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 00:00:28,020 --> 00:00:30,670 PROFESSOR: Last time, we talked about attention and the 9 00:00:30,670 --> 00:00:32,990 idea that attention has got some properties. 10 00:00:32,990 --> 00:00:35,270 We're very limited in what we can focus on. 11 00:00:35,270 --> 00:00:37,580 We attend to less than we might guess in our 12 00:00:37,580 --> 00:00:38,620 environment. 13 00:00:38,620 --> 00:00:40,730 On the other hand, there are channels of information that 14 00:00:40,730 --> 00:00:44,460 sneak into us unconsciously or with minimal attention. 15 00:00:44,460 --> 00:00:48,030 And experimental research has shown us what requires our 16 00:00:48,030 --> 00:00:51,290 focused attention to be noticed and what can sneak in 17 00:00:51,290 --> 00:00:55,290 through pathways, things like features in our environment. 18 00:00:55,290 --> 00:00:58,480 And so I want to talk to you today about two kinds of 19 00:00:58,480 --> 00:01:02,690 spectacular disorders of attention in a higher level 20 00:01:02,690 --> 00:01:05,390 vision and insight they give us into the 21 00:01:05,390 --> 00:01:06,600 brain basis of attention. 22 00:01:06,600 --> 00:01:10,720 And again, the message is how much we construct by the rules 23 00:01:10,720 --> 00:01:13,110 of our mind and brain the environment that 24 00:01:13,110 --> 00:01:14,940 we see around us. 25 00:01:14,940 --> 00:01:16,890 So we'll talk about blindsight. 26 00:01:16,890 --> 00:01:19,690 That's a great name, the paradoxical state that people 27 00:01:19,690 --> 00:01:23,580 are cortically blind, but they kind of perceive some things. 28 00:01:23,580 --> 00:01:25,430 So we'll talk about that. 29 00:01:25,430 --> 00:01:25,570 What is it? 30 00:01:25,570 --> 00:01:27,380 What do we know about its brain basis? 31 00:01:27,380 --> 00:01:29,430 What system of unconscious perception 32 00:01:29,430 --> 00:01:32,030 might be in our brains? 33 00:01:32,030 --> 00:01:35,300 In these patients, it's their only visual system. 34 00:01:35,300 --> 00:01:38,640 In you and I, it's something in us, and we don't know 35 00:01:38,640 --> 00:01:40,435 exactly what it's doing relative to our conscious 36 00:01:40,435 --> 00:01:41,420 visual system. 37 00:01:41,420 --> 00:01:44,100 But we have the same brain system available to us. 38 00:01:44,100 --> 00:01:46,780 And then neglect, what it is, its brain basis, and how it 39 00:01:46,780 --> 00:01:50,330 teaches us again how we construct the world around us 40 00:01:50,330 --> 00:01:52,960 to know what space we're in and what's around us. 41 00:01:55,570 --> 00:01:59,000 So a reminder, and I think you know this well by now that the 42 00:01:59,000 --> 00:02:01,830 world out there is divided into a left and right visual 43 00:02:01,830 --> 00:02:04,810 field as we look for it in the middle, that the information 44 00:02:04,810 --> 00:02:07,650 from the left visual field goes through your brain and 45 00:02:07,650 --> 00:02:10,539 ends up shown in the right primary visual cortex, from 46 00:02:10,539 --> 00:02:12,060 the right visual field into your left 47 00:02:12,060 --> 00:02:14,230 primary visual cortex. 48 00:02:14,230 --> 00:02:16,850 But there's one other pathway we haven't talked about very 49 00:02:16,850 --> 00:02:20,730 much which goes to a structure called the superior 50 00:02:20,730 --> 00:02:21,060 colliculus. 51 00:02:21,060 --> 00:02:23,450 It's part of your midbrain. 52 00:02:23,450 --> 00:02:26,510 And it's the system we think gives rise to the possibility 53 00:02:26,510 --> 00:02:28,090 of sensation without perception. 54 00:02:28,090 --> 00:02:30,230 That phrase, sensation without perception, is a good one to 55 00:02:30,230 --> 00:02:31,420 describe blindsight. 56 00:02:31,420 --> 00:02:33,070 And we'll describe it in a moment. 57 00:02:33,070 --> 00:02:37,080 So from your retina, where all vision has to go through, a 58 00:02:37,080 --> 00:02:38,750 little bit of information-- 59 00:02:38,750 --> 00:02:40,730 a small number of fibers-- go to part of your brain that 60 00:02:40,730 --> 00:02:43,450 controls your pupillary reflexes, what makes your 61 00:02:43,450 --> 00:02:47,270 pupils get wider or smaller to see. 62 00:02:47,270 --> 00:02:51,720 90% of the fibers coming in, the fibers come from your eye 63 00:02:51,720 --> 00:02:55,010 and go through the lateral geniculate or through the 64 00:02:55,010 --> 00:02:57,890 major system that you've heard about from Melissa that 65 00:02:57,890 --> 00:03:00,230 connect to your primary visual cortex. 66 00:03:00,230 --> 00:03:02,760 And then, there's one other small visual pathway from your 67 00:03:02,760 --> 00:03:05,520 retina to this superior colliculus sometimes called a 68 00:03:05,520 --> 00:03:06,760 tectopulvinar system. 69 00:03:06,760 --> 00:03:09,580 So it's a small pathway from your eyes in terms of the 70 00:03:09,580 --> 00:03:13,140 number of nerve fibers. 71 00:03:13,140 --> 00:03:15,350 And so people said, well, can we say what's not done by the 72 00:03:15,350 --> 00:03:20,090 major visual pathway that goes from the eye to the cortex? 73 00:03:20,090 --> 00:03:23,130 What's done by this other small pathway? 74 00:03:23,130 --> 00:03:25,090 And one of the ways they looked at it originally all 75 00:03:25,090 --> 00:03:28,710 the way back in 1881 was to create in dogs bilateral 76 00:03:28,710 --> 00:03:29,820 occipital lesions. 77 00:03:29,820 --> 00:03:30,900 So now, they're cortically blind. 78 00:03:30,900 --> 00:03:32,390 They're not retinally blind. 79 00:03:32,390 --> 00:03:33,220 They're cortically blind. 80 00:03:33,220 --> 00:03:34,540 It's in the cortex. 81 00:03:34,540 --> 00:03:35,670 And what could these animals do? 82 00:03:35,670 --> 00:03:36,540 And they were very impressed. 83 00:03:36,540 --> 00:03:39,140 Although these animals didn't recognize many things, they 84 00:03:39,140 --> 00:03:41,760 could steer their way around their environment. 85 00:03:41,760 --> 00:03:43,330 They wouldn't bump into things. 86 00:03:43,330 --> 00:03:47,360 If you had a blindfold on or if you were retinally blind 87 00:03:47,360 --> 00:03:49,250 and weren't given any opportunity to know your 88 00:03:49,250 --> 00:03:51,870 environment, you would bump into things, right? 89 00:03:51,870 --> 00:03:54,530 But these animals seemed to steer their way around things 90 00:03:54,530 --> 00:03:56,510 pretty well. 91 00:03:56,510 --> 00:03:59,970 And they can do some other very simple tasks even though 92 00:03:59,970 --> 00:04:02,190 they ought to have been seeing nothing. 93 00:04:02,190 --> 00:04:04,640 So this is a suggestion in animals that there's something 94 00:04:04,640 --> 00:04:07,910 in the brains of primates that gives you some information 95 00:04:07,910 --> 00:04:11,570 that doesn't go through your conscious cortex. 96 00:04:11,570 --> 00:04:14,640 And then, a number of patient studies in patients with 97 00:04:14,640 --> 00:04:17,510 naturally occurring injuries have really shown us, given us 98 00:04:17,510 --> 00:04:20,230 a chance to experiment on them in a human and relate them to 99 00:04:20,230 --> 00:04:22,000 human experience. 100 00:04:22,000 --> 00:04:26,550 So here's a patient who had a large injury, a large bleed, 101 00:04:26,550 --> 00:04:28,410 in the right visual cortex. 102 00:04:28,410 --> 00:04:31,070 So because of this, this patient, this man was blind in 103 00:04:31,070 --> 00:04:32,550 the left visual field. 104 00:04:32,550 --> 00:04:33,860 This field was fine. 105 00:04:33,860 --> 00:04:35,580 This field was blind. 106 00:04:35,580 --> 00:04:38,770 Cortically blind. 107 00:04:38,770 --> 00:04:43,770 And the way that people figure out in what way are you blind, 108 00:04:43,770 --> 00:04:46,590 what parts of the world do you see and do you not see, is 109 00:04:46,590 --> 00:04:48,610 they'll put you in front of a computer monitor. 110 00:04:48,610 --> 00:04:51,350 And they'll turn on lights in various locations. 111 00:04:51,350 --> 00:04:54,760 And they'll create a map like this, which shows you where 112 00:04:54,760 --> 00:04:58,370 you respond when a light comes on and where you don't see it. 113 00:04:58,370 --> 00:05:00,440 So your job, basically you just look in the middle. 114 00:05:00,440 --> 00:05:02,520 And you say, push a button when a light comes on. 115 00:05:02,520 --> 00:05:03,080 So you're waiting. 116 00:05:03,080 --> 00:05:06,530 And a light comes on somewhere on the monitor. 117 00:05:06,530 --> 00:05:08,610 So what this picture is showing you is that the person 118 00:05:08,610 --> 00:05:10,940 could respond when the lights came on anywhere on the left 119 00:05:10,940 --> 00:05:15,110 side, but never responded, never said a light came on on 120 00:05:15,110 --> 00:05:15,660 the right side. 121 00:05:15,660 --> 00:05:17,780 People call this perimetry. 122 00:05:17,780 --> 00:05:21,070 It's a standard neurological test of visual difficulty. 123 00:05:21,070 --> 00:05:24,400 Here's a person whose injury harms only a quadrant of their 124 00:05:24,400 --> 00:05:24,970 visual field. 125 00:05:24,970 --> 00:05:28,410 So they never respond when a light turns on in that quarter 126 00:05:28,410 --> 00:05:30,090 of the world out there. 127 00:05:30,090 --> 00:05:31,840 But the other three quarters, they respond to. 128 00:05:31,840 --> 00:05:33,500 So that's a way of testing what do you do. 129 00:05:33,500 --> 00:05:35,470 And you're not asking them anything sophisticated, just 130 00:05:35,470 --> 00:05:36,060 did a light come on. 131 00:05:36,060 --> 00:05:36,980 Is that OK? 132 00:05:36,980 --> 00:05:39,480 So for this patient, here's the mapping. 133 00:05:39,480 --> 00:05:41,650 This patient was fine in the right visual field. 134 00:05:41,650 --> 00:05:42,540 This is one eye. 135 00:05:42,540 --> 00:05:44,980 This is the other eye. 136 00:05:44,980 --> 00:05:46,230 And terrible-- 137 00:05:46,230 --> 00:05:48,990 with a few spots a little bit better-- because lesions 138 00:05:48,990 --> 00:05:52,120 occurring naturally in people are seldom perfect lesions. 139 00:05:52,120 --> 00:05:55,720 But you can see that all this area that's dark are areas 140 00:05:55,720 --> 00:05:58,260 that, when a light came on in the left visual field, this 141 00:05:58,260 --> 00:06:02,580 man never responded that anything had turned on. 142 00:06:02,580 --> 00:06:04,140 There's nothing simpler, right, than a light 143 00:06:04,140 --> 00:06:05,600 turning on and off. 144 00:06:05,600 --> 00:06:09,110 He did not experience anything turning on in that way in the 145 00:06:09,110 --> 00:06:12,170 left half of the world. 146 00:06:12,170 --> 00:06:18,512 So they noticed as they gave this test that even though he 147 00:06:18,512 --> 00:06:21,490 was saying, I don't see anything, nothing's happening, 148 00:06:21,490 --> 00:06:24,690 that when they flash something in that cortically blind 149 00:06:24,690 --> 00:06:28,290 field, he would move his eyes in that direction as if 150 00:06:28,290 --> 00:06:30,290 something in his mind and brain felt 151 00:06:30,290 --> 00:06:31,075 something had happened. 152 00:06:31,075 --> 00:06:34,340 Not only something happened, but roughly where it happened. 153 00:06:34,340 --> 00:06:36,480 But that information was not available to 154 00:06:36,480 --> 00:06:37,250 his conscious mind. 155 00:06:37,250 --> 00:06:39,280 He's never pushing a button that he says he saw it. 156 00:06:39,280 --> 00:06:40,380 He always says nothing. 157 00:06:40,380 --> 00:06:41,740 I'm waiting for something to come on. 158 00:06:41,740 --> 00:06:43,960 And if it comes on in his good field, he responds. 159 00:06:43,960 --> 00:06:45,020 Does that make sense, OK? 160 00:06:45,020 --> 00:06:46,860 But something seemed to do it. 161 00:06:46,860 --> 00:06:48,920 And when they found that it was better than chance in the 162 00:06:48,920 --> 00:06:51,510 left visual field, about things like if they put on a 163 00:06:51,510 --> 00:06:53,240 bigger patch of light. 164 00:06:53,240 --> 00:06:55,650 He could tell if they gave him a short line or a long line. 165 00:06:55,650 --> 00:06:59,300 Now, he would never say, I see the line. 166 00:06:59,300 --> 00:07:02,670 You would have to make him make a guess. 167 00:07:02,670 --> 00:07:05,100 So when you read the papers, it's something like, I don't 168 00:07:05,100 --> 00:07:05,550 see anything. 169 00:07:05,550 --> 00:07:06,210 I don't see anything. 170 00:07:06,210 --> 00:07:07,370 Well, you must guess. 171 00:07:07,370 --> 00:07:08,540 Is it a short line or a long line? 172 00:07:08,540 --> 00:07:09,410 I don't see it. 173 00:07:09,410 --> 00:07:10,660 There's no basis for me to guess. 174 00:07:10,660 --> 00:07:12,220 It'll be a completely random guess. 175 00:07:12,220 --> 00:07:13,810 But you must guess, OK? 176 00:07:13,810 --> 00:07:15,190 Short or long? 177 00:07:15,190 --> 00:07:17,980 And then, if the lines are far enough apart in size, he's 178 00:07:17,980 --> 00:07:18,806 almost 100%-- 179 00:07:18,806 --> 00:07:20,690 97% accurate. 180 00:07:20,690 --> 00:07:24,070 If he's forced to guess but he never has the experience that 181 00:07:24,070 --> 00:07:26,650 he sees the line, he's just forced to guess and told that 182 00:07:26,650 --> 00:07:27,700 it's two lines. 183 00:07:27,700 --> 00:07:31,210 Or he can judge things like, is it a circle or a cross? 184 00:07:31,210 --> 00:07:32,800 Is it an x or an o? 185 00:07:32,800 --> 00:07:35,060 But he can't do something like a square versus a rectangle. 186 00:07:35,060 --> 00:07:36,630 It's very limited. 187 00:07:36,630 --> 00:07:38,710 Subjectively, he always feels he sees nothing. 188 00:07:38,710 --> 00:07:42,780 If he's given two choices, for some things he can make the 189 00:07:42,780 --> 00:07:46,800 correct choice if he's forced to make a guess. 190 00:07:46,800 --> 00:07:49,170 And there's other sophisticated ways, again, to 191 00:07:49,170 --> 00:07:52,210 show that even though he's unconscious of anything in his 192 00:07:52,210 --> 00:07:56,210 blind field, something in his mind and brain is processing 193 00:07:56,210 --> 00:07:57,410 information there. 194 00:07:57,410 --> 00:07:59,710 So here, they had a thing where he pushed a button when 195 00:07:59,710 --> 00:08:01,010 a light came on. 196 00:08:01,010 --> 00:08:02,500 This is his good field. 197 00:08:02,500 --> 00:08:07,050 And it takes him, on average, 359 milliseconds. 198 00:08:07,050 --> 00:08:08,080 Now, they do the same thing. 199 00:08:08,080 --> 00:08:09,250 This is his good field. 200 00:08:09,250 --> 00:08:11,690 But they put on at the same time a light 201 00:08:11,690 --> 00:08:13,320 in his blind field. 202 00:08:13,320 --> 00:08:16,620 And when they do that, his time goes up by about a tenth 203 00:08:16,620 --> 00:08:20,440 of a second as if the distraction in the blind field 204 00:08:20,440 --> 00:08:23,130 was slightly distracting him from making that button press. 205 00:08:23,130 --> 00:08:26,370 So another objective way of demonstrating that some 206 00:08:26,370 --> 00:08:29,780 information has been processed in the blind field even though 207 00:08:29,780 --> 00:08:31,820 he never says he feels like something's happening there. 208 00:08:34,500 --> 00:08:37,419 So here's one more patient, and the last one I'll show you 209 00:08:37,419 --> 00:08:41,470 of this kind, who had the unfortunate occurrence of 210 00:08:41,470 --> 00:08:45,270 having two strokes, one in the left occipital cortex and one 211 00:08:45,270 --> 00:08:50,230 in the right occipital cortex, about 36 days apart. 212 00:08:50,230 --> 00:08:52,910 So now, he was blind in both fields by the time he had had 213 00:08:52,910 --> 00:08:53,820 both of his strokes. 214 00:08:53,820 --> 00:08:56,140 So he was a very unlucky person. 215 00:08:56,140 --> 00:08:59,140 Here in the dark is the missing cortex 216 00:08:59,140 --> 00:09:00,390 that has died away. 217 00:09:09,700 --> 00:09:13,580 Now, always the problems with humans is the injuries are not 218 00:09:13,580 --> 00:09:15,430 controlled and precise. 219 00:09:15,430 --> 00:09:19,550 And so here's two examples, one in monkeys, an incredibly 220 00:09:19,550 --> 00:09:23,110 clever experiment to get a monkey to tell you what he or 221 00:09:23,110 --> 00:09:25,380 she is thinking about. 222 00:09:25,380 --> 00:09:27,550 And then, one with infants as well, human infants. 223 00:09:27,550 --> 00:09:29,600 And how do you get a monkey to talk to you about their 224 00:09:29,600 --> 00:09:30,900 subjective experience? 225 00:09:30,900 --> 00:09:33,230 The striking thing about blindside is the person's 226 00:09:33,230 --> 00:09:34,110 saying, I see nothing. 227 00:09:34,110 --> 00:09:34,670 I see nothing. 228 00:09:34,670 --> 00:09:38,210 I see nothing, even as he walks past obstacles with 229 00:09:38,210 --> 00:09:40,600 precision and carefulness. 230 00:09:40,600 --> 00:09:43,025 So here, what it is, they took monkeys and made unilateral 231 00:09:43,025 --> 00:09:44,060 lesions in them. 232 00:09:44,060 --> 00:09:47,090 There's a control monkey and three where they surgically 233 00:09:47,090 --> 00:09:50,290 removed, as precisely as they could, the left occipital 234 00:09:50,290 --> 00:09:53,510 visual cortex and the corpus callosum that connects the 235 00:09:53,510 --> 00:09:55,050 left and the right. 236 00:09:55,050 --> 00:09:56,620 And the first task-- and I'll show you in a moment-- was to 237 00:09:56,620 --> 00:09:58,470 touch a light when it comes on. 238 00:09:58,470 --> 00:10:01,730 And the second half is the clever design to get the 239 00:10:01,730 --> 00:10:05,810 monkey to tell you what he or she subjectively 240 00:10:05,810 --> 00:10:08,550 feels is going on. 241 00:10:08,550 --> 00:10:11,370 So here's the video they would make of the monkey. 242 00:10:11,370 --> 00:10:13,790 And in one case, here's the light coming on. 243 00:10:13,790 --> 00:10:16,030 So the monkeys had left removal. 244 00:10:16,030 --> 00:10:19,140 So this is the blind side. 245 00:10:19,140 --> 00:10:22,310 These bars show you how often they point correctly to a 246 00:10:22,310 --> 00:10:23,520 light going on. 247 00:10:23,520 --> 00:10:27,060 And under this circumstance, forced to point, forced to 248 00:10:27,060 --> 00:10:29,850 point, here's the control animal. 249 00:10:29,850 --> 00:10:32,420 And you can see that the animals who are blind in this 250 00:10:32,420 --> 00:10:34,190 field do almost perfectly. 251 00:10:34,190 --> 00:10:37,950 When they're forced to point, they pick almost perfectly 252 00:10:37,950 --> 00:10:42,020 which stimulus comes on in the blind field. 253 00:10:42,020 --> 00:10:45,205 Now, they add one more thing to the experiment. 254 00:10:45,205 --> 00:10:49,380 They have a number of lights on the good side. 255 00:10:49,380 --> 00:10:53,370 Here is a response that they can push to signal "I saw 256 00:10:53,370 --> 00:10:56,540 nothing." And if they truly saw nothing, they get the 257 00:10:56,540 --> 00:11:00,250 juice reward for which they're working for. 258 00:11:00,250 --> 00:11:01,912 But there's a light that can come on here in their bad 259 00:11:01,912 --> 00:11:04,290 field on their right side. 260 00:11:04,290 --> 00:11:05,800 Now, what happens? 261 00:11:05,800 --> 00:11:08,570 Here's the control monkey doing perfectly well for the 262 00:11:08,570 --> 00:11:12,410 lights on this side, lights on this side, and when nothing is 263 00:11:12,410 --> 00:11:14,400 happening pushing this bar to signal 264 00:11:14,400 --> 00:11:15,450 that nothing is happening. 265 00:11:15,450 --> 00:11:16,570 Sometimes, no light comes on. 266 00:11:16,570 --> 00:11:19,330 So now, the monkeys will have to say, "I see nothing," by 267 00:11:19,330 --> 00:11:21,830 pushing this big panel up here if nothing seems 268 00:11:21,830 --> 00:11:23,230 to have turned on. 269 00:11:23,230 --> 00:11:26,660 But look what happens to the monkeys with the cortical 270 00:11:26,660 --> 00:11:28,230 lesions on the left. 271 00:11:28,230 --> 00:11:32,230 When this light comes on, they almost never say they saw it. 272 00:11:32,230 --> 00:11:35,070 They almost always push, "I saw nothing." 273 00:11:35,070 --> 00:11:39,240 When they're allowed to say "I saw nothing" by the response, 274 00:11:39,240 --> 00:11:41,590 then even though this thing that you know they can see-- 275 00:11:41,590 --> 00:11:43,330 because you see here they're responding 276 00:11:43,330 --> 00:11:45,630 perfectly well over here-- 277 00:11:45,630 --> 00:11:49,040 but when allowed to consciously respond what they 278 00:11:49,040 --> 00:11:52,240 see, then these black bars are all the way down. 279 00:11:52,240 --> 00:11:54,590 They almost never indicate they saw something. 280 00:11:54,590 --> 00:11:57,950 They almost always pick the response, "I saw nothing." So 281 00:11:57,950 --> 00:12:00,380 the monkey is telling you what his subjective experience is, 282 00:12:00,380 --> 00:12:02,870 which is like the humans with the cortical lesions. 283 00:12:02,870 --> 00:12:06,930 They're reporting they see nothing, even though some part 284 00:12:06,930 --> 00:12:09,750 of their brain can pick it up. 285 00:12:09,750 --> 00:12:10,640 How about in humans? 286 00:12:10,640 --> 00:12:14,550 So sometimes humans, children, infants, for medical reasons 287 00:12:14,550 --> 00:12:16,580 have to have hemispherectomies in the first year. 288 00:12:16,580 --> 00:12:20,050 These are unfortunate infants who have severe brain 289 00:12:20,050 --> 00:12:22,160 injuries, severe epilepsy. 290 00:12:22,160 --> 00:12:24,540 And it's considered better to help them by removing an 291 00:12:24,540 --> 00:12:27,670 entire hemisphere than to let them have the severity of the 292 00:12:27,670 --> 00:12:28,870 epilepsy they were having. 293 00:12:28,870 --> 00:12:32,820 These are rare cases in very unfortunate infants. 294 00:12:32,820 --> 00:12:34,950 And in these infants who got this for purely medical 295 00:12:34,950 --> 00:12:38,150 reasons to make their lives better, they also did an 296 00:12:38,150 --> 00:12:41,100 experiment to show you something not only about, I 297 00:12:41,100 --> 00:12:43,930 think, again, what happens in our conscious visual system, 298 00:12:43,930 --> 00:12:48,940 but also how that system grows in infancy and the growth of a 299 00:12:48,940 --> 00:12:50,780 conscious cortical visual system. 300 00:12:50,780 --> 00:12:53,510 So here's what they did. 301 00:12:53,510 --> 00:12:55,960 Infants this young-- because they're in their first year-- 302 00:12:55,960 --> 00:12:58,880 can't even point and you can't tell them to point. 303 00:12:58,880 --> 00:13:01,990 So again, you have to be clever experimentally. 304 00:13:01,990 --> 00:13:05,360 And what they did is they watched where their eyes moved 305 00:13:05,360 --> 00:13:06,600 and recorded that information. 306 00:13:06,600 --> 00:13:08,420 And that was the behavior. 307 00:13:08,420 --> 00:13:10,550 Sometimes, they would have a fixation. 308 00:13:10,550 --> 00:13:11,630 They've always had a fixation. 309 00:13:11,630 --> 00:13:12,870 You're looking in the middle. 310 00:13:12,870 --> 00:13:16,070 And then, something would come on out of side or this side, 311 00:13:16,070 --> 00:13:19,420 in the blind field or in the intact field. 312 00:13:22,190 --> 00:13:24,080 And they would see how often would their eyes move to a 313 00:13:24,080 --> 00:13:25,420 stimulus in their good field, which they 314 00:13:25,420 --> 00:13:26,550 expected all the time. 315 00:13:26,550 --> 00:13:28,560 But how often would it move to the stimulus in the blind 316 00:13:28,560 --> 00:13:30,280 field, the eye movement? 317 00:13:30,280 --> 00:13:34,180 Then, they had a competition condition where you have a dot 318 00:13:34,180 --> 00:13:35,010 in the middle. 319 00:13:35,010 --> 00:13:39,350 And that fixation dot would stay on while a box appeared 320 00:13:39,350 --> 00:13:40,720 here or here. 321 00:13:40,720 --> 00:13:41,500 So the only sense-- 322 00:13:41,500 --> 00:13:43,920 the only difference between these two is there's a dot in 323 00:13:43,920 --> 00:13:47,120 the middle that can compete for what you look at. 324 00:13:47,120 --> 00:13:47,420 OK? 325 00:13:47,420 --> 00:13:49,250 It's not a big competition. 326 00:13:49,250 --> 00:13:51,160 It's just a boring dot that stays on. 327 00:13:51,160 --> 00:13:52,950 But there's a big consequence. 328 00:13:52,950 --> 00:13:55,020 So here's how often they moved their eyes to the target in 329 00:13:55,020 --> 00:13:56,610 the non-competition condition. 330 00:13:56,610 --> 00:13:57,620 The dot goes on. 331 00:13:57,620 --> 00:13:58,400 It goes off. 332 00:13:58,400 --> 00:14:01,640 And the box comes on in your good field or your bad field. 333 00:14:01,640 --> 00:14:04,720 And all these bars are up at the top. 334 00:14:04,720 --> 00:14:07,795 And practically every trial, at eight weeks, 10 weeks, and 335 00:14:07,795 --> 00:14:11,540 12 weeks of age, the infant moves his or her eyes to the 336 00:14:11,540 --> 00:14:14,980 stimulus whether it's in the blind field or the good field. 337 00:14:14,980 --> 00:14:17,370 So something in their mind and brain is letting them identify 338 00:14:17,370 --> 00:14:20,150 something and moves their eyes to the good field, much like 339 00:14:20,150 --> 00:14:23,100 we talked about before for the adults. 340 00:14:23,100 --> 00:14:26,100 Now, in the competition condition, you can already see 341 00:14:26,100 --> 00:14:27,060 it's not quite the same. 342 00:14:27,060 --> 00:14:30,130 If there's a dot on and the box comes on their blind 343 00:14:30,130 --> 00:14:33,050 field, they don't always make it to the box. 344 00:14:33,050 --> 00:14:37,540 That dot is capturing their conscious cortical attention 345 00:14:37,540 --> 00:14:40,810 and diminishing the likelihood they notice the box coming on 346 00:14:40,810 --> 00:14:42,240 in the blind field. 347 00:14:42,240 --> 00:14:44,810 And as the weeks pass from eight to 10 to 12, just a 348 00:14:44,810 --> 00:14:46,270 month of development, look what happens. 349 00:14:46,270 --> 00:14:51,530 This bar goes from a little lower, a lot lower, near zero. 350 00:14:51,530 --> 00:14:54,060 That is, from eight to 12 weeks, what it looks like is 351 00:14:54,060 --> 00:14:58,370 happening is that as the cortical system matures and 352 00:14:58,370 --> 00:15:04,420 the infant's consciousness is growing in some sense, now 353 00:15:04,420 --> 00:15:06,920 it's no longer tending to process the information in the 354 00:15:06,920 --> 00:15:09,470 blind field if there's competition. 355 00:15:09,470 --> 00:15:15,130 Because the growth of that consciousness in the cortex is 356 00:15:15,130 --> 00:15:19,730 suppressing the ability of the infant to communicate with 357 00:15:19,730 --> 00:15:22,480 unconscious systems or be guided by unconscious systems 358 00:15:22,480 --> 00:15:23,730 in the brain. 359 00:15:23,730 --> 00:15:26,370 So the cool thing is the implication of this, is all of 360 00:15:26,370 --> 00:15:30,740 us have this collicular system in us. 361 00:15:30,740 --> 00:15:32,480 It's a visual system that's been around 362 00:15:32,480 --> 00:15:35,600 long through evolution. 363 00:15:35,600 --> 00:15:39,495 All of us have this massive conscious geniculate, the one 364 00:15:39,495 --> 00:15:41,270 that goes into your cortex system. 365 00:15:41,270 --> 00:15:43,430 And that dominates this other system. 366 00:15:43,430 --> 00:15:46,100 And so we only see it revealed in these 367 00:15:46,100 --> 00:15:48,560 patients as guiding behavior. 368 00:15:48,560 --> 00:15:50,970 But who knows what it really does in us? 369 00:15:50,970 --> 00:15:52,760 Because it's quietly sitting there. 370 00:15:52,760 --> 00:15:55,460 We don't have conscious access to it. 371 00:15:55,460 --> 00:15:57,140 And who knows how much it's guiding our behavior? 372 00:15:57,140 --> 00:15:59,350 And it's very hard to figure that out. 373 00:15:59,350 --> 00:16:02,080 But it's definitely disappearing from our 374 00:16:02,080 --> 00:16:06,160 conscious life within the first couple months of our 375 00:16:06,160 --> 00:16:08,430 development. 376 00:16:08,430 --> 00:16:11,240 So now, I'm going to switch to the second major disorder 377 00:16:11,240 --> 00:16:16,010 we'll talk about, attention and neglect, and go through 378 00:16:16,010 --> 00:16:19,230 anosagnosia, a spectacular version of that disorder, 379 00:16:19,230 --> 00:16:21,100 something about how it's behaviorally measured, its 380 00:16:21,100 --> 00:16:24,170 brain basis, and then a few more analyses. 381 00:16:24,170 --> 00:16:26,570 But in the book, there's a very nice 382 00:16:26,570 --> 00:16:27,730 chapter about these patients. 383 00:16:27,730 --> 00:16:31,620 Now, patients with blindsight are extremely rare. 384 00:16:31,620 --> 00:16:35,800 You have to have exactly the right kind of injury to damage 385 00:16:35,800 --> 00:16:38,160 a lot of your occipital cortex. 386 00:16:38,160 --> 00:16:42,350 And those kinds of injuries rarely occur on that scale. 387 00:16:42,350 --> 00:16:45,100 Attention and neglect, what I'm about to describe to you, 388 00:16:45,100 --> 00:16:47,740 if any of you become physicians or work in hospital 389 00:16:47,740 --> 00:16:52,250 settings, you are guaranteed to see this a lot. 390 00:16:52,250 --> 00:16:56,780 A lot-- it's very, very common for patients who've had things 391 00:16:56,780 --> 00:16:59,380 like stroke or brain injuries of some kind or another. 392 00:16:59,380 --> 00:17:02,890 And a pretty typical example is from Oliver Sacks. 393 00:17:02,890 --> 00:17:05,630 Most of the Sacks cases are pretty rare, prosopagnosia, 394 00:17:05,630 --> 00:17:06,690 pretty rare. 395 00:17:06,690 --> 00:17:07,310 Neglect? 396 00:17:07,310 --> 00:17:08,950 Incredibly common in the hospital ward, 397 00:17:08,950 --> 00:17:10,400 in neurology service. 398 00:17:10,400 --> 00:17:12,455 So here, he talks about a woman, an intelligent woman in 399 00:17:12,455 --> 00:17:15,119 her 60s, massive stroke affecting deep or inner back 400 00:17:15,119 --> 00:17:17,380 portions of her right cerebral hemisphere, good 401 00:17:17,380 --> 00:17:18,740 intelligence and humor. 402 00:17:18,740 --> 00:17:21,010 And what happens to her when they bring her her dessert or 403 00:17:21,010 --> 00:17:24,700 coffee on her tray in the hospital? 404 00:17:24,700 --> 00:17:26,630 PROFESSOR: Yeah, she complains that she's not getting enough 405 00:17:26,630 --> 00:17:30,320 food because she's only eating food on the 406 00:17:30,320 --> 00:17:32,810 right half of her plate. 407 00:17:32,810 --> 00:17:35,680 The left half of the plate, it's as if it 408 00:17:35,680 --> 00:17:37,960 weren't present for her. 409 00:17:37,960 --> 00:17:40,540 When they say, "But Mrs. S., it is right there on the 410 00:17:40,540 --> 00:17:42,530 left," she seems not to understand what they say and 411 00:17:42,530 --> 00:17:43,580 does not look to the left. 412 00:17:43,580 --> 00:17:45,640 If her head is gently turned so the dessert comes into 413 00:17:45,640 --> 00:17:48,140 sight in the preserved right half of her field, she says, 414 00:17:48,140 --> 00:17:49,030 "Oh, there it is! 415 00:17:49,030 --> 00:17:50,720 It wasn't there before." 416 00:17:50,720 --> 00:17:52,130 You understand? 417 00:17:52,130 --> 00:17:54,450 It's as if the left half of the plate did not exist. 418 00:17:54,450 --> 00:17:57,740 And if they swivel her head and now that left half of her 419 00:17:57,740 --> 00:18:01,790 plate is in her right field, now she goes, oh my gosh! 420 00:18:01,790 --> 00:18:03,400 Who snuck that on my plate? 421 00:18:03,400 --> 00:18:05,170 Now I can finish my meal. 422 00:18:05,170 --> 00:18:06,090 And it's not just that. 423 00:18:06,090 --> 00:18:10,350 She also only puts on makeup on half her face looking in 424 00:18:10,350 --> 00:18:14,180 the mirror, which can lead to comical impressions. 425 00:18:14,180 --> 00:18:18,330 So she ignores the left half of her world. 426 00:18:18,330 --> 00:18:20,660 And it's not just that it isn't there. 427 00:18:20,660 --> 00:18:21,990 It's as if it couldn't be there. 428 00:18:21,990 --> 00:18:24,180 It's as if, what are you talking about there's a left 429 00:18:24,180 --> 00:18:25,090 half of something? 430 00:18:25,090 --> 00:18:26,540 I see everything. 431 00:18:26,540 --> 00:18:28,250 So we'll talk a little about this and understand more 432 00:18:28,250 --> 00:18:29,280 of it coming up. 433 00:18:29,280 --> 00:18:33,480 So neglect means a failure to respond or report to something 434 00:18:33,480 --> 00:18:35,540 that's opposite to the lesion-- contralateral means 435 00:18:35,540 --> 00:18:36,910 opposite to the lesion-- 436 00:18:36,910 --> 00:18:38,420 that can't be accounted for by simple things. 437 00:18:38,420 --> 00:18:41,010 These patients don't have primary visual problems. 438 00:18:41,010 --> 00:18:41,980 They understand language. 439 00:18:41,980 --> 00:18:43,180 They're paying attention. 440 00:18:43,180 --> 00:18:45,930 They're the ones who deny the left half of their body. 441 00:18:45,930 --> 00:18:47,900 They dress on one side. 442 00:18:47,900 --> 00:18:50,130 They eat from one side of the plate. 443 00:18:50,130 --> 00:18:52,100 And they also have something that I'll show you in a 444 00:18:52,100 --> 00:18:55,400 moment, the example because it comes back a couple times. 445 00:18:55,400 --> 00:18:57,360 And it sounds fancy, but it's simple. 446 00:18:57,360 --> 00:19:00,060 There's extinction to double simultaneous stimulation seen 447 00:19:00,060 --> 00:19:01,740 in the late stages. 448 00:19:01,740 --> 00:19:06,190 So here's what the neurologist does-- and you'll see at least 449 00:19:06,190 --> 00:19:08,590 one neurologist doing this in a film clip coming up-- and 450 00:19:08,590 --> 00:19:10,650 they do this all the time in the hospital. 451 00:19:10,650 --> 00:19:11,930 They'll wiggle their fingers. 452 00:19:11,930 --> 00:19:13,800 They'll try to get it in the middle of the patient. 453 00:19:13,800 --> 00:19:15,515 This isn't carefully controlled, but it's done on 454 00:19:15,515 --> 00:19:16,360 the bedside. 455 00:19:16,360 --> 00:19:17,570 They'll wiggle one side and say, do you 456 00:19:17,570 --> 00:19:18,580 see anything moving? 457 00:19:18,580 --> 00:19:21,690 Or the other side, and sometimes they wiggle both. 458 00:19:21,690 --> 00:19:24,570 And the typical response in neglect is already 459 00:19:24,570 --> 00:19:25,600 fascinating. 460 00:19:25,600 --> 00:19:29,920 So past the early stages of the disorder, they'll notice 461 00:19:29,920 --> 00:19:31,790 the thing on the left side. 462 00:19:31,790 --> 00:19:34,440 From their perspective, that's their neglected side. 463 00:19:34,440 --> 00:19:35,700 They'll notice it on the right side. 464 00:19:35,700 --> 00:19:36,650 That's their good side. 465 00:19:36,650 --> 00:19:38,420 They're noticing this finger wiggling. 466 00:19:38,420 --> 00:19:39,550 They're noticing that finger wiggling. 467 00:19:39,550 --> 00:19:43,800 But when the physician wiggles both fingers at the same time, 468 00:19:43,800 --> 00:19:46,490 then the patient will only notice the 469 00:19:46,490 --> 00:19:47,680 one on the good side. 470 00:19:47,680 --> 00:19:51,170 It's as if this is extinguished because this one 471 00:19:51,170 --> 00:19:52,850 grabs your attention. 472 00:19:52,850 --> 00:19:55,540 And you know they can see it by itself. 473 00:19:55,540 --> 00:19:59,070 So it's only when it's both sides that it's extinguished. 474 00:19:59,070 --> 00:19:59,950 And we'll come back to that. 475 00:19:59,950 --> 00:20:00,640 It's interesting. 476 00:20:00,640 --> 00:20:02,260 It's not that their mind can't see. 477 00:20:02,260 --> 00:20:04,585 But when there's competition in the two fields-- which 478 00:20:04,585 --> 00:20:05,980 reminds me a little bit of blindsight -- 479 00:20:05,980 --> 00:20:09,120 then their mind can't see it. 480 00:20:09,120 --> 00:20:15,930 So a strong, a fascinating and rarer piece of this, but again 481 00:20:15,930 --> 00:20:18,810 not very rare, is something called anosagnosia where they 482 00:20:18,810 --> 00:20:23,140 not only have the neglect that I just described, but they 483 00:20:23,140 --> 00:20:25,700 deny any problem at all. 484 00:20:25,700 --> 00:20:29,200 So typically, the patient has a big, right lesions, about 5% 485 00:20:29,200 --> 00:20:30,720 of neglect cases. 486 00:20:30,720 --> 00:20:34,460 And a very fascinating neuroscientist, you may have 487 00:20:34,460 --> 00:20:35,170 read some of his stuff. 488 00:20:35,170 --> 00:20:40,330 He's a very creative mind, Ramachandran at UCSD, did some 489 00:20:40,330 --> 00:20:43,110 semi-experiments with some of these patients. 490 00:20:43,110 --> 00:20:46,590 So these are patients with right sided lesions. 491 00:20:46,590 --> 00:20:49,220 It says they have weakness or non-use of their left hand. 492 00:20:49,220 --> 00:20:50,670 And so here's his dialogue with them. 493 00:20:50,670 --> 00:20:51,850 Can you use your right hand? 494 00:20:51,850 --> 00:20:53,260 And that patient's hand is fine. 495 00:20:53,260 --> 00:20:54,100 Yes. 496 00:20:54,100 --> 00:20:56,230 Can use your left hand? 497 00:20:56,230 --> 00:20:56,930 Yes. 498 00:20:56,930 --> 00:20:59,870 The patient can't use her left hand. 499 00:20:59,870 --> 00:21:01,900 Are your hands equally strong? 500 00:21:01,900 --> 00:21:02,940 Yes. 501 00:21:02,940 --> 00:21:05,360 Can you point to my nose with your right hand? 502 00:21:05,360 --> 00:21:05,860 And she does. 503 00:21:05,860 --> 00:21:07,200 Her right hand is fine. 504 00:21:07,200 --> 00:21:10,050 Can you point to my nose with your left hand? 505 00:21:10,050 --> 00:21:12,480 The paralyzed left hand-- it's the left hand because it's a 506 00:21:12,480 --> 00:21:13,870 right hemisphere stroke-- 507 00:21:13,870 --> 00:21:15,850 does not move at all. 508 00:21:15,850 --> 00:21:17,310 Are you pointing to my nose? 509 00:21:17,310 --> 00:21:18,010 Yes. 510 00:21:18,010 --> 00:21:19,950 Can clearly see it pointing? 511 00:21:19,950 --> 00:21:22,670 Yes, it's about two inches from your nose. 512 00:21:22,670 --> 00:21:23,350 Can you clap? 513 00:21:23,350 --> 00:21:24,270 Of course I can clap. 514 00:21:24,270 --> 00:21:25,925 And here's what she does. 515 00:21:25,925 --> 00:21:26,960 Are you clapping? 516 00:21:26,960 --> 00:21:28,520 Yes, I'm clapping. 517 00:21:28,520 --> 00:21:29,680 She can't move her left side. 518 00:21:29,680 --> 00:21:33,710 But in every way in this patient's reports, she seems 519 00:21:33,710 --> 00:21:37,680 to deny in a deep sense that there's any problem in her 520 00:21:37,680 --> 00:21:40,910 performance or any weakness of any kind. 521 00:21:40,910 --> 00:21:45,370 So he wanted to do a couple little experiments to show 522 00:21:45,370 --> 00:21:51,120 that it's not just that they're saying, but they'll 523 00:21:51,120 --> 00:21:51,820 follow all the way through. 524 00:21:51,820 --> 00:21:55,540 So imagine that you had injured your left 525 00:21:55,540 --> 00:21:56,900 arm, was in a cast. 526 00:21:56,900 --> 00:21:59,930 And somebody asked you, I'm going to give you two choices. 527 00:21:59,930 --> 00:22:02,480 I'm going to give you $5 to screw in a light bulb-- 528 00:22:02,480 --> 00:22:04,340 your left arm is in a cast now-- 529 00:22:04,340 --> 00:22:06,400 or $10 to tie your shoe laces. 530 00:22:06,400 --> 00:22:09,080 Which would you take? 531 00:22:09,080 --> 00:22:09,740 The light bulb, right? 532 00:22:09,740 --> 00:22:12,360 Because it's going to be hard to tie your shoe laces with 533 00:22:12,360 --> 00:22:13,770 one arm out of action. 534 00:22:13,770 --> 00:22:14,970 This person is the same way. 535 00:22:14,970 --> 00:22:15,730 She's had a stroke. 536 00:22:15,730 --> 00:22:17,160 Her left arm's not functioning. 537 00:22:17,160 --> 00:22:21,060 She should definitely take the light bulb. 538 00:22:21,060 --> 00:22:22,480 She takes the shoe laces. 539 00:22:22,480 --> 00:22:24,710 When the physician, Ramachandran, describes as she 540 00:22:24,710 --> 00:22:28,300 sits there with one hand trying to flop the laces 541 00:22:28,300 --> 00:22:32,320 together making no progress at all, he says finally he has to 542 00:22:32,320 --> 00:22:33,550 end the exercise. 543 00:22:33,550 --> 00:22:34,710 He can't take it anymore. 544 00:22:34,710 --> 00:22:37,380 She'll just keep going until-- 545 00:22:37,380 --> 00:22:41,815 So she just doesn't process that her left side of her 546 00:22:41,815 --> 00:22:42,970 body's not working. 547 00:22:42,970 --> 00:22:46,130 And then, he does another experiment more impressive. 548 00:22:46,130 --> 00:22:49,060 I can use one of these, I think. 549 00:22:49,060 --> 00:22:53,870 So imagine this was a tray of cocktail glasses full of 550 00:22:53,870 --> 00:22:55,670 water, let's say to the very brim. 551 00:22:55,670 --> 00:22:58,190 Imagine there's three here and three-- six things. 552 00:22:58,190 --> 00:22:59,410 You can see they're right at the top. 553 00:22:59,410 --> 00:23:01,350 And you're just hoping that the person bringing it to you 554 00:23:01,350 --> 00:23:02,770 doesn't spill it on you. 555 00:23:02,770 --> 00:23:07,320 And the person brings it over to you, actually filled with 556 00:23:07,320 --> 00:23:10,110 water and asks a patient to hold the tray. 557 00:23:10,110 --> 00:23:12,580 OK, can I pick on you for one second? 558 00:23:12,580 --> 00:23:13,830 Imagine you had only-- 559 00:23:16,290 --> 00:23:18,250 how would you hold the tray if one arm was 560 00:23:18,250 --> 00:23:19,912 unavailable for you? 561 00:23:19,912 --> 00:23:22,270 OK, I'm bringing this over. 562 00:23:22,270 --> 00:23:23,810 You have to watch, very exciting. 563 00:23:23,810 --> 00:23:24,640 There's water. 564 00:23:24,640 --> 00:23:26,760 Yes, OK. 565 00:23:26,760 --> 00:23:28,690 How would you had if two hands were available to you? 566 00:23:28,690 --> 00:23:29,300 OK, thank you. 567 00:23:29,300 --> 00:23:29,640 OK, right? 568 00:23:29,640 --> 00:23:31,660 That's easy for you to imagine how you would hold it. 569 00:23:31,660 --> 00:23:33,390 They walk over to the patient with all this stuff. 570 00:23:33,390 --> 00:23:34,030 They hand it to her. 571 00:23:34,030 --> 00:23:35,120 And what does the patient do? 572 00:23:35,120 --> 00:23:36,840 She puts out her right hand on the right side. 573 00:23:36,840 --> 00:23:38,590 And the whole thing falls over. 574 00:23:38,590 --> 00:23:41,760 They're trying to demonstrate it goes all the way through. 575 00:23:41,760 --> 00:23:44,200 This person really believes there's not a problem. 576 00:23:44,200 --> 00:23:46,610 And they can be doused in water for a moment-- and I'm 577 00:23:46,610 --> 00:23:48,220 sure dried appropriately-- 578 00:23:48,220 --> 00:23:53,030 and still deny there's any problem at all. 579 00:23:53,030 --> 00:23:55,100 Now, one thing they can do-- and this is a weird line of 580 00:23:55,100 --> 00:23:58,760 research, but there's a number of papers that show this. 581 00:23:58,760 --> 00:24:00,580 And I'm not recommending you do this at home because 582 00:24:00,580 --> 00:24:04,290 actually, it's worse than it sounds. 583 00:24:04,290 --> 00:24:06,750 They take a syringe with cold water, and they put it into 584 00:24:06,750 --> 00:24:08,510 the left ear, the image is here. 585 00:24:08,510 --> 00:24:09,650 The patient's eye starts to move. 586 00:24:09,650 --> 00:24:11,020 They get a nystagmus. 587 00:24:11,020 --> 00:24:13,370 And they ask them how they feel. 588 00:24:13,370 --> 00:24:16,790 And then she says, my ear is very cold. 589 00:24:16,790 --> 00:24:18,040 But other than that, I'm fine. 590 00:24:20,530 --> 00:24:22,070 But they've given her a little bit of a 591 00:24:22,070 --> 00:24:24,110 shock in the left ear. 592 00:24:24,110 --> 00:24:27,220 And now, he does the interesting experiment. 593 00:24:27,220 --> 00:24:28,700 Do you feel OK? 594 00:24:28,700 --> 00:24:29,940 She says her ear is cold. 595 00:24:29,940 --> 00:24:31,180 Can you use your hands? 596 00:24:31,180 --> 00:24:34,020 At this moment when they've done something in the left ear 597 00:24:34,020 --> 00:24:37,250 that wakes up the opposite right hemisphere. 598 00:24:37,250 --> 00:24:39,405 I can use my right arm, but not my left arm. 599 00:24:39,405 --> 00:24:41,310 I want to move it, but it doesn't move. 600 00:24:41,310 --> 00:24:43,370 This happens just in a moment from the cold 601 00:24:43,370 --> 00:24:44,660 syringe in her ear. 602 00:24:44,660 --> 00:24:46,690 Whose arm is this? holding up the paralyzed arm. 603 00:24:46,690 --> 00:24:47,900 It's mine, of course. 604 00:24:47,900 --> 00:24:48,730 Can you use it? 605 00:24:48,730 --> 00:24:51,330 No, it's paralyzed-- like, what kind of doctor do I have? 606 00:24:51,330 --> 00:24:53,330 It's paralyzed, of course. 607 00:24:53,330 --> 00:24:55,360 Now, here's something really fun in a 608 00:24:55,360 --> 00:24:57,290 Sherlock Holmesian sense. 609 00:24:57,290 --> 00:24:58,705 How long has your arm been paralyzed? 610 00:24:58,705 --> 00:25:00,030 Did it start just now? 611 00:25:00,030 --> 00:25:02,620 Because what he's asking is, does she have a memory 612 00:25:02,620 --> 00:25:05,810 somewhere in her mind of her entire experience, or does she 613 00:25:05,810 --> 00:25:07,040 say it just started right now? 614 00:25:07,040 --> 00:25:07,910 I don't know how this happened. 615 00:25:07,910 --> 00:25:08,680 It's just not working. 616 00:25:08,680 --> 00:25:10,350 And she says, it's been paralyzed for 617 00:25:10,350 --> 00:25:12,250 several days now. 618 00:25:12,250 --> 00:25:14,500 About 90 minutes later when they redo this, she's back to 619 00:25:14,500 --> 00:25:15,880 just how she was. 620 00:25:15,880 --> 00:25:19,100 So they can temporarily alleviate this by this 621 00:25:19,100 --> 00:25:21,130 irrigation to the ear. 622 00:25:21,130 --> 00:25:25,730 So this denial of the left half of your body, this denial 623 00:25:25,730 --> 00:25:28,240 that you have any disorder whatsoever is a 624 00:25:28,240 --> 00:25:29,280 very striking thing. 625 00:25:29,280 --> 00:25:31,140 In most patients, it clears up. 626 00:25:31,140 --> 00:25:33,080 You saw pictures of it from Melissa. 627 00:25:33,080 --> 00:25:35,600 You saw movies of patients with object disorders. 628 00:25:35,600 --> 00:25:36,800 Those don't clear up. 629 00:25:36,800 --> 00:25:38,580 Balint's syndrome, spatial disorders-- 630 00:25:38,580 --> 00:25:40,820 those don't clear up. 631 00:25:40,820 --> 00:25:43,280 Anosagnosia patients grow out of it. 632 00:25:43,280 --> 00:25:47,750 Somehow, their brains recover over time. 633 00:25:47,750 --> 00:25:50,500 But again, it shows you how much attention is 634 00:25:50,500 --> 00:25:51,370 constructed, right? 635 00:25:51,370 --> 00:25:53,210 Because they have the stuff to represent 636 00:25:53,210 --> 00:25:54,690 their arm, their disease. 637 00:25:54,690 --> 00:25:56,870 That's all in their mind and brain. 638 00:25:56,870 --> 00:25:58,940 But the state they're in because of the brain injury 639 00:25:58,940 --> 00:26:01,790 lets them not construct that reality. 640 00:26:01,790 --> 00:26:03,390 So now, I'm going to show you measures of neglect. 641 00:26:03,390 --> 00:26:05,100 This is in your list just for your notes, but sort of fun 642 00:26:05,100 --> 00:26:06,330 just to look at the examples. 643 00:26:06,330 --> 00:26:07,940 So here's a patient. 644 00:26:07,940 --> 00:26:09,910 With these patients, they typically have right sided 645 00:26:09,910 --> 00:26:12,430 lesions, so the neglect is to the left half of the world. 646 00:26:12,430 --> 00:26:15,610 And here's a patient going to the bathroom as if all you can 647 00:26:15,610 --> 00:26:19,600 do is make right turns instead of going this way, as if the 648 00:26:19,600 --> 00:26:22,430 world weren't there, to proceed on the left. 649 00:26:22,430 --> 00:26:24,240 Here's another test that happens 650 00:26:24,240 --> 00:26:26,020 every day in a hospital. 651 00:26:26,020 --> 00:26:28,270 The physician has drawn these lines and says, 652 00:26:28,270 --> 00:26:29,700 cross out the lines. 653 00:26:29,700 --> 00:26:30,680 It's not perfect. 654 00:26:30,680 --> 00:26:31,510 The patient does that one. 655 00:26:31,510 --> 00:26:33,500 But look, they cross out all these lines. 656 00:26:33,500 --> 00:26:36,530 And the left half ones are mostly left uncrossed. 657 00:26:36,530 --> 00:26:39,380 It's as if they weren't there. 658 00:26:39,380 --> 00:26:41,060 Here's what's called a cancellation test. 659 00:26:41,060 --> 00:26:42,010 There's lots of letters here. 660 00:26:42,010 --> 00:26:44,640 And their job is to cross out all the A's. 661 00:26:44,640 --> 00:26:46,200 Now, let me start with neglect. 662 00:26:46,200 --> 00:26:47,980 You see over here, this whole area? 663 00:26:47,980 --> 00:26:50,430 Nothing is circled or crossed out. 664 00:26:50,430 --> 00:26:52,760 And you could say, well, what would happen if instead of 665 00:26:52,760 --> 00:26:56,970 neglect, you were like one of those blindsight patients who 666 00:26:56,970 --> 00:26:59,740 had a big lesion in the cortex and you were 667 00:26:59,740 --> 00:27:01,460 blind on one side? 668 00:27:01,460 --> 00:27:02,750 What would you do there? 669 00:27:02,750 --> 00:27:04,660 Well, it's easy for those patients because what they do 670 00:27:04,660 --> 00:27:06,480 is they don't see part of the world. 671 00:27:06,480 --> 00:27:07,860 But what do they do? 672 00:27:07,860 --> 00:27:11,180 They turn their head, just like you would do. 673 00:27:11,180 --> 00:27:12,190 They turn their head. 674 00:27:12,190 --> 00:27:14,370 They don't see it, but they know they don't see it. 675 00:27:14,370 --> 00:27:15,870 And they turn their head. 676 00:27:15,870 --> 00:27:18,790 And a patient who's blind on one side, loss in the visual 677 00:27:18,790 --> 00:27:22,200 field, gets all the lines because all you have to do if 678 00:27:22,200 --> 00:27:26,050 you're blind on one side is turn your head. 679 00:27:26,050 --> 00:27:29,100 It's not that hard in a practical sense. 680 00:27:29,100 --> 00:27:32,110 But if you don't imagine the left half of the world exists, 681 00:27:32,110 --> 00:27:33,540 where would you turn your head to? 682 00:27:33,540 --> 00:27:35,620 And that's what these neglect patients do, don't imagine the 683 00:27:35,620 --> 00:27:37,640 left half of the world exists. 684 00:27:37,640 --> 00:27:40,270 So here's an example of a patient reading a text. 685 00:27:40,270 --> 00:27:41,690 They're handed this text. 686 00:27:41,690 --> 00:27:45,710 The slash lines here are where this patient seems to think 687 00:27:45,710 --> 00:27:48,790 the left side of the page stops. 688 00:27:48,790 --> 00:27:52,360 OK So they're overcoming everything they know about how 689 00:27:52,360 --> 00:27:54,600 a sentence should be and reading this passage. 690 00:27:54,600 --> 00:27:58,410 The patient says, "had to pass the windows whom good morning 691 00:27:58,410 --> 00:28:02,560 message for the ground his with all his and he bottle." 692 00:28:02,560 --> 00:28:03,940 Thank you very much. 693 00:28:03,940 --> 00:28:07,985 It's right in front of them, but the left half of the page 694 00:28:07,985 --> 00:28:12,110 is just not present for this person's mind. 695 00:28:12,110 --> 00:28:14,550 Here is a person copying a flower. 696 00:28:14,550 --> 00:28:17,170 A psychologist or a neurologist draws this flower 697 00:28:17,170 --> 00:28:19,890 or has a flower ready to go, a drawing, and says copy 698 00:28:19,890 --> 00:28:21,230 everything you see. 699 00:28:21,230 --> 00:28:23,790 And it's not always totally perfect exactly how it works. 700 00:28:23,790 --> 00:28:26,240 But you can see there's a lot of the left side of this 701 00:28:26,240 --> 00:28:27,810 flower missing-- 702 00:28:27,810 --> 00:28:30,390 right in front of them. 703 00:28:30,390 --> 00:28:31,690 Here's a very simple one, too. 704 00:28:31,690 --> 00:28:33,680 Copy everything you see here. 705 00:28:33,680 --> 00:28:35,930 And what they see is these three things up here. 706 00:28:35,930 --> 00:28:38,010 Their job's to copy everything down here. 707 00:28:38,010 --> 00:28:39,810 They have all the time they want. 708 00:28:39,810 --> 00:28:40,870 Left side is neglected. 709 00:28:40,870 --> 00:28:42,170 And all they copy is the triangle. 710 00:28:42,170 --> 00:28:43,470 That's all they draw. 711 00:28:43,470 --> 00:28:45,850 And the tester will always say, are you done? 712 00:28:45,850 --> 00:28:46,800 Are you sure you're done? 713 00:28:46,800 --> 00:28:47,730 The person says, I'm sure I'm done. 714 00:28:47,730 --> 00:28:50,580 Thank you very much. 715 00:28:50,580 --> 00:28:52,180 Sometimes, they do something remarkable. 716 00:28:52,180 --> 00:28:54,410 They're shown a scene like this. 717 00:28:54,410 --> 00:28:56,400 Here's four trees with a house in the middle. 718 00:28:56,400 --> 00:28:59,740 And you can see this patient starts over here. 719 00:28:59,740 --> 00:29:02,120 They say, oh, there's a tree over, draws this. 720 00:29:02,120 --> 00:29:03,280 There's a house over here. 721 00:29:03,280 --> 00:29:05,990 And they jump from location to location. 722 00:29:05,990 --> 00:29:08,230 Every time their attention lands, they draw the right 723 00:29:08,230 --> 00:29:10,060 half of it. 724 00:29:10,060 --> 00:29:11,910 It's always as if the left were missing. 725 00:29:11,910 --> 00:29:16,290 And again, this idea of how constructed this is. 726 00:29:16,290 --> 00:29:17,250 Here's two more examples. 727 00:29:17,250 --> 00:29:19,430 And the clock thing, we'll talk a fair bit about. 728 00:29:19,430 --> 00:29:20,670 Here's a patient writing to dictation. 729 00:29:20,670 --> 00:29:21,890 The first sentence, they sort of stay-- 730 00:29:21,890 --> 00:29:23,450 but now, it's as if they were running out 731 00:29:23,450 --> 00:29:25,110 of room on the page. 732 00:29:25,110 --> 00:29:26,580 It's like they're reading, but it's writing. 733 00:29:26,580 --> 00:29:28,680 The left half of the page doesn't exist. 734 00:29:28,680 --> 00:29:30,530 Clocks are used a lot in this land, because it's kind of 735 00:29:30,530 --> 00:29:31,010 impressive. 736 00:29:31,010 --> 00:29:32,470 And we'll come back in a couple different versions 737 00:29:32,470 --> 00:29:32,850 about this. 738 00:29:32,850 --> 00:29:33,970 But look at that. 739 00:29:33,970 --> 00:29:37,620 They were asked to draw the time on a clock. 740 00:29:37,620 --> 00:29:39,950 And it's as if they could draw the time on the right side, 741 00:29:39,950 --> 00:29:40,910 their good side. 742 00:29:40,910 --> 00:29:44,620 But it's as if the left half of the clock didn't exist. 743 00:29:44,620 --> 00:29:48,180 Here's another patient asked to draw the time. 744 00:29:48,180 --> 00:29:53,720 And you see almost what seems like a struggle in the 745 00:29:53,720 --> 00:29:54,320 patient, right? 746 00:29:54,320 --> 00:29:56,010 They start on the right side. 747 00:29:56,010 --> 00:29:57,640 And then here, they're running out of space. 748 00:29:57,640 --> 00:29:59,030 They've got to cram in that 10. 749 00:29:59,030 --> 00:30:01,190 Their mind knows it goes to 12, right? 750 00:30:01,190 --> 00:30:03,580 But there's no space to put it in. 751 00:30:03,580 --> 00:30:07,310 And so you put them, in a sense, in a sense of conflict. 752 00:30:07,310 --> 00:30:08,640 And that's the top version. 753 00:30:08,640 --> 00:30:11,680 The bottom, they were given numbers one at a time. 754 00:30:11,680 --> 00:30:14,370 They were given, it tells you here, 12 and 6. 755 00:30:14,370 --> 00:30:16,000 So they put those in the right spots. 756 00:30:16,000 --> 00:30:16,990 Here comes 11. 757 00:30:16,990 --> 00:30:20,360 Already, 11 is like, uh-oh, right? 758 00:30:20,360 --> 00:30:23,790 And then, they get 4, 9. 759 00:30:23,790 --> 00:30:25,210 9 is not going to make it. 760 00:30:25,210 --> 00:30:27,530 And 10, they know it has to come after-- you can see that 761 00:30:27,530 --> 00:30:30,990 they put them actually in a struggle between what they 762 00:30:30,990 --> 00:30:33,520 know, something about where the numbers ought to go, but 763 00:30:33,520 --> 00:30:37,130 the impossibility of the left half existing. 764 00:30:37,130 --> 00:30:38,630 Now, here's something-- and we'll come back to this in a 765 00:30:38,630 --> 00:30:39,960 few minutes-- 766 00:30:39,960 --> 00:30:42,770 what happens if you just give them a piece of paper and say, 767 00:30:42,770 --> 00:30:43,770 write down 1 o'clock. 768 00:30:43,770 --> 00:30:45,160 And then, you take that piece of paper away. 769 00:30:45,160 --> 00:30:45,910 Write down 2 o'clock. 770 00:30:45,910 --> 00:30:47,190 Take that piece of paper away. 771 00:30:47,190 --> 00:30:47,550 Then look-- 772 00:30:47,550 --> 00:30:51,210 6, 7, 8, 9, 10, those are not bad, right? 773 00:30:51,210 --> 00:30:54,770 If they just do one of them, the very same patient who had 774 00:30:54,770 --> 00:30:57,690 to crowd everything on the right is quite comfortable in 775 00:30:57,690 --> 00:31:00,160 putting down a pretty good 9, 10, and 11 if 776 00:31:00,160 --> 00:31:01,830 it's just one of them. 777 00:31:01,830 --> 00:31:05,040 We'll come back in a little bit to experiments that help 778 00:31:05,040 --> 00:31:07,990 understand what's going on this case because we don't 779 00:31:07,990 --> 00:31:11,010 only want a scientist to say, wow, this is 780 00:31:11,010 --> 00:31:12,460 unbelievable and amazing. 781 00:31:12,460 --> 00:31:14,810 We like to say something more about how the mind is doing 782 00:31:14,810 --> 00:31:17,600 this and what part of their brain is important. 783 00:31:17,600 --> 00:31:20,110 And kind of impressively, here's a patient with eyes 784 00:31:20,110 --> 00:31:22,080 open mostly crowding on the right. 785 00:31:22,080 --> 00:31:25,640 Got the 10 on the left, but doing a better job when their 786 00:31:25,640 --> 00:31:27,310 eyes are closed. 787 00:31:27,310 --> 00:31:28,610 They missed the dial altogether. 788 00:31:28,610 --> 00:31:29,880 Their eyes are closed. 789 00:31:29,880 --> 00:31:31,120 But they actually do it-- the same patient 790 00:31:31,120 --> 00:31:32,250 does a better job. 791 00:31:32,250 --> 00:31:35,300 OK, so how does that work? 792 00:31:35,300 --> 00:31:38,230 And one more thing to mention is that neglect occurs across 793 00:31:38,230 --> 00:31:38,790 modalities. 794 00:31:38,790 --> 00:31:40,840 That is, when these patients have neglect, I 795 00:31:40,840 --> 00:31:42,390 focused on the visual. 796 00:31:42,390 --> 00:31:45,710 But these patients also don't do very well if they're doing 797 00:31:45,710 --> 00:31:47,100 things like reaching for things. 798 00:31:47,100 --> 00:31:48,210 It's not just vision. 799 00:31:48,210 --> 00:31:51,690 It's pretty much everything in the left half of the world. 800 00:31:51,690 --> 00:31:54,400 And you can do these kinds of things which, again, show not 801 00:31:54,400 --> 00:31:57,090 only their neglect but the constructed psychological 802 00:31:57,090 --> 00:31:58,460 nature of the neglect. 803 00:31:58,460 --> 00:32:00,710 It varies in ways that are interesting. 804 00:32:00,710 --> 00:32:02,690 So they're given a line like this and say 805 00:32:02,690 --> 00:32:03,860 mark the exact middle. 806 00:32:03,860 --> 00:32:05,210 You would draw something here. 807 00:32:05,210 --> 00:32:07,240 They draw here because they're going to neglect 808 00:32:07,240 --> 00:32:08,660 that part of the line. 809 00:32:08,660 --> 00:32:12,300 Then, they say read the A. So they draw the person's 810 00:32:12,300 --> 00:32:14,796 attention to A. And now draw it, and they get better. 811 00:32:14,796 --> 00:32:17,370 Then, they're asked to mark the middle. 812 00:32:17,370 --> 00:32:18,420 Not too good. 813 00:32:18,420 --> 00:32:20,030 Mark the middle-- but you see the difference here. 814 00:32:20,030 --> 00:32:22,120 The A is present or the B is present. 815 00:32:22,120 --> 00:32:24,210 And if the B is present, it pulls them over here. 816 00:32:24,210 --> 00:32:26,510 If the A is present, it pulls their attention over here. 817 00:32:26,510 --> 00:32:28,770 They put their hand at the middle and say. 818 00:32:28,770 --> 00:32:29,940 Now, please mark the middle. 819 00:32:29,940 --> 00:32:31,600 Their hand goes over here for the middle. 820 00:32:31,600 --> 00:32:33,635 But if they start them all the way over here, their hand will 821 00:32:33,635 --> 00:32:35,300 only go this far. 822 00:32:35,300 --> 00:32:37,360 So as you see, all these different movements are 823 00:32:37,360 --> 00:32:40,340 telling you that the mind is interpreting what the 824 00:32:40,340 --> 00:32:41,570 world is out there. 825 00:32:41,570 --> 00:32:44,650 If you pull a little bit the person to the left, they'll 826 00:32:44,650 --> 00:32:48,930 notice a little bit more of the left. 827 00:32:48,930 --> 00:32:50,180 Where is the injury? 828 00:32:52,650 --> 00:32:56,220 So almost everywhere you read still in neurology books to 829 00:32:56,220 --> 00:32:58,980 this day that it's in the parietal cortex. 830 00:32:58,980 --> 00:33:01,630 But in the last few years, people have mostly come to 831 00:33:01,630 --> 00:33:04,760 this idea that the damage tends to be in 832 00:33:04,760 --> 00:33:06,450 the temporal lobe. 833 00:33:06,450 --> 00:33:08,720 And what happens when the temporal lobe is injured, it 834 00:33:08,720 --> 00:33:11,910 knocks of the balance of attention in the left and 835 00:33:11,910 --> 00:33:13,680 right parietal cortex. 836 00:33:13,680 --> 00:33:16,610 And there's something about the activity in the right 837 00:33:16,610 --> 00:33:18,250 parietal cortex goes way down. 838 00:33:18,250 --> 00:33:20,620 That's paying attention to the left half of the world. 839 00:33:20,620 --> 00:33:22,990 And as patients recover from this, the balance comes back. 840 00:33:22,990 --> 00:33:25,260 And that's actually been measured now by brain imaging. 841 00:33:25,260 --> 00:33:27,700 Their attention comes back clinically, and it does in 842 00:33:27,700 --> 00:33:29,260 most patients. 843 00:33:29,260 --> 00:33:31,980 Then, the balance between the two parietal cortices get 844 00:33:31,980 --> 00:33:32,680 reestablished. 845 00:33:32,680 --> 00:33:35,690 So even though people thought the site of damage was here, 846 00:33:35,690 --> 00:33:38,830 the interpretation's usually here in the temporal lobe. 847 00:33:38,830 --> 00:33:43,160 But the consequence of that is reduced activity in this part 848 00:33:43,160 --> 00:33:45,010 of the brain, even if it's not physically injured. 849 00:33:53,640 --> 00:33:55,240 The fantastic thing is-- 850 00:33:55,240 --> 00:33:57,200 think about this for a second-- in order to ignore 851 00:33:57,200 --> 00:34:01,030 the left half of the flower, the left half of a design, the 852 00:34:01,030 --> 00:34:04,230 left half of a page, the left half of a clock, what do you 853 00:34:04,230 --> 00:34:06,680 have to know? 854 00:34:06,680 --> 00:34:07,910 Where the left and right are. 855 00:34:07,910 --> 00:34:09,440 It's not as if his eyes were closed. 856 00:34:09,440 --> 00:34:11,120 If your eyes were closed, you wouldn't know where left and 857 00:34:11,120 --> 00:34:12,810 right are on a page, right? 858 00:34:12,810 --> 00:34:15,980 He has to represent in his mind what is left and right 859 00:34:15,980 --> 00:34:17,639 reasonably accurately. 860 00:34:17,639 --> 00:34:20,739 And then, he extinguishes awareness that anything in the 861 00:34:20,739 --> 00:34:21,940 left could exist. 862 00:34:21,940 --> 00:34:24,120 But part of his mind has to know what is left for that to 863 00:34:24,120 --> 00:34:24,780 work, right? 864 00:34:24,780 --> 00:34:27,219 Otherwise, the digits would be all over the piece of paper, 865 00:34:27,219 --> 00:34:28,555 not even on the paper. 866 00:34:28,555 --> 00:34:30,139 He centers on the paper. 867 00:34:30,139 --> 00:34:32,179 He centers on the circle. 868 00:34:32,179 --> 00:34:33,790 Centering means I know what's left. 869 00:34:33,790 --> 00:34:35,070 I know what's the center. 870 00:34:35,070 --> 00:34:37,610 And then boom, the left disappears as a place that 871 00:34:37,610 --> 00:34:39,060 could exist. 872 00:34:39,060 --> 00:34:42,179 So these are all tasks in front of you. 873 00:34:42,179 --> 00:34:45,449 There's been some incredibly Sherlock Holmes like clever 874 00:34:45,449 --> 00:34:50,900 experiments asking whether you also neglect your imagination. 875 00:34:50,900 --> 00:34:52,940 Not what's in front of you, but your imagination. 876 00:34:52,940 --> 00:34:54,469 So here's the way they did it. 877 00:34:54,469 --> 00:34:57,640 Have any of you been in Milan? 878 00:34:57,640 --> 00:35:00,310 There's a central cathedral in part of town. 879 00:35:00,310 --> 00:35:02,560 It's a big deal. 880 00:35:02,560 --> 00:35:04,090 So they took Milanese patients, people who lived in 881 00:35:04,090 --> 00:35:06,110 Milan their whole lives who had strokes in the right 882 00:35:06,110 --> 00:35:08,920 hemisphere who had neglect, and they asked them to imagine 883 00:35:08,920 --> 00:35:12,130 the Piazza del Duomo, the major church there, looking at 884 00:35:12,130 --> 00:35:15,980 it from one side of the square or from entering from the 885 00:35:15,980 --> 00:35:19,160 opposite side of the square. 886 00:35:19,160 --> 00:35:20,370 And I'll show you the other experiment. 887 00:35:20,370 --> 00:35:21,340 Here's the idea. 888 00:35:21,340 --> 00:35:24,050 They said imagine that you're entering the square this 889 00:35:24,050 --> 00:35:27,730 direction so that the church is behind you, or this 890 00:35:27,730 --> 00:35:29,490 direction so that the church is in front of you. 891 00:35:29,490 --> 00:35:31,560 So you're entering the square from one side or from the 892 00:35:31,560 --> 00:35:32,090 other side. 893 00:35:32,090 --> 00:35:34,700 Now, the square that you've been too many times, that you 894 00:35:34,700 --> 00:35:37,260 know very well, tell me everything that's in the 895 00:35:37,260 --> 00:35:40,640 square as you imagine entering from one side. 896 00:35:40,640 --> 00:35:42,040 And here's what the patient reports. 897 00:35:42,040 --> 00:35:45,150 They're imagining coming out facing the church. 898 00:35:45,150 --> 00:35:50,650 And they report these kinds of things from this side. 899 00:35:50,650 --> 00:35:52,990 If that's only on the right side, they're 900 00:35:52,990 --> 00:35:53,740 ignoring the thing. 901 00:35:53,740 --> 00:35:54,890 So they say there's a cafe. 902 00:35:54,890 --> 00:35:57,920 There's a bookstore or whatever else there is here. 903 00:35:57,920 --> 00:35:59,540 That's everything that's in the square. 904 00:35:59,540 --> 00:36:01,450 Everything that's in the square is shown in red? 905 00:36:01,450 --> 00:36:03,200 Everything that's in the square. 906 00:36:03,200 --> 00:36:04,540 They wait just moments. 907 00:36:04,540 --> 00:36:06,950 And they say, now imagine instead you were coming out 908 00:36:06,950 --> 00:36:09,520 from the church, opposite view of the square. 909 00:36:09,520 --> 00:36:11,950 Tell me everything that's in the square. 910 00:36:11,950 --> 00:36:13,240 And here's what they tell you. 911 00:36:13,240 --> 00:36:15,250 The items that are in blue-- and they don't tell you the 912 00:36:15,250 --> 00:36:17,580 items they just told you, the locations they've just told 913 00:36:17,580 --> 00:36:19,900 you circled in red. 914 00:36:19,900 --> 00:36:22,680 So they're sitting their imagining their square. 915 00:36:22,680 --> 00:36:26,190 And then, they will ignore everything on the left, 916 00:36:26,190 --> 00:36:28,050 whatever's their subject of left. 917 00:36:28,050 --> 00:36:30,140 And you know they know it because all they have to do is 918 00:36:30,140 --> 00:36:32,000 imagine they're on the opposite side of the square, 919 00:36:32,000 --> 00:36:33,370 and then they report. 920 00:36:33,370 --> 00:36:34,090 Does that make sense? 921 00:36:34,090 --> 00:36:38,450 They're ignoring the left half of what they imagine the 922 00:36:38,450 --> 00:36:41,860 square looks like when they've been to it many times. 923 00:36:41,860 --> 00:36:44,400 And here's another patient doing exactly the same thing. 924 00:36:44,400 --> 00:36:45,770 Imagine you're coming out of the church. 925 00:36:45,770 --> 00:36:46,700 What's in the square? 926 00:36:46,700 --> 00:36:48,760 Well, here's some specific places I know. 927 00:36:48,760 --> 00:36:49,240 That's it? 928 00:36:49,240 --> 00:36:50,450 That's it. 929 00:36:50,450 --> 00:36:51,620 Wait a minute. 930 00:36:51,620 --> 00:36:55,550 Imagine you come this way into the square facing the church. 931 00:36:55,550 --> 00:36:57,350 What's everything in the square? 932 00:36:57,350 --> 00:37:01,020 And they only report the things on this side. 933 00:37:01,020 --> 00:37:01,870 So they're ignoring-- yeah? 934 00:37:01,870 --> 00:37:07,230 AUDIENCE: Does the patient realize after a few seconds? 935 00:37:07,230 --> 00:37:08,260 PROFESSOR: No, they never do. 936 00:37:08,260 --> 00:37:09,510 It's an excellent question. 937 00:37:09,510 --> 00:37:12,530 They just answered a moment ago one side, right? 938 00:37:12,530 --> 00:37:15,230 Why don't they tell you, I just told you the stuff on the 939 00:37:15,230 --> 00:37:17,010 other side? 940 00:37:17,010 --> 00:37:20,100 Because it's as if it couldn't exist. 941 00:37:20,100 --> 00:37:21,930 It's a little bit analogous to the patient 942 00:37:21,930 --> 00:37:23,390 whose arm isn't moving. 943 00:37:23,390 --> 00:37:25,010 And you go, do you have any problem? 944 00:37:25,010 --> 00:37:26,690 And they go, no, I don't have any problem. 945 00:37:26,690 --> 00:37:29,020 It's as if there couldn't be a problem. 946 00:37:29,020 --> 00:37:30,630 What are you talking about, right? 947 00:37:30,630 --> 00:37:33,000 So it overcomes all their knowledge and all their 948 00:37:33,000 --> 00:37:35,120 intelligence. 949 00:37:35,120 --> 00:37:38,140 It's as if I forced you to guess in detail what's in the 950 00:37:38,140 --> 00:37:40,200 back of the room if something new was there. 951 00:37:40,200 --> 00:37:41,310 And you go, there's no way. 952 00:37:41,310 --> 00:37:41,860 I can't see. 953 00:37:41,860 --> 00:37:45,180 I have no eyes in the back of my head. 954 00:37:45,180 --> 00:37:46,030 It's sort of like that. 955 00:37:46,030 --> 00:37:48,120 It's as if the left half couldn't exist. 956 00:37:48,120 --> 00:37:50,590 The contradiction they could note-- 957 00:37:50,590 --> 00:37:52,430 just a moment ago I told you the other one-- they don't 958 00:37:52,430 --> 00:37:56,000 notice it because something about this neglect swallows up 959 00:37:56,000 --> 00:37:58,350 all of your judgment. 960 00:37:58,350 --> 00:38:01,110 It's beautifully phrased by some neurologist as, it's as 961 00:38:01,110 --> 00:38:03,840 if the left half could not exist. 962 00:38:03,840 --> 00:38:06,990 Whenever you're thinking left, it doesn't exist. 963 00:38:06,990 --> 00:38:10,650 And ironically, you have to think left for that to work. 964 00:38:10,650 --> 00:38:11,510 That's the amazing thing. 965 00:38:11,510 --> 00:38:13,410 You have to go, I'm in the middle. 966 00:38:13,410 --> 00:38:13,970 There's a left. 967 00:38:13,970 --> 00:38:14,520 There's a right. 968 00:38:14,520 --> 00:38:15,630 Now, the left doesn't exist. 969 00:38:15,630 --> 00:38:17,000 And it couldn't exist. 970 00:38:17,000 --> 00:38:21,320 And every hint I get that it does exist, like there's food 971 00:38:21,320 --> 00:38:24,995 on that side or the pages usually go all the way here 972 00:38:24,995 --> 00:38:28,110 and makes the sentences make sense, it all disappears on 973 00:38:28,110 --> 00:38:30,200 you because it couldn't possibly exist. 974 00:38:30,200 --> 00:38:32,700 And the neat thing about that is it's striking 975 00:38:32,700 --> 00:38:33,380 neurologically. 976 00:38:33,380 --> 00:38:35,810 But that means in our own heads as we go around, we're 977 00:38:35,810 --> 00:38:39,330 constructing the world this way, building up two separate 978 00:38:39,330 --> 00:38:42,230 sides of our brain that are gluing together a picture of 979 00:38:42,230 --> 00:38:43,560 the world around us. 980 00:38:43,560 --> 00:38:45,620 And these patients lose that glue on one 981 00:38:45,620 --> 00:38:46,370 side of their brain. 982 00:38:46,370 --> 00:38:48,410 Is that OK? 983 00:38:48,410 --> 00:38:49,160 Here's another version. 984 00:38:49,160 --> 00:38:51,800 It's less flashy, but it's the same idea. 985 00:38:51,800 --> 00:38:54,120 Now, neglect can't get small enough. 986 00:38:54,120 --> 00:38:56,650 If you make something very tiny, then you 987 00:38:56,650 --> 00:38:57,810 don't ignore the left. 988 00:38:57,810 --> 00:38:59,700 Once it gets tiny enough, you can't do it. 989 00:38:59,700 --> 00:39:00,690 So they took advantage of that. 990 00:39:00,690 --> 00:39:02,680 And they show cloud like stimulus of these. 991 00:39:02,680 --> 00:39:04,350 But they didn't show them like this. 992 00:39:04,350 --> 00:39:05,880 They only had a slit. 993 00:39:05,880 --> 00:39:10,090 So you only saw the cloud a bit at a time. 994 00:39:10,090 --> 00:39:12,650 And you see one cloud, and then you see another cloud. 995 00:39:12,650 --> 00:39:14,870 Perhaps you'd see this cloud go by, and you see 996 00:39:14,870 --> 00:39:15,720 this cloud go by. 997 00:39:15,720 --> 00:39:18,580 And your job was to say were they identical clouds or not? 998 00:39:18,580 --> 00:39:20,550 And if they were not identical, on which side do 999 00:39:20,550 --> 00:39:22,210 they differ? 1000 00:39:22,210 --> 00:39:26,340 So because of all your visual experiences through the slit-- 1001 00:39:26,340 --> 00:39:29,850 which is too small for neglect to happen-- 1002 00:39:29,850 --> 00:39:32,380 what you do is you create in your mind's eye what does that 1003 00:39:32,380 --> 00:39:35,720 whole cloud look like as it passed through the slit in 1004 00:39:35,720 --> 00:39:36,990 your mind's eye? 1005 00:39:36,990 --> 00:39:38,210 And then, you see another one. 1006 00:39:38,210 --> 00:39:39,690 And you put that up in your mind's eye. 1007 00:39:39,690 --> 00:39:41,410 And you compare these two things that are in your 1008 00:39:41,410 --> 00:39:43,510 imagination in your mind's eyes. 1009 00:39:43,510 --> 00:39:46,280 And what happens is if these two things differ on the left 1010 00:39:46,280 --> 00:39:51,830 side, the patients rarely can make that distinction. 1011 00:39:51,830 --> 00:39:53,260 It's not because they can't see it. 1012 00:39:53,260 --> 00:39:55,110 It's always in that narrow slit. 1013 00:39:55,110 --> 00:39:57,620 But once they put the pieces together, they put it up in 1014 00:39:57,620 --> 00:40:00,580 their mind, the left half disappears on them in their 1015 00:40:00,580 --> 00:40:03,420 mind's eyes. 1016 00:40:03,420 --> 00:40:09,060 So here's an experimental approach to think about what 1017 00:40:09,060 --> 00:40:11,660 might be going wrong in these patients. 1018 00:40:11,660 --> 00:40:15,250 So they used a very simple task, which is when a light 1019 00:40:15,250 --> 00:40:16,520 comes on, you push a button. 1020 00:40:16,520 --> 00:40:17,740 That's all the task is. 1021 00:40:17,740 --> 00:40:20,030 Any light comes on, you push a button. 1022 00:40:20,030 --> 00:40:21,440 And sometimes, they'll put an arrow. 1023 00:40:21,440 --> 00:40:23,700 And sometimes, you have no information. 1024 00:40:23,700 --> 00:40:25,740 The light comes on on the left or the right. 1025 00:40:25,740 --> 00:40:27,910 And sometimes, they'll put on an arrow in the middle that 1026 00:40:27,910 --> 00:40:31,445 will warn you whether the light is likely to come on in 1027 00:40:31,445 --> 00:40:33,230 the left or the right. 1028 00:40:33,230 --> 00:40:34,800 So sometimes, you have neutral things. 1029 00:40:34,800 --> 00:40:35,970 You get a cross in the middle. 1030 00:40:35,970 --> 00:40:37,220 Then, a light comes on. 1031 00:40:37,220 --> 00:40:38,030 You don't have to say left and right. 1032 00:40:38,030 --> 00:40:39,820 You just push a button when one of those goes on. 1033 00:40:39,820 --> 00:40:42,250 Sometimes, he gets an error that's called valid that, 80% 1034 00:40:42,250 --> 00:40:45,002 of the time if it's pointing this way, it will turn out on 1035 00:40:45,002 --> 00:40:47,150 that side, 80% it will turn on this side. 1036 00:40:47,150 --> 00:40:48,970 So 80% of the time, it's honest. 1037 00:40:48,970 --> 00:40:51,170 And 20% of the time, it's dishonest. 1038 00:40:51,170 --> 00:40:53,610 So here's what it looks like. 1039 00:40:53,610 --> 00:40:56,840 You're looking here at a computer display. 1040 00:40:56,840 --> 00:40:59,010 That thing disappears. 1041 00:40:59,010 --> 00:41:01,060 And then, either an x is here or here. 1042 00:41:01,060 --> 00:41:01,730 And you push a button. 1043 00:41:01,730 --> 00:41:02,320 That's all. 1044 00:41:02,320 --> 00:41:03,910 Or a light comes on, and you just push a button. 1045 00:41:03,910 --> 00:41:04,410 That's all. 1046 00:41:04,410 --> 00:41:07,420 If it came on on the left or the right, I push button. 1047 00:41:07,420 --> 00:41:10,600 When an arrow appears, 80% of the time it's warning you 1048 00:41:10,600 --> 00:41:13,130 where that light will appear. 1049 00:41:13,130 --> 00:41:18,600 20%, it's dishonest and it appears on the opposite side. 1050 00:41:18,600 --> 00:41:21,620 So you will know, how good an experimental psychologist you 1051 00:41:21,620 --> 00:41:24,610 are right now, if I ask you which condition do you think 1052 00:41:24,610 --> 00:41:28,110 you're the fastest to push the button, when you have an arrow 1053 00:41:28,110 --> 00:41:30,930 that's truly telling you where the light will come on, an 1054 00:41:30,930 --> 00:41:33,610 arrow that's misleading you, or an x 1055 00:41:33,610 --> 00:41:34,430 that tells you nothing? 1056 00:41:34,430 --> 00:41:37,430 Which do you think you'll be fastest? 1057 00:41:37,430 --> 00:41:38,450 PROFESSOR: Where the arrow's pointing, right? 1058 00:41:38,450 --> 00:41:40,290 Like, here's the answer, over here! 1059 00:41:40,290 --> 00:41:41,620 OK, thank you very much. 1060 00:41:41,620 --> 00:41:44,820 Which do you think you'll be slowest on? 1061 00:41:44,820 --> 00:41:46,390 The dishonest arrow, right? 1062 00:41:46,390 --> 00:41:48,510 The arrow says, look over here, look over here! 1063 00:41:48,510 --> 00:41:49,520 And you're looking over there. 1064 00:41:49,520 --> 00:41:50,130 And you go, oh no! 1065 00:41:50,130 --> 00:41:50,890 It came on the other side. 1066 00:41:50,890 --> 00:41:52,960 You lied to me! 1067 00:41:52,960 --> 00:41:53,790 And the x is the middle. 1068 00:41:53,790 --> 00:41:54,720 And here's the data. 1069 00:41:54,720 --> 00:41:56,740 And it's a very simple experiment, right? 1070 00:41:56,740 --> 00:41:57,610 How fast are you? 1071 00:41:57,610 --> 00:41:59,220 This is reaction time just to push a button 1072 00:41:59,220 --> 00:42:00,370 when it comes on. 1073 00:42:00,370 --> 00:42:03,010 Here's the neutral condition in the middle. 1074 00:42:03,010 --> 00:42:06,730 You're a little bit faster if it's an honest arrow. 1075 00:42:06,730 --> 00:42:07,930 You're a little bit slower if it's a 1076 00:42:07,930 --> 00:42:10,350 dishonest, misleading arrow. 1077 00:42:10,350 --> 00:42:13,920 So now, you do this exact experiment. 1078 00:42:13,920 --> 00:42:14,800 And I'll show you the data. 1079 00:42:14,800 --> 00:42:19,850 And then, I'll simplify it for you with patients who have 1080 00:42:19,850 --> 00:42:22,590 right sided damage, left sided neglect. 1081 00:42:22,590 --> 00:42:25,790 And you can see as you look at these lines that the arrow can 1082 00:42:25,790 --> 00:42:27,750 be honest or dishonest, and it can be on the 1083 00:42:27,750 --> 00:42:29,400 left or right side. 1084 00:42:29,400 --> 00:42:32,040 Now, if you were always bad on the neglected side, you go, 1085 00:42:32,040 --> 00:42:33,170 well, that's not a big surprise. 1086 00:42:33,170 --> 00:42:34,450 But here's a surprise. 1087 00:42:34,450 --> 00:42:36,550 Patients were only bad-- 1088 00:42:36,550 --> 00:42:40,950 the times were way up here only when they had a dishonest 1089 00:42:40,950 --> 00:42:43,970 arrow that sent them into their good side. 1090 00:42:43,970 --> 00:42:45,490 That's when they were really bad. 1091 00:42:45,490 --> 00:42:47,130 So let's take a look at this again. 1092 00:42:47,130 --> 00:42:48,780 So here's the bad side. 1093 00:42:48,780 --> 00:42:50,070 Here's the good side. 1094 00:42:50,070 --> 00:42:53,330 When that arrow comes on that's honest, good. 1095 00:42:53,330 --> 00:42:57,990 When an arrow comes on that's honest this way, they do fine. 1096 00:42:57,990 --> 00:42:59,400 That's their bad field, but they do fine. 1097 00:42:59,400 --> 00:43:01,810 Tiny bit slower, but just a tiny bit. 1098 00:43:01,810 --> 00:43:04,800 Arrow comes on that moves them into their bad field but 1099 00:43:04,800 --> 00:43:06,930 really the light is on here, they do fine. 1100 00:43:06,930 --> 00:43:10,970 But if an arrow sends them into their good field, then 1101 00:43:10,970 --> 00:43:14,295 they're really, really slow to get back here. 1102 00:43:14,295 --> 00:43:17,210 So Posner argued that when you move your attention in the 1103 00:43:17,210 --> 00:43:20,150 world, you have three steps you have to do. 1104 00:43:20,150 --> 00:43:22,270 You have to disengage your attention from where you're 1105 00:43:22,270 --> 00:43:23,710 paying attention, just logically. 1106 00:43:23,710 --> 00:43:25,340 I'm paying attention here right now. 1107 00:43:25,340 --> 00:43:26,420 I'm going to pay attention over here. 1108 00:43:26,420 --> 00:43:29,600 I have to pull myself up from here, move my attention over 1109 00:43:29,600 --> 00:43:31,540 here, and then focus here. 1110 00:43:31,540 --> 00:43:34,300 So you disengage, get out from where you are, move to where 1111 00:43:34,300 --> 00:43:35,920 you need to go, and land and then focus 1112 00:43:35,920 --> 00:43:37,300 what you want to do. 1113 00:43:37,300 --> 00:43:40,600 And the only condition where they're bad is where they have 1114 00:43:40,600 --> 00:43:43,680 to get their attention out of the good field as if once 1115 00:43:43,680 --> 00:43:46,460 they're in that good field, once their mind is landed in 1116 00:43:46,460 --> 00:43:48,660 that good field, they're in quicksand. 1117 00:43:48,660 --> 00:43:51,100 And it's going to be really hard to get their attention to 1118 00:43:51,100 --> 00:43:53,470 move into the bad field. 1119 00:43:53,470 --> 00:43:54,520 So think about this. 1120 00:43:54,520 --> 00:43:57,930 The clocks are perfect for this because when you draw a 1121 00:43:57,930 --> 00:43:59,390 clock mostly-- 1122 00:43:59,390 --> 00:44:00,900 think about that as intuitively-- 1123 00:44:00,900 --> 00:44:03,460 if I was to ask you to draw the numbers on a clock, you 1124 00:44:03,460 --> 00:44:05,320 start with a 12 typically. 1125 00:44:05,320 --> 00:44:08,070 Then, what's the next one you would draw? 1126 00:44:08,070 --> 00:44:11,180 One, because that's how we're taught to do clocks. 1127 00:44:11,180 --> 00:44:13,330 Disaster if you have neglect. 1128 00:44:13,330 --> 00:44:15,110 You're in the good field. 1129 00:44:15,110 --> 00:44:18,550 Now, the left half of the clock has disappeared on you 1130 00:44:18,550 --> 00:44:21,950 because the clock has made you land your attention on the 1131 00:44:21,950 --> 00:44:23,260 good field. 1132 00:44:23,260 --> 00:44:25,730 And now, you can't pull out of it. 1133 00:44:25,730 --> 00:44:29,350 But what happens if you only have to draw 8 o'clock? 1134 00:44:29,350 --> 00:44:31,930 Your attention never got moved into the good field. 1135 00:44:31,930 --> 00:44:34,200 It's just starting from middle, so to speak. 1136 00:44:34,200 --> 00:44:36,980 And this very same patient can draw the 8 o'clock or 10 1137 00:44:36,980 --> 00:44:38,220 o'clock pretty well. 1138 00:44:38,220 --> 00:44:39,710 Does that makes sense? 1139 00:44:39,710 --> 00:44:43,340 Because they never got stuck in the good field. 1140 00:44:43,340 --> 00:44:45,400 They only moved into the bad field. 1141 00:44:45,400 --> 00:44:47,340 They can move into the bad field. 1142 00:44:47,340 --> 00:44:51,040 And so if their eyes are closed, that's better. 1143 00:44:51,040 --> 00:44:52,260 They get less stuck. 1144 00:44:52,260 --> 00:44:53,630 And now, we understand this thing. 1145 00:44:53,630 --> 00:44:56,210 Why is it these patients, if both fingers are moving-- 1146 00:44:56,210 --> 00:44:58,230 because once their attention is drawn into the good field, 1147 00:44:58,230 --> 00:45:00,160 it's as if the bad field disappeared on them. 1148 00:45:00,160 --> 00:45:04,370 But if they only get stimulated in the bad field, 1149 00:45:04,370 --> 00:45:08,820 so right side here, then they're OK because they never 1150 00:45:08,820 --> 00:45:11,580 paid that much attention to the good field. 1151 00:45:11,580 --> 00:45:12,445 So this is a nice experiment. 1152 00:45:12,445 --> 00:45:14,240 It shows you what is the problem. 1153 00:45:14,240 --> 00:45:17,100 The problem is once you're paying attention to the good 1154 00:45:17,100 --> 00:45:20,730 field, the normal, healthy field, it's so powerful 1155 00:45:20,730 --> 00:45:22,500 compared to the weakened representation here, that you 1156 00:45:22,500 --> 00:45:24,440 never leave it because it just seems like everything. 1157 00:45:26,980 --> 00:45:29,420 Now, here's a clever one. 1158 00:45:29,420 --> 00:45:32,620 Again, this shows you how much of attention is created by our 1159 00:45:32,620 --> 00:45:36,570 minds as opposed to just simply defined by the 1160 00:45:36,570 --> 00:45:37,410 environment. 1161 00:45:37,410 --> 00:45:41,350 So what if you show a display to somebody with neglect and 1162 00:45:41,350 --> 00:45:45,850 then rotate the display right in front of them? 1163 00:45:45,850 --> 00:45:47,860 So initially, the neglect is going to be on the left side. 1164 00:45:47,860 --> 00:45:50,520 But imagine the thing is turning over like this, right 1165 00:45:50,520 --> 00:45:51,460 in front of them. 1166 00:45:51,460 --> 00:45:55,590 Will the neglect travel with the initial assignment? 1167 00:45:55,590 --> 00:45:57,790 So this is from Marlene Behrmann, a very clever 1168 00:45:57,790 --> 00:45:58,370 experiment. 1169 00:45:58,370 --> 00:45:59,530 They have to pay attention if the light 1170 00:45:59,530 --> 00:46:00,930 comes on here or here. 1171 00:46:00,930 --> 00:46:03,180 But what they do is while the experiment's going on, right 1172 00:46:03,180 --> 00:46:06,000 in front of you, it slowly rotates over to here. 1173 00:46:06,000 --> 00:46:08,300 And sure enough, then the light comes on. 1174 00:46:08,300 --> 00:46:13,180 Sure enough, the neglect now moves into the good field 1175 00:46:13,180 --> 00:46:15,509 because once you've assigned left and right, you 1176 00:46:15,509 --> 00:46:17,300 know this is left. 1177 00:46:17,300 --> 00:46:18,840 So OK, you turn it over. 1178 00:46:18,840 --> 00:46:21,340 That's still really left. 1179 00:46:21,340 --> 00:46:22,340 But think how weird that is. 1180 00:46:22,340 --> 00:46:23,790 The mind is deciding that. 1181 00:46:23,790 --> 00:46:26,720 In an absolute sense, this thing is on the right. 1182 00:46:26,720 --> 00:46:28,600 But the mind said, this is the leftward one. 1183 00:46:28,600 --> 00:46:31,780 And you can flip it over, but you're not tricking me. 1184 00:46:31,780 --> 00:46:33,940 I know it's on the left, and I'm considering it the 1185 00:46:33,940 --> 00:46:35,360 leftward one. 1186 00:46:35,360 --> 00:46:37,370 The mind is deciding what counts as left and 1187 00:46:37,370 --> 00:46:40,830 right, not the world. 1188 00:46:40,830 --> 00:46:44,370 And what other kinds of information is being processed 1189 00:46:44,370 --> 00:46:47,190 that's not reaching attention levels? 1190 00:46:47,190 --> 00:46:50,070 So here's a cute experiment. 1191 00:46:50,070 --> 00:46:53,930 They would say to these patients, any difference 1192 00:46:53,930 --> 00:46:55,200 between these two things? 1193 00:46:55,200 --> 00:46:56,940 No. 1194 00:46:56,940 --> 00:46:58,920 But if you had to live in one of these houses, which one do 1195 00:46:58,920 --> 00:46:59,580 you think you'd live? 1196 00:46:59,580 --> 00:47:00,170 Well, I don't know. 1197 00:47:00,170 --> 00:47:00,800 They're pretty much the same. 1198 00:47:00,800 --> 00:47:01,460 Why would I pick one? 1199 00:47:01,460 --> 00:47:02,810 Well, pick one! 1200 00:47:02,810 --> 00:47:04,900 They go, ah, this looks like a little better place to live if 1201 00:47:04,900 --> 00:47:06,280 I have to pick one. 1202 00:47:06,280 --> 00:47:07,690 Which vase do you want? 1203 00:47:07,690 --> 00:47:08,070 I don't know. 1204 00:47:08,070 --> 00:47:08,880 They look the same. 1205 00:47:08,880 --> 00:47:09,590 You have to pick. 1206 00:47:09,590 --> 00:47:11,350 I pick this one. 1207 00:47:11,350 --> 00:47:13,180 Which glass to drink from? 1208 00:47:13,180 --> 00:47:14,140 You have to pick. 1209 00:47:14,140 --> 00:47:14,430 Pick this one. 1210 00:47:14,430 --> 00:47:17,640 So they consciously are not aware of what's going on here 1211 00:47:17,640 --> 00:47:19,560 when there's information to the opposite side to draw 1212 00:47:19,560 --> 00:47:20,410 their attention. 1213 00:47:20,410 --> 00:47:22,570 But something in their mind somewhere is picking up 1214 00:47:22,570 --> 00:47:23,670 information. 1215 00:47:23,670 --> 00:47:25,870 So the last question-- and I'll show you a final video-- 1216 00:47:25,870 --> 00:47:26,690 is this. 1217 00:47:26,690 --> 00:47:29,450 What kind of information is picked up in the neglected 1218 00:47:29,450 --> 00:47:33,700 field as you decide, some part of your mind, to neglect it? 1219 00:47:33,700 --> 00:47:38,240 So imagine if I showed you two forks versus 1220 00:47:38,240 --> 00:47:39,490 a fork and a spoon. 1221 00:47:42,520 --> 00:47:45,710 In order for that to make a difference whether you report 1222 00:47:45,710 --> 00:47:47,890 both are present-- so again, if you have a right sided 1223 00:47:47,890 --> 00:47:50,480 lesion, you might tend not to report this fork or not to 1224 00:47:50,480 --> 00:47:52,250 report this key. 1225 00:47:52,250 --> 00:47:55,650 If you just don't report either one, OK, left is left 1226 00:47:55,650 --> 00:47:56,870 and you're bad at reporting that one. 1227 00:47:56,870 --> 00:47:58,650 There's something competing in the good field. 1228 00:47:58,650 --> 00:48:02,560 Your attention gets drawn here, hard to disengage. 1229 00:48:02,560 --> 00:48:06,690 But if it makes a difference what this thing is, that means 1230 00:48:06,690 --> 00:48:09,920 that your mind kind of knows what it is. 1231 00:48:09,920 --> 00:48:13,980 And your mind is saying, well, if it's a key, that's 1232 00:48:13,980 --> 00:48:15,930 different enough that I can still pay attention to it. 1233 00:48:15,930 --> 00:48:19,240 But if it's another fork, those are really similar. 1234 00:48:19,240 --> 00:48:21,820 And now, my mind is really sucked into this fork. 1235 00:48:21,820 --> 00:48:24,020 But in order for that to make a difference, do you see that 1236 00:48:24,020 --> 00:48:26,650 you have to know somewhere in your mind what's different on 1237 00:48:26,650 --> 00:48:28,680 the left for that to affect your performance? 1238 00:48:28,680 --> 00:48:31,880 So now, we'll see a video of a patient, the last one. 1239 00:48:31,880 --> 00:48:36,270 This is a neurologist, Bob Rafal, and a patient. 1240 00:48:36,270 --> 00:48:39,150 It's a hugely nice thing of the patients, most of all, but 1241 00:48:39,150 --> 00:48:41,590 also the physicians to make these tapes available for 1242 00:48:41,590 --> 00:48:42,840 teaching purposes. 1243 00:48:48,920 --> 00:48:50,380 So you understand-- 1244 00:48:50,380 --> 00:48:52,420 just review for one month and we're done-- 1245 00:48:52,420 --> 00:48:55,470 that when the same object came up, did he pretty much notice 1246 00:48:55,470 --> 00:48:57,730 the one on the bad side and the right side for him? 1247 00:48:57,730 --> 00:48:58,600 No. 1248 00:48:58,600 --> 00:49:00,840 Same object, he almost always said it's one. 1249 00:49:00,840 --> 00:49:03,850 If they're different objects, he typically reported slightly 1250 00:49:03,850 --> 00:49:06,560 sluggishly the one on his bad side. 1251 00:49:06,560 --> 00:49:10,340 That means part of his mind has to know what the object is 1252 00:49:10,340 --> 00:49:14,700 so that he ignores it if it's identical and he reports it if 1253 00:49:14,700 --> 00:49:15,300 it's different. 1254 00:49:15,300 --> 00:49:17,390 Well, you have to know what it is to base 1255 00:49:17,390 --> 00:49:18,660 your answer on that. 1256 00:49:18,660 --> 00:49:22,490 Yet, the logic of neglect is that if they're identical, 1257 00:49:22,490 --> 00:49:24,710 then he's going to ignore the one that he spotted on the 1258 00:49:24,710 --> 00:49:28,300 left in part of his mind but squashed from his awareness on 1259 00:49:28,300 --> 00:49:29,085 the other side. 1260 00:49:29,085 --> 00:49:30,335 OK, thanks very much.