> 00:14:32,080 moved through your ear. 348 00:14:32,080 --> 00:14:34,920 But you can tell the word bet versus debt. 349 00:14:34,920 --> 00:14:37,030 Look at the word D, how different it looks 350 00:14:37,030 --> 00:14:38,840 from word to word. 351 00:14:38,840 --> 00:14:40,720 So your mind is constantly figuring 352 00:14:40,720 --> 00:14:42,120 out what you're hearing. 353 00:14:42,120 --> 00:14:45,370 The problem of invariance, and it's constantly coming to you 354 00:14:45,370 --> 00:14:47,650 in incredibly variable ways. 355 00:14:51,170 --> 00:14:54,550 So one of the tools we have, and an amazing human capacity, 356 00:14:54,550 --> 00:14:56,820 is what's called categorical perception. 357 00:14:56,820 --> 00:14:59,780 So we have all this huge range of physical sounds that can 358 00:14:59,780 --> 00:15:01,050 come to our ear. 359 00:15:01,050 --> 00:15:02,650 And kind of brilliantly, and you don't 360 00:15:02,650 --> 00:15:03,480 even think about it-- 361 00:15:03,480 --> 00:15:05,170 I mean, none of you go around bragging about your 362 00:15:05,170 --> 00:15:06,900 categorical perception abilities, right? 363 00:15:06,900 --> 00:15:09,070 Like when you go to spring break, right? 364 00:15:09,070 --> 00:15:11,340 And maybe some of you will go home, or you'll see friends, 365 00:15:11,340 --> 00:15:13,740 and you won't go, I have categorical perception. 366 00:15:13,740 --> 00:15:16,600 I try to be modest about it. 367 00:15:16,600 --> 00:15:21,290 But it's an amazing human talent, and essential because 368 00:15:21,290 --> 00:15:22,420 what it does is this. 369 00:15:22,420 --> 00:15:25,310 We hear this huge range of sounds, depending on accents, 370 00:15:25,310 --> 00:15:27,040 what comes before, what comes after. 371 00:15:27,040 --> 00:15:29,530 And we have to decide that's a B. And what you're going to do 372 00:15:29,530 --> 00:15:32,270 is take this huge range of things, and just go, boom. 373 00:15:32,270 --> 00:15:35,360 It's a B or a D, and that's all there is to it. 374 00:15:35,360 --> 00:15:38,290 So here's the way they do it. 375 00:15:38,290 --> 00:15:39,890 So categorical perception. 376 00:15:39,890 --> 00:15:41,480 Sounds can vary continuously. 377 00:15:41,480 --> 00:15:43,460 We showed you some of this continuity. 378 00:15:43,460 --> 00:15:45,060 In this experiment, on purpose, they're going to vary 379 00:15:45,060 --> 00:15:48,420 sounds in a very continuous, physical way. 380 00:15:48,420 --> 00:15:53,800 But in our heads, for ba and da here, in our heads, all the 381 00:15:53,800 --> 00:15:56,290 stuff that's over here, even though they're very different 382 00:15:56,290 --> 00:15:58,690 one from the other at a physical, specific level, 383 00:15:58,690 --> 00:15:59,700 we'll say, ba. 384 00:15:59,700 --> 00:16:00,360 I'm done with it. 385 00:16:00,360 --> 00:16:03,250 We're going to put it in one category for interpretation. 386 00:16:03,250 --> 00:16:05,750 And you're going to have a pretty sharp boundary here. 387 00:16:05,750 --> 00:16:08,510 And then everything over here, all these physical signals, 388 00:16:08,510 --> 00:16:09,780 you're going to call pa. 389 00:16:09,780 --> 00:16:12,020 And so you're not going to spend a lot of time going, 390 00:16:12,020 --> 00:16:15,720 that was a one third ba, 2/3 pa, probability. 391 00:16:15,720 --> 00:16:16,690 You couldn't do that, right? 392 00:16:16,690 --> 00:16:17,690 Because you couldn't get through a 393 00:16:17,690 --> 00:16:18,680 word, nevermind a sentence. 394 00:16:18,680 --> 00:16:21,760 You're going to instantly group huge numbers of things 395 00:16:21,760 --> 00:16:24,520 that are different from one another into two categories 396 00:16:24,520 --> 00:16:26,470 that need to be separated. 397 00:16:26,470 --> 00:16:28,360 So here's a kind of experiment they do. 398 00:16:28,360 --> 00:16:29,670 I'll just give you the feeling of it. 399 00:16:29,670 --> 00:16:32,070 Here's what they're varying, constant units. 400 00:16:32,070 --> 00:16:35,350 Constant units, every stimulus here is different. 401 00:16:35,350 --> 00:16:38,335 But every time you hear ba, and they're constantly going 402 00:16:38,335 --> 00:16:40,900 to vary something by its physical property, you always 403 00:16:40,900 --> 00:16:45,910 call it a B. And then something happens, in about 20 404 00:16:45,910 --> 00:16:49,360 milliseconds of information, and boom, you always call it a 405 00:16:49,360 --> 00:16:53,070 P. So change, change, change, change, change, in the 406 00:16:53,070 --> 00:16:56,340 physical signal, you call it one category. 407 00:16:56,340 --> 00:16:58,150 A little bit more change, boom. 408 00:16:58,150 --> 00:16:59,540 It's the other category. 409 00:16:59,540 --> 00:17:01,940 And you keep changing, but for you, it's always a perfectly 410 00:17:01,940 --> 00:17:06,079 good P, even though every one of those are different. 411 00:17:06,079 --> 00:17:10,310 So it's an amazing fundamental capacity to take a huge, and, 412 00:17:10,310 --> 00:17:13,260 for all practical purposes, an infinite variety of inputs and 413 00:17:13,260 --> 00:17:17,520 say it's a B or a P if that's the world I'm working in. 414 00:17:17,520 --> 00:17:19,190 Syntax. 415 00:17:19,190 --> 00:17:21,619 That's another way in which we understand things, the way 416 00:17:21,619 --> 00:17:23,010 that words are organized and the order. 417 00:17:23,010 --> 00:17:25,839 So we could say, "The model embraced the designer and the 418 00:17:25,839 --> 00:17:27,569 photographer." Imagine somebody saying to this. 419 00:17:27,569 --> 00:17:30,240 But then they complete the sentence, "The model embraced 420 00:17:30,240 --> 00:17:33,070 the designer and the photographer laughed." 421 00:17:33,070 --> 00:17:35,890 So people who study syntax really are interested in what 422 00:17:35,890 --> 00:17:38,180 happens in your mind as you hear, "The model embraced the 423 00:17:38,180 --> 00:17:40,600 designer and the photographer," and some big 424 00:17:40,600 --> 00:17:42,420 group hug is going on, right? 425 00:17:42,420 --> 00:17:45,130 And then all of a sudden, you get this word laughed, and you 426 00:17:45,130 --> 00:17:47,210 have to rearrange the elements in your mind. 427 00:17:47,210 --> 00:17:49,020 That's what syntax is letting you do, to say, oh, the 428 00:17:49,020 --> 00:17:50,620 meaning is really quite different. 429 00:17:50,620 --> 00:17:53,560 There's only one hug going on, and one person laughing at 430 00:17:53,560 --> 00:17:54,210 them, right? 431 00:17:54,210 --> 00:17:58,090 But the meaning over time as somebody talks to you set up, 432 00:17:58,090 --> 00:18:00,030 you're thinking this, boom. 433 00:18:00,030 --> 00:18:05,150 Because you understand syntax, you understand what happens. 434 00:18:05,150 --> 00:18:07,870 Semantics are kind of more straightforward than how we 435 00:18:07,870 --> 00:18:09,190 usually think about them. 436 00:18:09,190 --> 00:18:12,880 They're the meaning of words or sentences, morphemes. 437 00:18:12,880 --> 00:18:14,640 And we can understand semantics even when the 438 00:18:14,640 --> 00:18:16,850 sentence is nonsense. "Colorless green ideas sleep 439 00:18:16,850 --> 00:18:19,330 furiously" is a famous example. 440 00:18:19,330 --> 00:18:21,930 We can understand semantics even in bad grammatical 441 00:18:21,930 --> 00:18:23,020 sentences, right? 442 00:18:23,020 --> 00:18:27,050 "Fastly eat dinner, ballgame start soon." Your fifth grade 443 00:18:27,050 --> 00:18:31,190 teacher would be up in arms to hear that, but you understand. 444 00:18:31,190 --> 00:18:31,660 Eat now. 445 00:18:31,660 --> 00:18:33,690 Go see the ball game. 446 00:18:33,690 --> 00:18:36,390 So we get through a lot of stuff to get semantics. 447 00:18:36,390 --> 00:18:37,460 And we can see interactions. 448 00:18:37,460 --> 00:18:40,820 I stole this example from Ted Gibson because it took me 20 449 00:18:40,820 --> 00:18:43,170 minutes to figure out what the sentence means. 450 00:18:43,170 --> 00:18:44,420 You're probably faster than I am. 451 00:18:48,791 --> 00:18:50,600 Are you OK? 452 00:18:50,600 --> 00:18:52,060 I'm like the old man. 453 00:18:52,060 --> 00:18:53,820 Where's the missing words? 454 00:18:53,820 --> 00:18:56,730 The old man the boats. 455 00:18:56,730 --> 00:18:59,270 So this is how you have to parse up the sentence. 456 00:18:59,270 --> 00:19:00,450 It's not always obvious. 457 00:19:00,450 --> 00:19:02,240 People who study language love these things, where people are 458 00:19:02,240 --> 00:19:03,580 all confused. 459 00:19:03,580 --> 00:19:05,320 Most of our lives, we don't go through that much confusion. 460 00:19:05,320 --> 00:19:07,470 But there's some fun ones, sort of like the visual 461 00:19:07,470 --> 00:19:10,340 illusions, to point out how meaning and syntax can 462 00:19:10,340 --> 00:19:11,590 interact as you figure out things. 463 00:19:11,590 --> 00:19:12,920 Here's another example. 464 00:19:12,920 --> 00:19:15,330 Jay Leno talked about sex with Lindsey Lohan. 465 00:19:15,330 --> 00:19:17,350 OK, now wait a minute. 466 00:19:17,350 --> 00:19:21,845 Did I miss that excellent episode of Jay Leno, or was 467 00:19:21,845 --> 00:19:23,730 she on the show, and talking about-- she was saying I'd 468 00:19:23,730 --> 00:19:25,480 rather not talk about my recent conviction. 469 00:19:25,480 --> 00:19:29,170 I'd rather talk about something less controversial. 470 00:19:29,170 --> 00:19:30,720 So semantic. 471 00:19:30,720 --> 00:19:31,900 All these things are constantly 472 00:19:31,900 --> 00:19:32,810 interacting in your mind. 473 00:19:32,810 --> 00:19:34,740 It's kind of amazing when you think about that, right? 474 00:19:34,740 --> 00:19:36,090 We said phonology's amazing. 475 00:19:36,090 --> 00:19:37,910 Semantics, syntax, boom. 476 00:19:37,910 --> 00:19:39,050 They're all happening in you. 477 00:19:39,050 --> 00:19:40,220 And none of you are sitting there, 478 00:19:40,220 --> 00:19:42,830 going, just do phonology. 479 00:19:42,830 --> 00:19:44,570 Please don't ask me to do semantics. 480 00:19:44,570 --> 00:19:45,910 We just had midterms, right? 481 00:19:45,910 --> 00:19:48,570 Brilliant. 482 00:19:48,570 --> 00:19:50,780 So one of the ways that people try to convince themselves 483 00:19:50,780 --> 00:19:52,530 that these things are separable and gives a little 484 00:19:52,530 --> 00:19:54,990 bit more insight is Evoked Response Potentials. 485 00:19:54,990 --> 00:19:57,560 Those are these things that you can measure on infants or 486 00:19:57,560 --> 00:20:00,910 adults that measure electrical activity in milliseconds and 487 00:20:00,910 --> 00:20:04,610 the speed of language processing, surface electrodes 488 00:20:04,610 --> 00:20:10,260 that give you an index of a few hundred thousand neurons. 489 00:20:10,260 --> 00:20:13,280 And this is an example you saw before, actually, earlier in 490 00:20:13,280 --> 00:20:15,280 the course, the so-called N400. 491 00:20:15,280 --> 00:20:18,590 So N means whether the wave is going up or 492 00:20:18,590 --> 00:20:20,900 down, negative or positive. 493 00:20:20,900 --> 00:20:24,200 400 means that it occurs about 400 milliseconds, about half a 494 00:20:24,200 --> 00:20:26,410 second, after the relevant event. 495 00:20:26,410 --> 00:20:31,380 So here is this, let's see, it was his first day at work. 496 00:20:31,380 --> 00:20:32,280 That's the baseline. 497 00:20:32,280 --> 00:20:34,550 He spread the warm bread with socks. 498 00:20:34,550 --> 00:20:35,360 Oh my gosh, socks. 499 00:20:35,360 --> 00:20:36,160 Semantically bad. 500 00:20:36,160 --> 00:20:38,760 And here comes the N400. 501 00:20:38,760 --> 00:20:42,080 And the control condition is you throw up this unexpected 502 00:20:42,080 --> 00:20:45,900 word, shoes, that's weird, but not semantically, and you get 503 00:20:45,900 --> 00:20:46,890 quite a different response. 504 00:20:46,890 --> 00:20:50,520 So here's an N400 that seems to simply be about semantic 505 00:20:50,520 --> 00:20:53,690 expectation or congruence. 506 00:20:53,690 --> 00:20:57,110 How about if you mess up syntax? 507 00:20:57,110 --> 00:21:02,780 The spoiled child throw the toys on the box. 508 00:21:02,780 --> 00:21:06,460 Then you get a response at about 600 milliseconds to 509 00:21:06,460 --> 00:21:08,270 syntactic incongruity. 510 00:21:08,270 --> 00:21:11,740 So people, this is just more evidence that in the brain, 511 00:21:11,740 --> 00:21:14,720 meaning or semantics and syntax or something about word 512 00:21:14,720 --> 00:21:20,470 order are processed somewhat differently in time and place. 513 00:21:20,470 --> 00:21:21,600 Pragmatics is kind of fun. 514 00:21:21,600 --> 00:21:23,410 It's practical understanding. 515 00:21:23,410 --> 00:21:24,660 The old joke, do you know what time it is? 516 00:21:24,660 --> 00:21:25,990 And the person says, yes. 517 00:21:25,990 --> 00:21:27,705 They're messing with your sense of pragmatics. 518 00:21:30,380 --> 00:21:31,800 Two negatives make a positive. 519 00:21:31,800 --> 00:21:32,590 Saying, yeah, yeah. 520 00:21:32,590 --> 00:21:35,750 I've heard that one before, earlier in the lecture. 521 00:21:35,750 --> 00:21:37,860 Now, here's something kind of interesting, again, which is 522 00:21:37,860 --> 00:21:38,195 remarkable. 523 00:21:38,195 --> 00:21:40,920 And if you didn't do the experiment, you couldn't know 524 00:21:40,920 --> 00:21:42,450 that our mind is like this. 525 00:21:42,450 --> 00:21:45,370 Because you wouldn't do things like this because it sounds 526 00:21:45,370 --> 00:21:48,090 too ridiculous, but your mind does it all the time. 527 00:21:48,090 --> 00:21:51,300 So we're going to think about the word "bugs." And I have to 528 00:21:51,300 --> 00:21:53,570 set you up a little bit with paradigms you've heard before, 529 00:21:53,570 --> 00:21:55,490 but just remind you of these things. 530 00:21:55,490 --> 00:21:59,660 So one kind of task that psychologists like to use to 531 00:21:59,660 --> 00:22:01,410 think about how people process words is a 532 00:22:01,410 --> 00:22:03,850 lexical decision task. 533 00:22:03,850 --> 00:22:07,790 All you're deciding is whether a word is a real word or a 534 00:22:07,790 --> 00:22:09,340 nonsense word. 535 00:22:09,340 --> 00:22:10,580 So doctor is real. 536 00:22:10,580 --> 00:22:11,530 Poctor is not. 537 00:22:11,530 --> 00:22:12,950 Spy is a real word. 538 00:22:12,950 --> 00:22:15,250 This spelling is not a real word. 539 00:22:15,250 --> 00:22:17,700 So real word, not a real word. 540 00:22:17,700 --> 00:22:20,420 We also talked about one other idea early in the course, that 541 00:22:20,420 --> 00:22:24,440 if, prior to processing a word like doctor, you get an 542 00:22:24,440 --> 00:22:27,500 unrelated word or a related word, you process doctor 543 00:22:27,500 --> 00:22:30,120 faster if you had a related word before it. 544 00:22:30,120 --> 00:22:30,870 Semantic priming. 545 00:22:30,870 --> 00:22:33,260 The ideas about nurse overlap a lot with 546 00:22:33,260 --> 00:22:34,840 the ideas about doctor. 547 00:22:34,840 --> 00:22:36,150 And seeing this word before makes you 548 00:22:36,150 --> 00:22:37,810 process this word faster. 549 00:22:37,810 --> 00:22:39,490 So you need those two things in mind. 550 00:22:39,490 --> 00:22:40,730 What was the person doing? 551 00:22:40,730 --> 00:22:42,110 Is it a real word or not? 552 00:22:42,110 --> 00:22:45,060 And you're going to mess with what's in their mind before 553 00:22:45,060 --> 00:22:46,980 that, related or unrelated. 554 00:22:46,980 --> 00:22:49,280 And here's the experiment. 555 00:22:49,280 --> 00:22:51,750 So you would hear, over headphones, something like 556 00:22:51,750 --> 00:22:52,730 this, as an example. 557 00:22:52,730 --> 00:22:55,760 "Rumor has it that for years the government building had 558 00:22:55,760 --> 00:22:56,910 been plagued with problems." Now, 559 00:22:56,910 --> 00:22:58,510 here's a critical sentence. 560 00:22:58,510 --> 00:23:01,560 "The man was not surprised when he found several spiders, 561 00:23:01,560 --> 00:23:05,330 roaches, and other bugs in the corner of his room." 562 00:23:05,330 --> 00:23:07,550 So there's two senses of the word, at least two meanings of 563 00:23:07,550 --> 00:23:08,740 the word bug, right? 564 00:23:08,740 --> 00:23:12,870 The insect you don't want in your soup, or the microphone 565 00:23:12,870 --> 00:23:14,490 that somebody slipped into your room to listen to 566 00:23:14,490 --> 00:23:15,210 what's going on. 567 00:23:15,210 --> 00:23:18,350 Two different meanings for the word bug. 568 00:23:18,350 --> 00:23:20,800 This is obviously about the insect. 569 00:23:20,800 --> 00:23:23,210 So the person is hearing this over headphones, and on a 570 00:23:23,210 --> 00:23:27,150 computer monitor in front of them, after they hear the word 571 00:23:27,150 --> 00:23:31,600 bugs here, they see, for a lexical decision, the word 572 00:23:31,600 --> 00:23:35,870 "ant," which is related to this meaning, or "spy," which 573 00:23:35,870 --> 00:23:38,120 is related to the other meaning that's not relevant 574 00:23:38,120 --> 00:23:41,110 for here, or "sew," which is the control condition. 575 00:23:41,110 --> 00:23:42,990 We'll ignore that because it's just a control condition. 576 00:23:42,990 --> 00:23:44,140 I'll ignore that for now. 577 00:23:44,140 --> 00:23:47,220 So you're making a lexical decision now on the related 578 00:23:47,220 --> 00:23:49,680 meaning or the unrelated meaning. 579 00:23:49,680 --> 00:23:51,760 And here's what they find. 580 00:23:51,760 --> 00:23:55,200 If it's the related meaning, and you only have about a half 581 00:23:55,200 --> 00:23:57,960 second from when that came on to when you had to do this 582 00:23:57,960 --> 00:23:59,770 task, so you saw the word bug and here comes 583 00:23:59,770 --> 00:24:03,290 this, you're faster. 584 00:24:03,290 --> 00:24:07,100 But if you get the unrelated meaning within a half a second 585 00:24:07,100 --> 00:24:11,240 of processing the word, you're also faster. 586 00:24:11,240 --> 00:24:14,280 What this means is, your mind has done exactly what you 587 00:24:14,280 --> 00:24:15,800 would think it wouldn't do. 588 00:24:15,800 --> 00:24:18,520 Your mind has looked up in your brain, and in your 589 00:24:18,520 --> 00:24:22,720 knowledge of vocabulary, every meaning of the word. 590 00:24:22,720 --> 00:24:25,310 Even though the sentence is clearly setting you up for the 591 00:24:25,310 --> 00:24:30,010 word, the insect meaning, every meaning of your word is 592 00:24:30,010 --> 00:24:31,440 turned on and available to you. 593 00:24:31,440 --> 00:24:33,290 Your mind does the opposite of what you might think. 594 00:24:33,290 --> 00:24:34,820 You might think, well, I know-- 595 00:24:34,820 --> 00:24:36,920 let's look at the sentence. 596 00:24:36,920 --> 00:24:39,460 I know, once I get spiders, roaches, and bugs. 597 00:24:39,460 --> 00:24:42,010 By here, you know you're in the insect world, not in the 598 00:24:42,010 --> 00:24:43,950 world of spies, right? 599 00:24:43,950 --> 00:24:50,170 But your mind, even then, looks up every possible word. 600 00:24:50,170 --> 00:24:53,840 Because it's cheaper for the mind to look up every word 601 00:24:53,840 --> 00:24:57,360 than to start to decide what the appropriate word is. 602 00:24:57,360 --> 00:25:01,780 And then, if you wait another second and a half, you're only 603 00:25:01,780 --> 00:25:04,900 fast for the selected meaning. 604 00:25:04,900 --> 00:25:06,510 And now you're slowed down for the one 605 00:25:06,510 --> 00:25:08,100 that's not context relevant. 606 00:25:08,100 --> 00:25:11,030 So your mind looks up everything all the time. 607 00:25:11,030 --> 00:25:13,310 Every meaning of every word you know. 608 00:25:13,310 --> 00:25:15,320 Every time that word pops up, it seems like your mind looks 609 00:25:15,320 --> 00:25:18,650 up every meaning, and then the rest of your mind selects out 610 00:25:18,650 --> 00:25:20,720 the one that's relevant and shuts down the 611 00:25:20,720 --> 00:25:22,150 ones that are not. 612 00:25:22,150 --> 00:25:22,900 But you wouldn't think that. 613 00:25:22,900 --> 00:25:24,280 You would think, maybe I'll just get the one I need. 614 00:25:24,280 --> 00:25:24,955 I'm not going to get everything. 615 00:25:24,955 --> 00:25:27,110 It's like, I'm not going to put all my clothes on, walk 616 00:25:27,110 --> 00:25:28,960 outside, and take off everything that's not relevant 617 00:25:28,960 --> 00:25:30,620 for the weather, right? 618 00:25:30,620 --> 00:25:34,070 It seems like a really inefficient way to get 619 00:25:34,070 --> 00:25:34,970 dressed, right? 620 00:25:34,970 --> 00:25:36,760 But that's not the way your mind is. 621 00:25:36,760 --> 00:25:39,950 Your mind is cheaper and more efficient to look up every 622 00:25:39,950 --> 00:25:42,410 meaning every time, and then pick the right one. 623 00:25:42,410 --> 00:25:45,400 It's more efficient, and that's how people do it. 624 00:25:45,400 --> 00:25:47,850 So people use this word exhaustive lexical access. 625 00:25:47,850 --> 00:25:50,670 I look up every meaning of a word, and then I'll pick out 626 00:25:50,670 --> 00:25:51,920 the correct one. 627 00:25:56,720 --> 00:26:00,920 Another interesting aspect that could be brought into 628 00:26:00,920 --> 00:26:02,700 pragmatics, and we'll talk a little bit more about this 629 00:26:02,700 --> 00:26:04,860 later in the course, but emotional intonation. 630 00:26:04,860 --> 00:26:07,910 And it turns out where it's almost all language processes 631 00:26:07,910 --> 00:26:09,620 are left dominance as we talked about many 632 00:26:09,620 --> 00:26:11,140 times in the course. 633 00:26:11,140 --> 00:26:15,980 One stream of processing language, both visual and 634 00:26:15,980 --> 00:26:18,570 auditory, is right hemisphere dependent. 635 00:26:18,570 --> 00:26:20,690 And that's emotional intonation. 636 00:26:20,690 --> 00:26:23,620 And that brings us to our reading for 637 00:26:23,620 --> 00:26:26,030 today, from Oliver Sacks. 638 00:26:26,030 --> 00:26:28,410 And I have to say, I think Oliver Sacks is a phenomenal 639 00:26:28,410 --> 00:26:31,280 author, but there's always been this sense of some of 640 00:26:31,280 --> 00:26:33,920 these stories are just a bit too true to be-- just a bit 641 00:26:33,920 --> 00:26:34,870 cute, or whatever it is. 642 00:26:34,870 --> 00:26:39,920 And so for years, I taught from this story, and I 643 00:26:39,920 --> 00:26:40,860 believed it's likely true. 644 00:26:40,860 --> 00:26:42,270 But I thought, well, it's just a little cute. 645 00:26:42,270 --> 00:26:44,550 And then came an experiment that showed it's not only 646 00:26:44,550 --> 00:26:46,650 cute, but it's exactly correct. 647 00:26:46,650 --> 00:26:53,680 So for this, you appreciate this a bit more if you know a 648 00:26:53,680 --> 00:26:55,220 couple things about Ronald Reagan, who was 649 00:26:55,220 --> 00:26:56,400 president in the 1980s. 650 00:26:56,400 --> 00:27:00,380 So what do you guys know about Ronald Reagan? 651 00:27:00,380 --> 00:27:01,702 What party? 652 00:27:01,702 --> 00:27:02,200 AUDIENCE: Republican. 653 00:27:02,200 --> 00:27:03,540 PROFESSOR: There you go. 654 00:27:03,540 --> 00:27:06,710 Was he considered a good communicator? 655 00:27:06,710 --> 00:27:07,670 AUDIENCE: Yes. 656 00:27:07,670 --> 00:27:08,150 PROFESSOR: Yes. 657 00:27:08,150 --> 00:27:09,750 He was considered-- you know, you can have all kinds of 658 00:27:09,750 --> 00:27:11,260 views on Ronald Reagan's things. 659 00:27:11,260 --> 00:27:13,270 The public said, he's an awesome communicator. 660 00:27:13,270 --> 00:27:15,322 In fact, Barack Obama said he would like to communicate like 661 00:27:15,322 --> 00:27:16,880 Ronald Reagan. 662 00:27:16,880 --> 00:27:18,930 Whether that's to get Republican votes or not, 663 00:27:18,930 --> 00:27:20,210 that's your judgment. 664 00:27:20,210 --> 00:27:22,520 But he was considered an excellent communicator. 665 00:27:22,520 --> 00:27:27,280 Was he considered, by and large, to be an extremely 666 00:27:27,280 --> 00:27:31,530 analytic thinker? 667 00:27:31,530 --> 00:27:32,680 He might have been. 668 00:27:32,680 --> 00:27:33,210 I don't know him. 669 00:27:33,210 --> 00:27:34,200 But not so much. 670 00:27:34,200 --> 00:27:36,225 Now, part of this is the prejudice or not, but he was 671 00:27:36,225 --> 00:27:41,630 from California, and he was an actor before he became 672 00:27:41,630 --> 00:27:43,200 president, or the governor president. 673 00:27:43,200 --> 00:27:47,290 He also had some degree of-- 674 00:27:47,290 --> 00:27:49,040 well, he ultimately got Alzheimer's disease. 675 00:27:49,040 --> 00:27:50,750 It's a question about later in his administration, whether he 676 00:27:50,750 --> 00:27:52,690 was already working his way towards that. 677 00:27:52,690 --> 00:27:53,810 So anyway, complicated things. 678 00:27:53,810 --> 00:27:55,890 So he was a master communicator, but not 679 00:27:55,890 --> 00:28:00,410 necessarily the Barack Obama, Bill Clinton, Jimmy Carter 680 00:28:00,410 --> 00:28:04,450 version of an analytic power, is the general perception. 681 00:28:04,450 --> 00:28:05,670 You never know whether these are right or 682 00:28:05,670 --> 00:28:08,050 wrong for the person. 683 00:28:08,050 --> 00:28:10,840 But in the story, listening to the president's speech, are 684 00:28:10,840 --> 00:28:13,220 patients with aphasia that Oliver Sacks described, and 685 00:28:13,220 --> 00:28:16,460 he's getting laughter as they're watching his speech. 686 00:28:16,460 --> 00:28:20,100 And what happens is, some of the people with a left 687 00:28:20,100 --> 00:28:21,940 hemisphere lesion-- so you have a language problem. 688 00:28:21,940 --> 00:28:24,980 We'll see a video of that pretty shortly. 689 00:28:24,980 --> 00:28:30,740 They're laughing because they think that the way he's 690 00:28:30,740 --> 00:28:31,600 talking and his facial 691 00:28:31,600 --> 00:28:34,030 expressions, they find hilarious. 692 00:28:34,030 --> 00:28:36,510 Now, why do they find it hilarious? 693 00:28:36,510 --> 00:28:38,370 They have damage to the parts of the brain that help them 694 00:28:38,370 --> 00:28:40,570 understand the content of his message on the left 695 00:28:40,570 --> 00:28:41,450 hemisphere. 696 00:28:41,450 --> 00:28:44,260 And here's what Sacks thinks is going on. 697 00:28:44,260 --> 00:28:46,370 "The feelings I have, which all of us who work closely 698 00:28:46,370 --> 00:28:51,660 with aphasics have, is that you cannot lie to an aphasic. 699 00:28:51,660 --> 00:28:56,050 He cannot grasp your words, and so be deceived by them. 700 00:28:56,050 --> 00:28:58,820 But what he grasps, he grasps with infallible precision, 701 00:28:58,820 --> 00:29:01,610 namely, the expression that goes with the words, that 702 00:29:01,610 --> 00:29:04,920 total spontaneous, involuntary expressiveness which can never 703 00:29:04,920 --> 00:29:09,250 be simulated or faked, or words alone can hide all 704 00:29:09,250 --> 00:29:10,950 sometimes too easily." 705 00:29:10,950 --> 00:29:14,890 So when you give a very public speech, especially under tough 706 00:29:14,890 --> 00:29:17,960 circumstances, that presidents sometimes have to do, we 707 00:29:17,960 --> 00:29:20,160 sometimes think there's a tension between exactly what 708 00:29:20,160 --> 00:29:23,260 they're saying and exactly what they're thinking. 709 00:29:23,260 --> 00:29:25,560 And what they feel they need to say, and exactly what they 710 00:29:25,560 --> 00:29:27,340 know is behind the scenes. 711 00:29:27,340 --> 00:29:31,070 And so the idea is that these aphasics, they were saying 712 00:29:31,070 --> 00:29:33,570 this guy obviously doesn't mean what he's saying. 713 00:29:33,570 --> 00:29:34,530 Look at his face. 714 00:29:34,530 --> 00:29:35,160 Look at his tone. 715 00:29:35,160 --> 00:29:38,780 I don't know what he's saying, but it's hilarious, how he's 716 00:29:38,780 --> 00:29:41,800 masking his face and speaking in a funny tone to tell 717 00:29:41,800 --> 00:29:44,510 something he truly doesn't believe. 718 00:29:44,510 --> 00:29:45,860 That's their interpretation. 719 00:29:45,860 --> 00:29:47,850 And yet, he has an opposite patient, a patient with a 720 00:29:47,850 --> 00:29:48,900 right hemisphere lesion. 721 00:29:48,900 --> 00:29:50,750 We said that's the side of the hemisphere that seems 722 00:29:50,750 --> 00:29:53,920 important for facial expressions and emotional 723 00:29:53,920 --> 00:29:54,780 intonation. 724 00:29:54,780 --> 00:29:58,520 And she complains about the logic of the case he's making, 725 00:29:58,520 --> 00:29:59,910 as if having-- 726 00:29:59,910 --> 00:30:01,430 normally, when we talk to somebody, it's both. 727 00:30:01,430 --> 00:30:03,160 Left hemisphere's getting the content, 728 00:30:03,160 --> 00:30:04,360 analyzing the content. 729 00:30:04,360 --> 00:30:06,450 Right hemisphere, something about the intonation. 730 00:30:06,450 --> 00:30:07,855 True or not true? 731 00:30:07,855 --> 00:30:10,210 Are their eyes like this, and they can't even face us as 732 00:30:10,210 --> 00:30:12,705 they tell us something they know is false. 733 00:30:12,705 --> 00:30:14,920 But these patients, maybe because they have one channel 734 00:30:14,920 --> 00:30:18,385 of information knocked out because of injury, they become 735 00:30:18,385 --> 00:30:21,050 hypersensitive to the other one. 736 00:30:21,050 --> 00:30:24,420 So I thought, well, that sounds fantastically 737 00:30:24,420 --> 00:30:26,570 interesting, but is that really true? 738 00:30:26,570 --> 00:30:28,870 So here in Boston, they did a study with a large number of 739 00:30:28,870 --> 00:30:32,650 patients that says they had superior identification of 740 00:30:32,650 --> 00:30:35,550 people who are lying to you-- 741 00:30:35,550 --> 00:30:38,040 they had made video clips and audio clips of people who are 742 00:30:38,040 --> 00:30:39,520 lying to you-- 743 00:30:39,520 --> 00:30:42,400 if they had a left hemisphere lesion. 744 00:30:42,400 --> 00:30:44,870 So this is a paper. 745 00:30:44,870 --> 00:30:46,180 So here's the two examples. 746 00:30:46,180 --> 00:30:47,880 So they have an example. 747 00:30:47,880 --> 00:30:49,350 Let's pick this one. 748 00:30:49,350 --> 00:30:51,090 Where both, you see just a facial 749 00:30:51,090 --> 00:30:52,980 expression of a person talking. 750 00:30:52,980 --> 00:30:54,800 The voice is turned down. 751 00:30:54,800 --> 00:30:58,930 Your job is to decide whether a person is lying or not. 752 00:30:58,930 --> 00:31:00,260 And some videos they're lying. 753 00:31:00,260 --> 00:31:01,470 Some videos they're not. 754 00:31:01,470 --> 00:31:03,640 So how would you do? 755 00:31:03,640 --> 00:31:05,840 I don't know how you would do, but I can tell you how a group 756 00:31:05,840 --> 00:31:07,790 of Harvard undergraduates did. 757 00:31:07,790 --> 00:31:11,390 50% is chance, and here's how they did. 758 00:31:11,390 --> 00:31:13,410 That was one of their control groups. 759 00:31:13,410 --> 00:31:16,160 And, in fact, for studies like this, they brought in many, 760 00:31:16,160 --> 00:31:21,310 many kinds of people to ask whether anybody is better. 761 00:31:21,310 --> 00:31:24,240 Everybody's pretty much terrible at directly telling 762 00:31:24,240 --> 00:31:25,270 whether a lie is going on. 763 00:31:25,270 --> 00:31:27,250 Now, these are video clips of people you don't know in 764 00:31:27,250 --> 00:31:28,410 circumstances you don't know. 765 00:31:28,410 --> 00:31:29,370 That could matter. 766 00:31:29,370 --> 00:31:31,660 But everybody's terrible at that. 767 00:31:31,660 --> 00:31:33,440 Policemen are terrible. 768 00:31:33,440 --> 00:31:35,150 FBI agents are terrible. 769 00:31:35,150 --> 00:31:37,720 The only group that seems to be above chance, and not much 770 00:31:37,720 --> 00:31:40,640 above it, are Secret Service agents. 771 00:31:40,640 --> 00:31:43,140 So if you're friend with a Secret Service agent, and you 772 00:31:43,140 --> 00:31:45,740 want to deceive them, keep in mind that they seem to be 773 00:31:45,740 --> 00:31:46,380 above chance. 774 00:31:46,380 --> 00:31:47,530 They're not awesome, but they're above chance. 775 00:31:47,530 --> 00:31:50,030 But look who's doing better than everybody, patients with 776 00:31:50,030 --> 00:31:52,380 the left hemisphere lesions. 777 00:31:52,380 --> 00:31:55,610 And the interpretation is, all the content 778 00:31:55,610 --> 00:31:57,040 of the lie is gone. 779 00:31:57,040 --> 00:32:00,550 All they see is your expression, or your expression 780 00:32:00,550 --> 00:32:01,940 and intonation. 781 00:32:01,940 --> 00:32:04,400 And because that's all they have to go on, they can tell 782 00:32:04,400 --> 00:32:07,340 more when you have the discomfort of lying than a 783 00:32:07,340 --> 00:32:10,800 person who's partly persuaded by hearing the message you're 784 00:32:10,800 --> 00:32:12,380 sending as you talk. 785 00:32:12,380 --> 00:32:14,820 So I thought this was an overly cute example, but it 786 00:32:14,820 --> 00:32:18,170 turns out to be exactly replicable in a full study. 787 00:32:18,170 --> 00:32:19,420 Any questions about that? 788 00:32:21,970 --> 00:32:24,120 OK. 789 00:32:24,120 --> 00:32:25,690 So let's talk a little bit about the 790 00:32:25,690 --> 00:32:26,840 brain basis of language. 791 00:32:26,840 --> 00:32:28,680 We've talked a little bit about-- 792 00:32:28,680 --> 00:32:31,910 we know that if you have damage here, you have Broca's 793 00:32:31,910 --> 00:32:33,240 aphasia on the left hemisphere, 794 00:32:33,240 --> 00:32:35,390 trouble producing language. 795 00:32:35,390 --> 00:32:37,610 Damage here, Wernicke's aphasia, trouble 796 00:32:37,610 --> 00:32:38,860 comprehending language. 797 00:32:42,010 --> 00:32:45,070 To a first approximation, and there's a lot of research that 798 00:32:45,070 --> 00:32:47,960 has made this much more complicated, but a first 799 00:32:47,960 --> 00:32:50,190 approximation, the lesions are in frontal 800 00:32:50,190 --> 00:32:52,120 cortex or temporal cortex. 801 00:32:52,120 --> 00:32:54,730 The speech in these patients are what's called non-fluent 802 00:32:54,730 --> 00:32:55,530 or telegraphic. 803 00:32:55,530 --> 00:32:57,690 They get single words out but have a hard time with anything 804 00:32:57,690 --> 00:32:58,390 like a sentence. 805 00:32:58,390 --> 00:33:00,820 It can be very frustrating for these patients. 806 00:33:00,820 --> 00:33:02,520 Wernicke's patients seem much happier. 807 00:33:02,520 --> 00:33:03,650 You'll see a film in a moment. 808 00:33:03,650 --> 00:33:05,690 Their speech is fluent, but it's 809 00:33:05,690 --> 00:33:09,100 amazingly empty of content. 810 00:33:09,100 --> 00:33:11,010 These patients have trouble producing speech, but their 811 00:33:11,010 --> 00:33:12,720 comprehension is decent. 812 00:33:12,720 --> 00:33:15,310 These patients produce speech pretty well, but their 813 00:33:15,310 --> 00:33:16,050 comprehension. 814 00:33:16,050 --> 00:33:20,320 So they're mirror opposites. 815 00:33:20,320 --> 00:33:21,400 And let's see, what do I want? 816 00:33:21,400 --> 00:33:21,970 Yes. 817 00:33:21,970 --> 00:33:26,620 So in this field, a frequently, incredibly 818 00:33:26,620 --> 00:33:29,240 frequently used picture to study aphasia is 819 00:33:29,240 --> 00:33:30,710 this specific picture. 820 00:33:30,710 --> 00:33:32,610 It's called the cookie theft picture. 821 00:33:32,610 --> 00:33:35,660 Why it's become widely used, I'm not exactly sure. 822 00:33:35,660 --> 00:33:38,920 But once it's widely used, then often everybody uses it. 823 00:33:38,920 --> 00:33:41,620 So they'll put a picture like this in front of an 824 00:33:41,620 --> 00:33:43,940 individual, and they'll ask them to describe 825 00:33:43,940 --> 00:33:44,530 what's going on. 826 00:33:44,530 --> 00:33:46,710 It's to elicit production. 827 00:33:46,710 --> 00:33:50,275 And you would say something like, there's two kids. 828 00:33:50,275 --> 00:33:51,860 The kid's on a stool. 829 00:33:51,860 --> 00:33:53,020 Uh oh, is he going to fall over? 830 00:33:53,020 --> 00:33:54,830 Because they're falling off the cookie jar, and the 831 00:33:54,830 --> 00:33:56,280 mother's sort of not paying attention. 832 00:33:56,280 --> 00:33:58,370 Her mind must be somewhere else because she's letting the 833 00:33:58,370 --> 00:34:00,310 water splish splash here, right? 834 00:34:00,310 --> 00:34:02,810 You would say something like that. 835 00:34:02,810 --> 00:34:05,150 So let's see what patients with aphasia say, and other 836 00:34:05,150 --> 00:34:06,960 examples of their difficulty with language. 837 00:34:16,400 --> 00:34:17,674 Yeah? 838 00:34:17,674 --> 00:34:20,290 AUDIENCE: [INAUDIBLE]. 839 00:34:20,290 --> 00:34:23,100 PROFESSOR: Their writing tends to go pretty much with their 840 00:34:23,100 --> 00:34:24,840 spoken language. 841 00:34:24,840 --> 00:34:27,310 That's a really good question about-- so the question is, 842 00:34:27,310 --> 00:34:28,699 what would their writing be like? 843 00:34:28,699 --> 00:34:33,952 It very much parallels their spoken language. 844 00:34:33,952 --> 00:34:34,430 Yeah? 845 00:34:34,430 --> 00:34:37,256 AUDIENCE: [INAUDIBLE]. 846 00:34:37,256 --> 00:34:38,130 PROFESSOR: Sorry? 847 00:34:38,130 --> 00:34:38,990 AUDIENCE: [INAUDIBLE] 848 00:34:38,990 --> 00:34:40,280 sign language? 849 00:34:40,280 --> 00:34:42,830 PROFESSOR: OK, so very good question. 850 00:34:42,830 --> 00:34:46,030 Could not fluent aphasics learn sign language to bypass, 851 00:34:46,030 --> 00:34:47,780 in a sense, their problem, right? 852 00:34:47,780 --> 00:34:50,020 So I'm about to answer that in a moment, 853 00:34:50,020 --> 00:34:51,360 right on the next slide. 854 00:34:51,360 --> 00:34:54,710 Not directly that, but the implication of that. 855 00:34:54,710 --> 00:34:56,610 Because the important thing is-- so let me show you this 856 00:34:56,610 --> 00:34:57,220 thing, and let me come back. 857 00:34:57,220 --> 00:34:59,650 The question is, could you train an aphasic to use sign 858 00:34:59,650 --> 00:35:02,700 language to get around his or her language problem, if it's 859 00:35:02,700 --> 00:35:03,770 a speech problem? 860 00:35:03,770 --> 00:35:10,180 So people have studied sign language as a language for 861 00:35:10,180 --> 00:35:12,870 many reasons, but a huge one is this. 862 00:35:12,870 --> 00:35:15,560 Because I'm going to interpret your question the way I need 863 00:35:15,560 --> 00:35:18,000 to, and then you can tell me if I did it right from your 864 00:35:18,000 --> 00:35:18,310 perspective. 865 00:35:18,310 --> 00:35:23,530 Which is, in what sense does language equal speech? 866 00:35:23,530 --> 00:35:27,010 Could you communicate linguistically like, but just 867 00:35:27,010 --> 00:35:30,300 switch to your hands, if for some reason-- and the answer 868 00:35:30,300 --> 00:35:33,290 is, that at the level of the problem of these patients, 869 00:35:33,290 --> 00:35:34,880 they could not do it. 870 00:35:34,880 --> 00:35:37,800 Because these kinds of patients, the problem isn't 871 00:35:37,800 --> 00:35:38,810 really speech. 872 00:35:38,810 --> 00:35:41,600 There are people who have problems with the motor 873 00:35:41,600 --> 00:35:42,730 apparatus to move their mouth. 874 00:35:42,730 --> 00:35:44,900 That does exist. 875 00:35:44,900 --> 00:35:48,040 Their problem is in language processes that produce your 876 00:35:48,040 --> 00:35:53,200 speech intent, or language processes that extract meaning 877 00:35:53,200 --> 00:35:54,310 from sounds. 878 00:35:54,310 --> 00:35:57,260 And those language processes that produce what you want to 879 00:35:57,260 --> 00:36:01,440 say, that comprehend what you hear or read, those are the 880 00:36:01,440 --> 00:36:04,420 same ones that are utilized, as far as we understand, 881 00:36:04,420 --> 00:36:06,870 whether you're producing language in the typical, vocal 882 00:36:06,870 --> 00:36:09,050 way, or in the less typical, but 883 00:36:09,050 --> 00:36:12,130 well-studied, way of sign language. 884 00:36:12,130 --> 00:36:12,530 Does that make sense? 885 00:36:12,530 --> 00:36:13,010 OK. 886 00:36:13,010 --> 00:36:14,170 So you can't get around it because 887 00:36:14,170 --> 00:36:16,440 it's a language problem. 888 00:36:16,440 --> 00:36:19,550 So both by brain imaging evidence, for example, here 889 00:36:19,550 --> 00:36:22,660 are patients who use sign language turning on Broca's 890 00:36:22,660 --> 00:36:25,490 area and Wernicke's area on tasks that are about 891 00:36:25,490 --> 00:36:26,575 comprehension and production. 892 00:36:26,575 --> 00:36:29,550 It's the same areas, whether it's using your hands for sign 893 00:36:29,550 --> 00:36:33,840 language or using your mouth to talk or your ear to hear. 894 00:36:33,840 --> 00:36:36,070 Further, there have been really fun studies where they 895 00:36:36,070 --> 00:36:39,960 took deaf infants and have shown-- and it's not easy to 896 00:36:39,960 --> 00:36:42,750 show, but I think most people are convinced that they babble 897 00:36:42,750 --> 00:36:43,370 with their hands. 898 00:36:43,370 --> 00:36:45,530 The same way babies make little sounds to get 899 00:36:45,530 --> 00:36:46,260 themselves going. 900 00:36:46,260 --> 00:36:48,720 We'll talk more about infants in a moment. 901 00:36:48,720 --> 00:36:51,030 Infants who grow up in an environment where they only 902 00:36:51,030 --> 00:36:55,430 learn sign language babble with their hands because 903 00:36:55,430 --> 00:36:58,880 speech, language is not about your mouth talking. 904 00:36:58,880 --> 00:37:02,420 It's about ideas that you can communicate by your production 905 00:37:02,420 --> 00:37:04,540 or comprehension, by your hand or by your mouth. 906 00:37:04,540 --> 00:37:08,860 So language is separable from speech, because even without 907 00:37:08,860 --> 00:37:12,010 speech, you communicate in very much the same way, in 908 00:37:12,010 --> 00:37:14,470 terms of sign language, by many studies. 909 00:37:14,470 --> 00:37:15,060 Yeah? 910 00:37:15,060 --> 00:37:19,326 AUDIENCE: So does that mean that people that [INAUDIBLE] 911 00:37:19,326 --> 00:37:22,650 imagined words or language? 912 00:37:22,650 --> 00:37:23,405 PROFESSOR: Say that again, sorry? 913 00:37:23,405 --> 00:37:25,283 AUDIENCE: Does that mean that they also couldn't imagine 914 00:37:25,283 --> 00:37:26,209 words or language? 915 00:37:26,209 --> 00:37:27,135 PROFESSOR: Who couldn't? 916 00:37:27,135 --> 00:37:29,510 AUDIENCE: People with Broca's area aphasia. 917 00:37:33,190 --> 00:37:35,010 PROFESSOR: I don't think so. 918 00:37:35,010 --> 00:37:36,720 We talked about this before, that-- 919 00:37:36,720 --> 00:37:39,820 I may not be understanding your question exactly, but-- 920 00:37:39,820 --> 00:37:42,890 in many ways, imagining something is the same part of 921 00:37:42,890 --> 00:37:43,890 the brain that does it. 922 00:37:43,890 --> 00:37:45,800 When we imagine a face, we turn on the parts of 923 00:37:45,800 --> 00:37:46,720 our brain that sees. 924 00:37:46,720 --> 00:37:49,300 I think when you imagine, if you-- 925 00:37:49,300 --> 00:37:50,300 I do this sometimes. 926 00:37:50,300 --> 00:37:51,510 I say, here's what I'm going to say to that 927 00:37:51,510 --> 00:37:53,220 person, in my head. 928 00:37:53,220 --> 00:37:54,770 And I practice that little speech. 929 00:37:54,770 --> 00:37:58,740 That's this part of the brain pretty much running. 930 00:37:58,740 --> 00:38:01,800 There's just a last little step of moving your mouth, but 931 00:38:01,800 --> 00:38:03,270 from the discussion we're having now, that's kind of a 932 00:38:03,270 --> 00:38:06,050 superficial thing of moving your mouth. 933 00:38:06,050 --> 00:38:09,170 That's not speech planning, speech thinking, speech 934 00:38:09,170 --> 00:38:10,110 intentions. 935 00:38:10,110 --> 00:38:14,130 Those are our core process for production, for comprehension, 936 00:38:14,130 --> 00:38:17,870 and I think imagined stuff is exactly the same way. 937 00:38:17,870 --> 00:38:18,650 Is that OK? 938 00:38:18,650 --> 00:38:19,100 Yeah. 939 00:38:19,100 --> 00:38:20,093 Yeah? 940 00:38:20,093 --> 00:38:22,804 AUDIENCE: So if they can't really imagine language, then 941 00:38:22,804 --> 00:38:25,516 how do they-- what is their thinking like? 942 00:38:25,516 --> 00:38:26,766 [INAUDIBLE]? 943 00:38:30,460 --> 00:38:35,030 PROFESSOR: Yeah, that's a good-- so the question is, if 944 00:38:35,030 --> 00:38:37,820 they have these troubles with core language ideas, 945 00:38:37,820 --> 00:38:39,870 abilities, what's their thinking like? 946 00:38:39,870 --> 00:38:43,660 I could just tell you, it's a classic debate for humans, how 947 00:38:43,660 --> 00:38:45,580 deeply language equals thought. 948 00:38:45,580 --> 00:38:48,420 But language [INAUDIBLE] in a sense of speech. 949 00:38:48,420 --> 00:38:50,790 It's just one of those things that people debate a lot 950 00:38:50,790 --> 00:38:53,000 because it depends what you mean by these things in many 951 00:38:53,000 --> 00:38:55,360 different ways. 952 00:38:55,360 --> 00:38:57,490 But if language means something like comprehending 953 00:38:57,490 --> 00:39:00,290 ideas in the world, it's hard to get around that for 954 00:39:00,290 --> 00:39:01,560 thinking [INAUDIBLE]. 955 00:39:01,560 --> 00:39:04,360 It means planning actions in the world that change the 956 00:39:04,360 --> 00:39:08,190 world around you, and communicating that, it's hard 957 00:39:08,190 --> 00:39:11,410 to not have that capacity for thinking in that way, right? 958 00:39:11,410 --> 00:39:14,900 So it's at this level, not whether you use your hands or 959 00:39:14,900 --> 00:39:17,990 your mouth, it's very hard to separate out what you might 960 00:39:17,990 --> 00:39:21,310 call thought and what you might call language. 961 00:39:21,310 --> 00:39:23,550 But keep in mind that these patients that we see, it's not 962 00:39:23,550 --> 00:39:26,040 like they lost all of language at all. 963 00:39:26,040 --> 00:39:28,100 So even the Broca's aphasic has trouble producing 964 00:39:28,100 --> 00:39:30,040 language, he's producing some, and he 965 00:39:30,040 --> 00:39:31,420 comprehends it pretty well. 966 00:39:31,420 --> 00:39:33,350 So it's not like these patients have lost all of 967 00:39:33,350 --> 00:39:35,840 their language circuitry, and therefore don't have thought 968 00:39:35,840 --> 00:39:36,820 available, right? 969 00:39:36,820 --> 00:39:39,260 They have a lot of language left in their head, and a lot 970 00:39:39,260 --> 00:39:40,460 of thought left in their mind. 971 00:39:40,460 --> 00:39:43,750 Is that OK? 972 00:39:43,750 --> 00:39:45,865 So one interesting thing that people have wondered, and 973 00:39:45,865 --> 00:39:47,770 where brain imaging gives us evidence that we couldn't have 974 00:39:47,770 --> 00:39:50,930 imagined 15 years ago, is this. 975 00:39:50,930 --> 00:39:53,180 So if you have damage, let's say, here's a patient with 976 00:39:53,180 --> 00:39:56,290 damage to the left frontal area. 977 00:39:56,290 --> 00:39:59,550 And they get better because they've had a stroke here or 978 00:39:59,550 --> 00:40:00,190 an injury here. 979 00:40:00,190 --> 00:40:01,170 They get better. 980 00:40:01,170 --> 00:40:02,850 A question that people have wondered is, do they get 981 00:40:02,850 --> 00:40:05,860 better by sort of somehow recovering ability in a part 982 00:40:05,860 --> 00:40:07,470 of their brain that got injured? 983 00:40:07,470 --> 00:40:10,120 Or do they get better because they use an entirely different 984 00:40:10,120 --> 00:40:11,820 pathway in their brain? 985 00:40:11,820 --> 00:40:13,340 Now, until brain imaging, you couldn't begin 986 00:40:13,340 --> 00:40:14,490 to touch that question. 987 00:40:14,490 --> 00:40:17,220 But now we have some evidence, and I'll make it just-- 988 00:40:17,220 --> 00:40:21,750 and so here's an example of a patient who has damage here. 989 00:40:21,750 --> 00:40:25,190 They have him do a task that in healthy people turns on 990 00:40:25,190 --> 00:40:28,330 exactly that place. 991 00:40:28,330 --> 00:40:30,780 And when he does it, he can do it OK. 992 00:40:30,780 --> 00:40:31,950 And where does he do it? 993 00:40:31,950 --> 00:40:33,630 In his right hemisphere. 994 00:40:33,630 --> 00:40:36,865 So this patient seems to switch which hemisphere he 995 00:40:36,865 --> 00:40:37,730 uses for language. 996 00:40:37,730 --> 00:40:40,650 It takes time and training to recover that. 997 00:40:40,650 --> 00:40:44,070 But it seems like he's found an alternate pathway to 998 00:40:44,070 --> 00:40:46,900 produce a language somehow. 999 00:40:46,900 --> 00:40:49,920 Turns out that the more people have studied these things, the 1000 00:40:49,920 --> 00:40:51,980 more complicated it gets. 1001 00:40:51,980 --> 00:40:54,260 Maybe just diversity of people, diversity of injuries, 1002 00:40:54,260 --> 00:40:55,140 or whatever. 1003 00:40:55,140 --> 00:40:57,030 So it doesn't always work this way. 1004 00:40:57,030 --> 00:40:59,350 But often, it seems like when people have better recovery 1005 00:40:59,350 --> 00:41:02,990 from a large injury to the speaking left hemisphere, they 1006 00:41:02,990 --> 00:41:06,480 find a way, somehow, through practice and training, to get 1007 00:41:06,480 --> 00:41:08,100 the right hemisphere to take over some of those 1008 00:41:08,100 --> 00:41:09,350 responsibilities. 1009 00:41:12,080 --> 00:41:13,010 Language acquisition. 1010 00:41:13,010 --> 00:41:15,920 So one of the most amazing things about infants is they 1011 00:41:15,920 --> 00:41:20,600 go from zero to speech in just a couple of years, and go 1012 00:41:20,600 --> 00:41:22,910 through an unbelievable training and program of 1013 00:41:22,910 --> 00:41:24,120 development. 1014 00:41:24,120 --> 00:41:25,410 So what happens? 1015 00:41:25,410 --> 00:41:28,060 In two or three months, they perceive all the phonemes. 1016 00:41:28,060 --> 00:41:30,130 They notice this change in phonemes. 1017 00:41:30,130 --> 00:41:32,510 By six months, they start to ignore distinctions among 1018 00:41:32,510 --> 00:41:34,130 sounds that are not used in their language. 1019 00:41:34,130 --> 00:41:36,680 In other words, other language sounds. 1020 00:41:36,680 --> 00:41:39,590 They start to babble, in some way getting their 1021 00:41:39,590 --> 00:41:41,050 speech ready to go. 1022 00:41:41,050 --> 00:41:43,520 By eight months, they start to identify single words in a 1023 00:41:43,520 --> 00:41:44,570 speech stream. 1024 00:41:44,570 --> 00:41:46,500 In a year, their babbling becomes 1025 00:41:46,500 --> 00:41:48,070 more adult-like sounding. 1026 00:41:48,070 --> 00:41:51,880 But a little bit after that, they get up to about 50 words 1027 00:41:51,880 --> 00:41:53,070 in understanding. 1028 00:41:53,070 --> 00:41:56,780 So comprehension always goes ahead of production. 1029 00:41:56,780 --> 00:41:58,920 Children understand words before they can speak them. 1030 00:41:58,920 --> 00:41:59,970 But they're lagging. 1031 00:41:59,970 --> 00:42:02,030 Here comes a speech, telegraphic speech, short 1032 00:42:02,030 --> 00:42:03,610 sentences at two years. 1033 00:42:03,610 --> 00:42:06,330 And then, finally, pretty complete speech, in 1034 00:42:06,330 --> 00:42:07,740 many ways, by nine. 1035 00:42:07,740 --> 00:42:12,570 So it's a long, long process, learning 10,000 words 1036 00:42:12,570 --> 00:42:14,010 estimated by the age of six. 1037 00:42:14,010 --> 00:42:16,470 That's a spectacular learning curve. 1038 00:42:16,470 --> 00:42:18,590 When they do experiments on infants where they measure 1039 00:42:18,590 --> 00:42:20,980 things like preference or learning by sucking rates on a 1040 00:42:20,980 --> 00:42:23,030 nipple because they can't talk, they try to figure out, 1041 00:42:23,030 --> 00:42:24,430 what is the infant hearing. 1042 00:42:24,430 --> 00:42:27,920 Within two hours of birth, they suck with more enthusiasm 1043 00:42:27,920 --> 00:42:30,200 to their mother's voice over another voice. 1044 00:42:30,200 --> 00:42:31,410 These are infants, this is their first 1045 00:42:31,410 --> 00:42:32,930 visit to their mother. 1046 00:42:32,930 --> 00:42:36,330 You have to sign up to do this experiment. 1047 00:42:36,330 --> 00:42:38,040 Now, they might have heard their mother's voice in a 1048 00:42:38,040 --> 00:42:44,200 certain way in the womb, right? 1049 00:42:44,200 --> 00:42:46,500 But they already have picked up, by three-day-old, they 1050 00:42:46,500 --> 00:42:49,050 prefer language to many other sounds, like music. 1051 00:42:49,050 --> 00:42:51,240 We come to love music, but that's not the urgent business 1052 00:42:51,240 --> 00:42:53,060 of the infant. 1053 00:42:53,060 --> 00:42:55,780 By four days old, they start to notice the differences 1054 00:42:55,780 --> 00:42:56,930 between languages. 1055 00:42:56,930 --> 00:42:59,180 This is amazing. 1056 00:42:59,180 --> 00:43:01,050 Their rate of learning is fantastic. 1057 00:43:01,050 --> 00:43:03,810 And by two months, they can tell the ba-ga distinction, 1058 00:43:03,810 --> 00:43:07,350 subtle distinctions, 40 milliseconds information. 1059 00:43:07,350 --> 00:43:09,970 And then they develop a continuingly strong preference 1060 00:43:09,970 --> 00:43:12,710 for the sounds of their native language. 1061 00:43:12,710 --> 00:43:15,760 Now, some years ago, people debated endlessly this left 1062 00:43:15,760 --> 00:43:17,800 hemisphere specialization for language. 1063 00:43:17,800 --> 00:43:19,320 This is fantastically essential 1064 00:43:19,320 --> 00:43:20,990 and striking in humans. 1065 00:43:20,990 --> 00:43:24,630 Does that grow over time, or is it in your mind 1066 00:43:24,630 --> 00:43:26,400 and brain at birth? 1067 00:43:26,400 --> 00:43:29,080 And the evidence is pretty compelling for many sources, 1068 00:43:29,080 --> 00:43:30,430 but here is maybe the most. 1069 00:43:30,430 --> 00:43:33,680 Here's fMRI on two-day-old infants. 1070 00:43:33,680 --> 00:43:36,630 You might ask, how do they instruct the infants to lie 1071 00:43:36,630 --> 00:43:39,110 still in the scanner and participate in the experiment? 1072 00:43:39,110 --> 00:43:43,110 And the answer is, at two days old, infants mostly just lay 1073 00:43:43,110 --> 00:43:44,410 there and don't do much. 1074 00:43:47,750 --> 00:43:48,390 They don't do much. 1075 00:43:48,390 --> 00:43:49,590 And there's a lot going on in their mind, but they don't 1076 00:43:49,590 --> 00:43:51,390 have much physical apparatus to do much. 1077 00:43:51,390 --> 00:43:54,870 So you could swaddle them very warmly, and just lay-- 1078 00:43:54,870 --> 00:43:57,050 you put them on a cradle into the fMRI scanner. 1079 00:43:57,050 --> 00:43:59,970 Their parents have signed up for them. 1080 00:43:59,970 --> 00:44:02,760 And you could play them sounds while they just lay there and 1081 00:44:02,760 --> 00:44:03,240 do nothing. 1082 00:44:03,240 --> 00:44:04,180 They can't push buttons. 1083 00:44:04,180 --> 00:44:04,980 They can't do stuff. 1084 00:44:04,980 --> 00:44:06,640 But you can see what's happening inside their brain. 1085 00:44:06,640 --> 00:44:09,520 And at two days old, here's the left hemisphere response 1086 00:44:09,520 --> 00:44:11,220 to language compared to the right. 1087 00:44:11,220 --> 00:44:14,870 So it's there instantly, we believe. 1088 00:44:14,870 --> 00:44:17,740 It's been there, actually in the womb as the child's been 1089 00:44:17,740 --> 00:44:18,600 developing. 1090 00:44:18,600 --> 00:44:21,470 This left hemisphere, genetically set up dominance 1091 00:44:21,470 --> 00:44:22,840 for language in almost everybody. 1092 00:44:26,810 --> 00:44:29,330 fMRI, just for those of you who-- 1093 00:44:29,330 --> 00:44:31,660 again, we can start doing it at about age five, but from 1094 00:44:31,660 --> 00:44:34,720 about three months to age five, it's incredibly hard to 1095 00:44:34,720 --> 00:44:36,530 do children in a scanner. 1096 00:44:36,530 --> 00:44:39,410 But the first couple days, it's not so hard. 1097 00:44:39,410 --> 00:44:41,730 Now, a really interesting line of research has 1098 00:44:41,730 --> 00:44:42,750 talked about motherese. 1099 00:44:42,750 --> 00:44:43,620 Have you heard this term? 1100 00:44:43,620 --> 00:44:46,210 So how do grown-ups, even college 1101 00:44:46,210 --> 00:44:47,720 students, talk to babies? 1102 00:44:47,720 --> 00:44:49,215 Do you talk to babies just like you talk 1103 00:44:49,215 --> 00:44:50,600 to everybody else? 1104 00:44:50,600 --> 00:44:51,850 No. 1105 00:44:53,790 --> 00:44:55,710 Cute baby. 1106 00:44:55,710 --> 00:44:56,960 Baby, baby. 1107 00:44:56,960 --> 00:44:58,210 And everybody looks like an idiot, right? 1108 00:45:00,740 --> 00:45:02,850 And you could just think, OK, that's just people being 1109 00:45:02,850 --> 00:45:03,900 idiots around babies. 1110 00:45:03,900 --> 00:45:06,690 But it turns out there's been beautiful, beautiful studies 1111 00:45:06,690 --> 00:45:10,290 to show that, while you spontaneously do this-- and 1112 00:45:10,290 --> 00:45:14,010 you and I don't take motherese or fatherese courses-- 1113 00:45:14,010 --> 00:45:18,070 but what we do spontaneously is that way of elongating 1114 00:45:18,070 --> 00:45:22,520 sounds, the intonations we give, are incredibly perfect 1115 00:45:22,520 --> 00:45:24,340 to help the baby learn language. 1116 00:45:24,340 --> 00:45:27,710 We're exactly doing what they can understand. 1117 00:45:27,710 --> 00:45:29,770 And that, again, must be virtually in 1118 00:45:29,770 --> 00:45:31,610 our genes, I think. 1119 00:45:31,610 --> 00:45:33,540 We hear it around, so it's not zero. 1120 00:45:33,540 --> 00:45:37,660 But the short pauses, careful enunciation, exaggerated 1121 00:45:37,660 --> 00:45:39,930 intonation, that's-- 1122 00:45:39,930 --> 00:45:41,880 you could do experiments where you take language and you get 1123 00:45:41,880 --> 00:45:43,380 rid of those, and the babies are like-- they don't know 1124 00:45:43,380 --> 00:45:43,860 what's going on. 1125 00:45:43,860 --> 00:45:44,770 They're not interested. 1126 00:45:44,770 --> 00:45:46,710 You put them back in, boom. 1127 00:45:46,710 --> 00:45:48,950 Those are perfect for the baby. 1128 00:45:48,950 --> 00:45:52,610 It's amazing, not only how babies are ready to go, but 1129 00:45:52,610 --> 00:45:55,090 how adults who talk with them are ready to go. 1130 00:45:55,090 --> 00:45:58,210 I mean, it's just amazing. 1131 00:45:58,210 --> 00:46:01,240 None of us will ever be as good a teacher in a classroom 1132 00:46:01,240 --> 00:46:03,690 as all of you will be with a baby anytime 1133 00:46:03,690 --> 00:46:04,490 you talk with them. 1134 00:46:04,490 --> 00:46:06,500 It's just amazing. 1135 00:46:06,500 --> 00:46:08,260 So there's beautiful experiments that show that 1136 00:46:08,260 --> 00:46:11,950 every time you tinker with the way the mother spontaneously, 1137 00:46:11,950 --> 00:46:14,930 or parents spontaneously, talk to indants, you make it worse, 1138 00:46:14,930 --> 00:46:16,750 less interesting, and less informative for the infant. 1139 00:46:19,400 --> 00:46:22,660 So now let's talk about a more formal experiment. 1140 00:46:22,660 --> 00:46:25,030 These are the classic experiment that nailed home 1141 00:46:25,030 --> 00:46:28,710 this message, that at birth we're universal understanders 1142 00:46:28,710 --> 00:46:30,260 of all sounds in the world. 1143 00:46:30,260 --> 00:46:33,800 And as the years go along, we became only good at the sounds 1144 00:46:33,800 --> 00:46:37,220 that are relevant, that are part of our own language. 1145 00:46:37,220 --> 00:46:41,380 A famous example in the US is a difficulty for Japanese 1146 00:46:41,380 --> 00:46:43,600 native speakers for the R-L distinction. 1147 00:46:43,600 --> 00:46:46,660 But every language has some distinctions it doesn't make, 1148 00:46:46,660 --> 00:46:48,660 and they're really hard when you get older. 1149 00:46:48,660 --> 00:46:49,780 So here's the idea. 1150 00:46:49,780 --> 00:46:53,450 In English, we make a distinction between ba and da, 1151 00:46:53,450 --> 00:46:55,800 and by 10 to 12 months, an infant can make that 1152 00:46:55,800 --> 00:46:56,660 distinction. 1153 00:46:56,660 --> 00:46:57,990 And certainly, adults can. 1154 00:46:57,990 --> 00:47:01,330 That's categorical perception that we talked about, that 1155 00:47:01,330 --> 00:47:04,990 kind of division between ba and da. 1156 00:47:04,990 --> 00:47:07,530 But there's sounds that occur in other language. 1157 00:47:07,530 --> 00:47:09,640 So we're shown here. 1158 00:47:09,640 --> 00:47:10,680 And you're going to hear-- 1159 00:47:10,680 --> 00:47:13,060 some of you may know Hindi sounds, and it'll be a 1160 00:47:13,060 --> 00:47:14,850 different experience for you. 1161 00:47:14,850 --> 00:47:17,760 Every year, when I first hear this clip I'm about to show 1162 00:47:17,760 --> 00:47:19,910 you, I think something's wrong. 1163 00:47:19,910 --> 00:47:21,640 Because they say, the infant's going to tell the difference 1164 00:47:21,640 --> 00:47:23,240 between da and da. 1165 00:47:23,240 --> 00:47:24,500 And I go, well, how are they going to do that? 1166 00:47:24,500 --> 00:47:25,880 I can't do that. 1167 00:47:25,880 --> 00:47:28,530 That's because they really are different sounds you're 1168 00:47:28,530 --> 00:47:31,570 hearing, but in English, they're not different sounds. 1169 00:47:31,570 --> 00:47:33,730 And so it all sounds the same to me. 1170 00:47:33,730 --> 00:47:35,540 I'm no longer a universal learner. 1171 00:47:35,540 --> 00:47:38,620 I haven't been since quite a while. 1172 00:47:38,620 --> 00:47:39,870 So here we go. 1173 00:47:43,750 --> 00:47:46,370 I'm stunned, always, by the brilliance of infant 1174 00:47:46,370 --> 00:47:50,080 researchers like this, who somehow, pretty convincingly 1175 00:47:50,080 --> 00:47:53,770 in most cases, really tell you what the infant knows or pays 1176 00:47:53,770 --> 00:47:56,103 attention to or thinks in pretty compelling ways, even 1177 00:47:56,103 --> 00:47:59,290 though they can't tell you themselves. 1178 00:47:59,290 --> 00:48:01,310 So one thing that's come up in the US-- 1179 00:48:01,310 --> 00:48:04,215 I mean, the whole world is becoming ever more bilingual 1180 00:48:04,215 --> 00:48:06,570 and trilingual. 1181 00:48:06,570 --> 00:48:08,473 There used to be some concerns, less now, and I'll 1182 00:48:08,473 --> 00:48:10,940 tell you, you don't have to worry about it. 1183 00:48:10,940 --> 00:48:13,200 Whether it's bad to learn two languages at once 1184 00:48:13,200 --> 00:48:13,870 when you're a kid. 1185 00:48:13,870 --> 00:48:16,016 And some parents worry about this, right? 1186 00:48:16,016 --> 00:48:17,510 You're going to be all messed up because you're going to 1187 00:48:17,510 --> 00:48:19,720 blend them all up and not do well in school. 1188 00:48:19,720 --> 00:48:22,345 And so there's been quite a bit of research, actually, 1189 00:48:22,345 --> 00:48:25,270 tracking and asking whether there's any downside. 1190 00:48:25,270 --> 00:48:26,590 I mean, there's huge upsides to knowing 1191 00:48:26,590 --> 00:48:27,860 two or three languages. 1192 00:48:27,860 --> 00:48:30,980 Are there any downsides in terms of language development? 1193 00:48:30,980 --> 00:48:35,540 And the objective evidence is pretty compelling that for 1194 00:48:35,540 --> 00:48:40,300 babbling, for first words, for pairs of words at a time, 1195 00:48:40,300 --> 00:48:42,680 [INAUDIBLE] at two months, that there's really no cost. 1196 00:48:42,680 --> 00:48:45,660 So they followed, in Canada, for example, children who grew 1197 00:48:45,660 --> 00:48:48,830 up learning English and French, English and ASL, 1198 00:48:48,830 --> 00:48:51,800 French or English only. 1199 00:48:51,800 --> 00:48:54,270 Everybody does the same, pretty much. 1200 00:48:54,270 --> 00:48:56,950 There's no cost, compared to the huge gain. 1201 00:48:56,950 --> 00:48:59,055 Sometimes some kids will get a little mixed up. 1202 00:48:59,055 --> 00:49:01,470 They'll actually mix up languages because they'll just 1203 00:49:01,470 --> 00:49:03,860 mix them up when they're pretty young. 1204 00:49:03,860 --> 00:49:06,560 But there's no developmental delay of milestones or 1205 00:49:06,560 --> 00:49:07,700 negative consequences. 1206 00:49:07,700 --> 00:49:10,920 There's only the benefit of having two or three languages 1207 00:49:10,920 --> 00:49:11,690 that you could speak. 1208 00:49:11,690 --> 00:49:13,430 So the evidence is overwhelming, empirically, 1209 00:49:13,430 --> 00:49:15,920 that there's no cost for learning more than one 1210 00:49:15,920 --> 00:49:19,790 language at a time when you're an infant. 1211 00:49:19,790 --> 00:49:23,070 One thing, there is a cost, a little bit, if you're a boy. 1212 00:49:23,070 --> 00:49:25,020 So unknown why this happened. 1213 00:49:25,020 --> 00:49:27,400 I don't think there's any deep science about it. 1214 00:49:27,400 --> 00:49:30,320 But everybody has observed that, for example, number of 1215 00:49:30,320 --> 00:49:32,560 new words understood during the first two years of life, 1216 00:49:32,560 --> 00:49:35,100 that girls, on average, outperform boys in language 1217 00:49:35,100 --> 00:49:36,350 acquisition early on. 1218 00:49:36,350 --> 00:49:38,600 And then things get closer, pretty much. 1219 00:49:38,600 --> 00:49:40,500 But the rate of learning on girls on average 1220 00:49:40,500 --> 00:49:42,280 is faster than boys. 1221 00:49:42,280 --> 00:49:46,570 Nobody, I think, understands the specific basis of that. 1222 00:49:46,570 --> 00:49:48,970 So when people talk about critical periods in language 1223 00:49:48,970 --> 00:49:52,930 acquisition, and what are fragile or resilient aspects 1224 00:49:52,930 --> 00:49:53,530 of language. 1225 00:49:53,530 --> 00:49:56,320 Which aspects of learning language that seem very 1226 00:49:56,320 --> 00:49:58,910 dependent on the age you are, and which are independent. 1227 00:49:58,910 --> 00:50:02,380 So phonology, including the production of language sounds, 1228 00:50:02,380 --> 00:50:03,490 seems very fragile. 1229 00:50:03,490 --> 00:50:05,510 Easy when you're young, harder when you're older. 1230 00:50:05,510 --> 00:50:07,990 Grammar is also age-sensitive, making subtle grammatical 1231 00:50:07,990 --> 00:50:10,080 distinctions. 1232 00:50:10,080 --> 00:50:13,180 Learning about meaning or vocabulary, you're perfectly 1233 00:50:13,180 --> 00:50:14,140 fine when you're an adult. 1234 00:50:14,140 --> 00:50:15,800 That doesn't seem to show something 1235 00:50:15,800 --> 00:50:17,290 like a sensitive period. 1236 00:50:17,290 --> 00:50:19,390 And here's one famous study that established 1237 00:50:19,390 --> 00:50:19,980 some of these things. 1238 00:50:19,980 --> 00:50:23,850 They looked at what age people arrive to different countries, 1239 00:50:23,850 --> 00:50:25,260 from different countries to the US and 1240 00:50:25,260 --> 00:50:26,300 started learning English. 1241 00:50:26,300 --> 00:50:29,650 These are people that didn't know English before. 1242 00:50:29,650 --> 00:50:33,440 They're all adults now, and they had them do quickly 1243 00:50:33,440 --> 00:50:35,120 grammatical judgments. 1244 00:50:35,120 --> 00:50:37,860 And what they found is, if you came to the US when you-- 1245 00:50:37,860 --> 00:50:40,560 if you were born in the US, or you came to the age three to 1246 00:50:40,560 --> 00:50:43,650 seven, you were very good at doing this. 1247 00:50:43,650 --> 00:50:47,590 But the later you came here, 8 to 10 years of age, 11 to 15, 1248 00:50:47,590 --> 00:50:52,270 17 to 39, your ability to make these fast, subtle grammatical 1249 00:50:52,270 --> 00:50:54,320 judgments just went down. 1250 00:50:54,320 --> 00:50:56,165 Even though you've been here, in many cases, for many years. 1251 00:50:56,165 --> 00:50:57,450 You're very smart. 1252 00:50:57,450 --> 00:50:58,770 Accents are like that, right? 1253 00:50:58,770 --> 00:51:00,990 People come to the US at a certain point in their 1254 00:51:00,990 --> 00:51:01,960 development. 1255 00:51:01,960 --> 00:51:03,580 They're very skilled in English, have a big 1256 00:51:03,580 --> 00:51:06,170 vocabulary, but the accent never disappears. 1257 00:51:06,170 --> 00:51:08,800 That's another thing in terms of language production that 1258 00:51:08,800 --> 00:51:12,250 has its fragile developmental early period. 1259 00:51:12,250 --> 00:51:13,810 So the last thing I'll do, and then show you a movie for 1260 00:51:13,810 --> 00:51:17,530 about eight minutes. 1261 00:51:17,530 --> 00:51:20,190 We get this occasional horrible experiments. 1262 00:51:20,190 --> 00:51:21,650 It's not even an experiment of nature. 1263 00:51:21,650 --> 00:51:25,120 It's just an experiment of horrible human behavior. 1264 00:51:25,120 --> 00:51:27,385 And the most famous one in language development, which 1265 00:51:27,385 --> 00:51:28,660 had a huge impact on the field at the 1266 00:51:28,660 --> 00:51:30,600 time, is a child, Genie. 1267 00:51:30,600 --> 00:51:31,660 I'll show you. 1268 00:51:31,660 --> 00:51:33,090 You'll see her in a movie clip in a moment. 1269 00:51:33,090 --> 00:51:37,800 They discovered her locked in a room, in a house, from age 1270 00:51:37,800 --> 00:51:39,510 20 months, approximately, until they 1271 00:51:39,510 --> 00:51:42,506 discovered her at 13. 1272 00:51:42,506 --> 00:51:44,640 She almost spoke to no one. 1273 00:51:44,640 --> 00:51:47,160 So the people taking care of her locked her in a closet, 1274 00:51:47,160 --> 00:51:49,832 basically, and did not talk with her, or she had no 1275 00:51:49,832 --> 00:51:51,550 language interactions until she was 1276 00:51:51,550 --> 00:51:52,945 discovered and rescued. 1277 00:51:52,945 --> 00:51:55,865 And then they performed research for years saying 1278 00:51:55,865 --> 00:51:58,280 could she learn things, what could she not learn. 1279 00:51:58,280 --> 00:52:01,030 She got single words, for example, but she never got 1280 00:52:01,030 --> 00:52:02,190 particularly good at grammar. 1281 00:52:02,190 --> 00:52:02,740 [INAUDIBLE] 1282 00:52:02,740 --> 00:52:03,490 syntax. 1283 00:52:03,490 --> 00:52:07,630 So a brutal way to test the idea that what's acquirable 1284 00:52:07,630 --> 00:52:08,780 later in life. 1285 00:52:08,780 --> 00:52:11,330 And what, if you don't learn it early in life, is 1286 00:52:11,330 --> 00:52:13,170 impossible to acquire fully? 1287 00:52:13,170 --> 00:52:13,980 So I'll end with this. 1288 00:52:13,980 --> 00:52:15,790 We'll do this for five minutes or seven minutes. 1289 00:52:18,810 --> 00:52:20,070 I'll stop there. 1290 00:52:20,070 --> 00:52:22,980 It's summarized in your book. 1291 00:52:22,980 --> 00:52:25,720 Everybody knows about it because it's this study you 1292 00:52:25,720 --> 00:52:28,535 couldn't do ethically in a million years. 1293 00:52:28,535 --> 00:52:30,840 You would never do, which is if you deprive a child of the 1294 00:52:30,840 --> 00:52:32,780 critical period of language exposure. 1295 00:52:32,780 --> 00:52:35,220 And she never got lots of aspects of language going. 1296 00:52:35,220 --> 00:52:38,070 She got OK on a minimal vocabulary, 1297 00:52:38,070 --> 00:52:38,910 grew in other ways. 1298 00:52:38,910 --> 00:52:41,235 But many of the things that, from a language perspective, 1299 00:52:41,235 --> 00:52:44,390 she never got because she missed that critical period. 1300 00:52:44,390 --> 00:52:47,000 So that's a bit of a sad story, obviously, but have a 1301 00:52:47,000 --> 00:52:48,815 good spring break and a refreshing spring break. 1302 00:52:48,815 --> 00:52:50,065 And I'll see you in 10 days.