WEBVTT 00:00:01.102 --> 00:00:06.180 We have historical records that allow us to know how the ancient Greeks dressed, 00:00:06.180 --> 00:00:07.458 how they lived, 00:00:07.458 --> 00:00:09.159 how they fought ... 00:00:09.159 --> 00:00:11.211 but how did they think? NOTE Paragraph 00:00:11.535 --> 00:00:16.094 One natural idea is that the deepest aspects of human thought -- 00:00:16.094 --> 00:00:17.976 our ability to imagine, 00:00:17.976 --> 00:00:19.306 to be conscious, 00:00:19.306 --> 00:00:20.681 to dream -- 00:00:20.681 --> 00:00:22.701 have always been the same. 00:00:23.092 --> 00:00:24.601 Another possibility 00:00:24.601 --> 00:00:28.351 is that the social transformations that have shaped our culture 00:00:28.351 --> 00:00:32.428 may have also changed the structural columns of human thought. NOTE Paragraph 00:00:33.096 --> 00:00:35.627 We may all have different opinions about this. 00:00:35.627 --> 00:00:38.344 Actually, it's a long-standing philosophical debate. 00:00:38.724 --> 00:00:42.335 But is this question even amenable to science? NOTE Paragraph 00:00:43.116 --> 00:00:45.555 Here I'd like to propose 00:00:45.555 --> 00:00:50.160 that in the same way we can reconstruct how the ancient Greek cities looked like 00:00:50.160 --> 00:00:52.777 just based on a few bricks, 00:00:52.777 --> 00:00:56.835 that the writings of a culture are the archeological records -- 00:00:56.835 --> 00:00:59.467 the fossils of human thought. NOTE Paragraph 00:01:00.199 --> 00:01:01.390 And in fact, 00:01:01.390 --> 00:01:03.570 doing some form of psychological analysis 00:01:03.570 --> 00:01:07.184 of some of the most ancient books of human culture, 00:01:07.184 --> 00:01:13.028 Julian Jaynes came in the '70s with a very wild and radical hypothesis ... 00:01:13.028 --> 00:01:15.444 that only 3,000 years ago, 00:01:15.444 --> 00:01:20.857 humans were what today we would call schizophrenics. 00:01:21.883 --> 00:01:23.575 And he made this claim 00:01:23.575 --> 00:01:26.752 based on the fact that the first humans [inscribing] these books 00:01:26.752 --> 00:01:28.792 behaved consistently, 00:01:28.792 --> 00:01:31.708 in different traditions and in different places of the world, 00:01:31.708 --> 00:01:35.444 as if they were hearing and obeying voices 00:01:35.444 --> 00:01:38.394 that they perceived as coming from the Gods, 00:01:38.394 --> 00:01:40.413 or from the muses -- 00:01:40.413 --> 00:01:43.673 what today we would call hallucinations. 00:01:44.012 --> 00:01:45.476 And only then, 00:01:45.476 --> 00:01:46.780 as time went on, 00:01:46.780 --> 00:01:50.361 they began to recognize that they were the creators -- 00:01:50.361 --> 00:01:53.078 the owners of these inner voices. 00:01:53.510 --> 00:01:56.273 And with this they gained introspection: 00:01:56.273 --> 00:01:59.221 the ability to think about their own thoughts. NOTE Paragraph 00:01:59.965 --> 00:02:03.378 So Jaynes' theory is that consciousness -- 00:02:03.378 --> 00:02:06.538 at least in the way we perceive it today, 00:02:06.538 --> 00:02:10.225 where we feel that we are the pilots of our own existence -- 00:02:10.225 --> 00:02:13.164 is a quite recent cultural development. 00:02:13.545 --> 00:02:15.337 And this theory is quite spectacular, 00:02:15.337 --> 00:02:16.769 but it has an obvious problem 00:02:16.769 --> 00:02:20.761 which is that it's built on just a few and very specific examples. 00:02:21.085 --> 00:02:22.872 So the question is whether the theory 00:02:22.872 --> 00:02:27.913 that introspection built up in human history only about 3,000 years ago 00:02:27.913 --> 00:02:31.283 can be examined in a quantitative and objective manner. NOTE Paragraph 00:02:31.779 --> 00:02:35.338 And the problem on how to go about this is quite obvious. 00:02:35.338 --> 00:02:37.724 It's not like Plato woke up one day 00:02:37.724 --> 00:02:38.910 and then he wrote, 00:02:38.910 --> 00:02:40.596 "Hello, I'm Plato 00:02:40.596 --> 00:02:43.487 and as of today I have a fully introspective consciousness." NOTE Paragraph 00:02:43.487 --> 00:02:45.307 (Laughter) NOTE Paragraph 00:02:45.637 --> 00:02:49.097 And this still is actually what is the essence of the problem. 00:02:49.624 --> 00:02:54.071 We need to find the emergence of a concept that's never said. 00:02:54.680 --> 00:02:58.942 The word introspection does not appear a single time 00:02:58.942 --> 00:03:01.559 in the books we want to analyze. NOTE Paragraph 00:03:01.971 --> 00:03:06.398 So our way to solve this is to build the space of words. 00:03:06.794 --> 00:03:09.998 This is a huge space that contains all words 00:03:09.998 --> 00:03:12.959 in such a way that they distance between any two of them 00:03:12.959 --> 00:03:15.842 is indicative of how closely related they are. 00:03:16.460 --> 00:03:17.456 So for instance, 00:03:17.456 --> 00:03:20.857 you want the words dog and cat to be very close together, 00:03:20.857 --> 00:03:24.688 but the words grapefruit and logarithm to be very far away. 00:03:25.008 --> 00:03:29.298 And this has to be true for any two words within the space. NOTE Paragraph 00:03:29.748 --> 00:03:33.109 And there are different ways that we can construct the space of words. 00:03:33.109 --> 00:03:34.802 One is just asking the experts, 00:03:34.802 --> 00:03:37.199 a bit like we do with dictionaries. 00:03:37.199 --> 00:03:38.623 Another possibility 00:03:38.623 --> 00:03:40.688 is following the simple assumption 00:03:40.688 --> 00:03:44.640 that when two words are related they tend to appear in the same sentences, 00:03:44.640 --> 00:03:46.214 in the same paragraphs, 00:03:46.214 --> 00:03:48.049 in the same documents, 00:03:48.049 --> 00:03:51.509 more often than would be expected just by pure chance. 00:03:52.448 --> 00:03:54.305 And this simple hypothesis, 00:03:54.305 --> 00:03:55.792 this simple method, 00:03:55.792 --> 00:03:57.266 with some computational tricks 00:03:57.266 --> 00:03:58.679 that have to do with the fact 00:03:58.679 --> 00:04:01.995 that this is a very complex and highly dimensional space, 00:04:01.995 --> 00:04:04.458 turns out to be quite effective. NOTE Paragraph 00:04:04.458 --> 00:04:07.127 And just to give you a flavor of how well this works, 00:04:07.127 --> 00:04:11.321 this is the result we get when we analyze this for some familiar words. 00:04:11.607 --> 00:04:12.816 And you can see first 00:04:12.816 --> 00:04:16.278 that words automatically organize into semantic neighborhoods. 00:04:16.278 --> 00:04:17.362 So you get the fruits, 00:04:17.362 --> 00:04:18.359 the body parts, 00:04:18.359 --> 00:04:19.360 the computer parts, 00:04:19.360 --> 00:04:20.359 the scientific terms 00:04:20.359 --> 00:04:21.357 and so on. NOTE Paragraph 00:04:21.357 --> 00:04:25.699 The algorithm also identifies the reorganized concepts in a hierarchy. 00:04:26.027 --> 00:04:27.027 So for instance, 00:04:27.027 --> 00:04:30.648 you can see that the scientific terms break down into two subcategories 00:04:30.648 --> 00:04:33.608 of the astronomic and the physic terms. 00:04:33.608 --> 00:04:35.881 And then there are very fine things. 00:04:35.881 --> 00:04:36.878 For instance, 00:04:36.878 --> 00:04:38.054 the word astronomy, 00:04:38.056 --> 00:04:39.870 which seems a bit bizarre where it is, 00:04:39.870 --> 00:04:41.768 is actually exactly where it should be, 00:04:41.768 --> 00:04:43.219 between what it is -- 00:04:43.219 --> 00:04:44.630 an actual science -- 00:04:44.630 --> 00:04:46.165 and between what it describes -- 00:04:46.165 --> 00:04:47.912 the astronomical terms. NOTE Paragraph 00:04:48.366 --> 00:04:50.097 And we could go on and on with this. 00:04:50.097 --> 00:04:52.181 Actually if you stare at this for a while 00:04:52.181 --> 00:04:54.034 and you just build random trajectories, 00:04:54.034 --> 00:04:55.725 you will see that is feels well -- 00:04:55.725 --> 00:04:58.286 actually it feels a bit like doing poetry. 00:04:58.286 --> 00:04:59.286 And this is because, 00:04:59.286 --> 00:05:00.288 in a way, 00:05:00.288 --> 00:05:03.482 walking in this space is like walking in the mind. NOTE Paragraph 00:05:03.901 --> 00:05:05.778 And the last thing 00:05:05.778 --> 00:05:09.938 is that this algorithm identifies what are our intuitions 00:05:09.938 --> 00:05:14.002 of which words should lead in the neighborhood of introspection. 00:05:14.002 --> 00:05:15.072 So for instance, 00:05:15.072 --> 00:05:18.982 words such as self, guilt, reason, emotion, 00:05:18.982 --> 00:05:21.102 are very close to introspection, 00:05:21.102 --> 00:05:22.102 but other words, 00:05:22.102 --> 00:05:24.432 such as red, football, candle, banana, 00:05:24.432 --> 00:05:26.072 are just very far away. NOTE Paragraph 00:05:26.262 --> 00:05:28.882 And so once we've built the space, 00:05:28.882 --> 00:05:31.945 the question of the history of introspection, 00:05:31.945 --> 00:05:34.277 or of the history of any concept 00:05:34.277 --> 00:05:39.055 which before could seem abstract and somehow vague, 00:05:39.055 --> 00:05:40.754 becomes concrete -- 00:05:40.754 --> 00:05:43.656 becomes amenable to quantitative science. NOTE Paragraph 00:05:44.481 --> 00:05:47.137 All that we have to do is take the books, 00:05:47.137 --> 00:05:48.612 we digitize them, 00:05:48.612 --> 00:05:51.420 and we take this stream of words as a trajectory 00:05:51.420 --> 00:05:53.452 and project them into the space, 00:05:53.452 --> 00:05:57.087 and then we ask whether this trajectory spends significant time 00:05:57.087 --> 00:06:00.361 circling closely to the concept of introspection. NOTE Paragraph 00:06:00.911 --> 00:06:02.152 And with this, 00:06:02.152 --> 00:06:04.263 we could analyze the history of introspection 00:06:04.263 --> 00:06:06.183 in the ancient Greek tradition, 00:06:06.183 --> 00:06:09.304 for which we have the best available written record. 00:06:09.711 --> 00:06:12.131 So what we did is we took all the books -- 00:06:12.131 --> 00:06:14.517 we just ordered them by time -- 00:06:14.517 --> 00:06:15.994 for each book we take the words 00:06:15.994 --> 00:06:18.194 and we project them to the space, 00:06:18.194 --> 00:06:21.165 and then we ask for each word how close it is to introspection, 00:06:21.165 --> 00:06:22.728 and we just average that. 00:06:22.728 --> 00:06:25.986 And then we understand that as time goes on and on, 00:06:25.986 --> 00:06:29.088 these books get closer, and closer and closer 00:06:29.088 --> 00:06:31.062 to the concept of introspection. NOTE Paragraph 00:06:31.062 --> 00:06:35.387 And this is exactly what happens in the ancient Greek tradition. 00:06:35.968 --> 00:06:39.146 So you can see that for the oldest books in the Homeric tradition, 00:06:39.146 --> 00:06:42.540 there is a small increase with books getting closer to introspection, 00:06:42.540 --> 00:06:44.816 but about four centuries before Christ, 00:06:44.816 --> 00:06:49.376 this starts ramping-up very rapidly to an almost five-fold increase 00:06:49.376 --> 00:06:51.938 of books getting closer, and closer and closer 00:06:51.938 --> 00:06:54.319 to the concept of introspection. 00:06:54.319 --> 00:06:56.679 And one of the nice things about this 00:06:56.679 --> 00:06:57.829 is that now we can ask 00:06:57.829 --> 00:07:02.498 whether this is also true in a different independent tradition. NOTE Paragraph 00:07:03.026 --> 00:07:06.248 So we just ran this same analysis on the Judeo-Christian tradition, 00:07:06.248 --> 00:07:09.178 and we got virtually the same pattern. 00:07:09.741 --> 00:07:14.445 Again you see a small increase for the oldest books in the Old Testament, 00:07:14.445 --> 00:07:16.326 and then it increases much more rapidly 00:07:16.326 --> 00:07:18.169 in the new books of the New Testament, 00:07:18.169 --> 00:07:20.518 and then we get the peak of introspection 00:07:20.518 --> 00:07:22.521 in the work Confessions of Saint Augustine, 00:07:22.521 --> 00:07:24.721 about four centuries after Christ. 00:07:25.051 --> 00:07:26.985 And this was very important, 00:07:26.985 --> 00:07:30.351 because Saint Augustine had been recognized by scholars -- 00:07:30.351 --> 00:07:31.481 philologists, 00:07:31.481 --> 00:07:32.632 historians -- 00:07:32.632 --> 00:07:35.298 as one of the founders of introspection. 00:07:35.298 --> 00:07:38.595 Actually, some believe him to be the father of modern psychology. NOTE Paragraph 00:07:39.155 --> 00:07:41.157 So our algorithm, 00:07:41.157 --> 00:07:43.804 which has the virtue of being quantitative, 00:07:43.804 --> 00:07:45.066 of being objective, 00:07:45.066 --> 00:07:47.332 and of course of being extremely fast -- 00:07:47.332 --> 00:07:49.636 it just runs in a fraction of a second -- 00:07:49.636 --> 00:07:53.138 can capture some of the most important conclusions 00:07:53.138 --> 00:07:55.940 of this long tradition of investigation. 00:07:56.547 --> 00:08:00.142 And this is in a way one of the beauties of science, 00:08:00.142 --> 00:08:03.617 which is that now this idea can be translated 00:08:03.617 --> 00:08:06.496 and generalized to a whole lot of different domains. NOTE Paragraph 00:08:06.920 --> 00:08:11.807 So in the same way that we asked about the past of human conciousness, 00:08:11.807 --> 00:08:15.132 maybe the most challenging question we can pose to ourselves, 00:08:15.132 --> 00:08:19.269 is whether this can tell us something about the future of our own consciousness. 00:08:19.717 --> 00:08:21.186 To put it more precisely, 00:08:21.186 --> 00:08:23.601 whether the words we say today 00:08:23.601 --> 00:08:28.797 can tell us something of where our minds will be in a few days, 00:08:28.797 --> 00:08:29.962 in a few months, 00:08:29.962 --> 00:08:31.907 or a few years from now. NOTE Paragraph 00:08:31.907 --> 00:08:34.813 And in the same way many of us are now wearing censors 00:08:34.813 --> 00:08:36.524 that detect our heart rate, 00:08:36.524 --> 00:08:37.936 our respiration, 00:08:37.936 --> 00:08:39.712 our genes, 00:08:39.712 --> 00:08:43.268 on the hopes that this may help us prevent diseases, 00:08:43.268 --> 00:08:46.788 we can ask whether monitoring and analyzing the words we speak -- 00:08:46.788 --> 00:08:47.786 we tweet, 00:08:47.786 --> 00:08:48.789 we email, 00:08:48.789 --> 00:08:49.793 we write -- 00:08:49.793 --> 00:08:54.759 can tell us ahead of time whether something may go wrong with our minds. 00:08:55.301 --> 00:08:56.834 And with Guillermo Cecci, 00:08:56.834 --> 00:08:59.962 who has been my brother in this adventure, 00:08:59.962 --> 00:09:01.517 we took on this task. 00:09:02.489 --> 00:09:08.054 And we did so by analyzing the recorded speech of 34 young people 00:09:08.054 --> 00:09:11.168 who were at a high risk of developing schizophrenia. NOTE Paragraph 00:09:11.568 --> 00:09:14.502 And so what we did is we measured speech at day one 00:09:14.502 --> 00:09:17.743 and then we asked whether the properties of the speech could predict, 00:09:17.743 --> 00:09:20.238 within a window of almost three years, 00:09:20.238 --> 00:09:22.919 the future development of psychosis. 00:09:23.570 --> 00:09:26.039 But despite our hopes, 00:09:26.039 --> 00:09:29.568 we got failure after failure. 00:09:29.928 --> 00:09:33.801 There was just not enough information in semantics 00:09:33.801 --> 00:09:36.844 to predict the future organization of the mind. 00:09:36.844 --> 00:09:38.556 It was good enough 00:09:38.556 --> 00:09:42.883 to distinguish between a group of schizophrenics and a control group, 00:09:42.883 --> 00:09:45.555 a bit like we had done for the ancient texts, 00:09:45.555 --> 00:09:49.108 but not to predict the future onto the psychosis. NOTE Paragraph 00:09:49.320 --> 00:09:51.109 But then we realized 00:09:51.109 --> 00:09:55.135 that maybe the most important thing was not so much what they were saying 00:09:55.135 --> 00:09:57.322 but how they were saying it. 00:09:57.778 --> 00:09:59.138 More specifically, 00:09:59.138 --> 00:10:02.012 it was not in which semantic neighborhoods the words were, 00:10:02.012 --> 00:10:04.611 but how far and fast they jumped 00:10:04.611 --> 00:10:07.076 from one semantic neighborhood to the other one. 00:10:07.336 --> 00:10:09.065 And so we came up with this measure, 00:10:09.065 --> 00:10:11.624 which we termed semantic coherence, 00:10:11.624 --> 00:10:16.427 which essentially measures the persistence of speech within one semantic topic, 00:10:16.427 --> 00:10:18.770 within one semantic category. NOTE Paragraph 00:10:19.445 --> 00:10:23.502 And it turned out to be that for this group of 34 people, 00:10:23.502 --> 00:10:27.465 the algorithm based on semantic coherence could predict, 00:10:27.465 --> 00:10:29.630 with 100 percent accuracy, 00:10:29.630 --> 00:10:32.700 who developed psychosis and who will not. 00:10:33.178 --> 00:10:36.150 And this was something that could not be achieved -- 00:10:36.150 --> 00:10:37.733 not even close -- 00:10:37.733 --> 00:10:41.123 with all the other existing clinical measures. NOTE Paragraph 00:10:42.779 --> 00:10:46.401 And I remember vividly while I was working on this, 00:10:46.401 --> 00:10:48.750 I was sitting on my computer 00:10:48.750 --> 00:10:51.219 and I saw a bunch of tweets by Polo -- 00:10:51.219 --> 00:10:54.385 Polo had been my first student back in Buenos Aires 00:10:54.385 --> 00:10:56.413 and at the time he was living in New York. 00:10:56.413 --> 00:10:58.613 And there was something in this tweets -- 00:10:58.613 --> 00:11:02.273 I could not tell exactly what because nothing was said explicitly -- 00:11:02.273 --> 00:11:04.293 but I got this strong hunch, 00:11:04.293 --> 00:11:07.873 this strong intuition that something was going wrong. 00:11:08.510 --> 00:11:11.094 So I picked up the phone and I called Polo, 00:11:11.094 --> 00:11:13.300 and in fact he was not feeling well. 00:11:13.582 --> 00:11:15.544 And this simple fact 00:11:15.544 --> 00:11:18.004 that reading in between the lines 00:11:18.004 --> 00:11:22.224 I could sense through words his feelings, 00:11:22.224 --> 00:11:25.196 was a simple but very effective way to help. NOTE Paragraph 00:11:26.154 --> 00:11:27.905 What I tell you today 00:11:27.905 --> 00:11:30.587 is that we're getting close to understanding 00:11:30.587 --> 00:11:34.607 how we can convert this intuition that we all have, 00:11:34.607 --> 00:11:36.125 that we all share, 00:11:36.125 --> 00:11:37.801 into an algorithm. 00:11:38.264 --> 00:11:39.840 And in doing so, 00:11:39.840 --> 00:11:44.489 we may be seeing in the future a very different form of mental health, 00:11:44.489 --> 00:11:50.073 based on objective, quantitative and automated analysis 00:11:50.073 --> 00:11:51.934 of the words we write, 00:11:51.934 --> 00:11:53.470 of the words we say. NOTE Paragraph 00:11:53.470 --> 00:11:54.738 Gracias. NOTE Paragraph 00:11:54.738 --> 00:11:56.736 (Applause)