The Secret Life of the Mind

by Mariano Sigman

  The past and the future of consciousness

  Today, using the tools that allow us to infer thoughts from brain activity, it is possible to delve into dreams, into the mind of newborns and into the imagination of vegetative patients. But this technology is useless for investigating one of the most mysterious aspects of human thought: our predecessors’ consciousness. We know for certain that their brains were almost identical to ours. But in our prehistory there were no books, radio, television or cities. Life was much shorter, and focused on hunting and the vital matters of the present. Was consciousness different from ours in contemporary society? To put it another way, does consciousness–the way we perceive it today–emerge spontaneously in the brain’s development or is it forged in a particular cultural niche?

  We may all have different opinions and intuitions about this; actually it is a long-standing philosophical debate. When I first reflected about this question, I believed that it was not even amenable to science. But then it became quite obvious that in the same way that we can reconstruct what the Ancient Greeks’ cities looked like, on the basis of just a few bricks, the writings of a culture are archaeological records, fossils of human thought.

  And in fact, doing some form of psychological analysis on a number of the most ancient books in human culture, Julian Jaynes sought to answer the question, coming up with one of the most polemical and debated theories in cognitive neuroscience: that only 3,000 years ago the world was a garden of schizophrenics. That consciousness, as we perceive it today, where we feel we are the pilots of our own existence, emerged with culture only very recently in the history of humanity.

  The proliferation of the first books, in a period between 800 and 200 BC, coincided with radical transformations in three great civilizations in the world, Chinese, Indian and Western. It was during this period that the religions and philosophies that are the pillars of modern culture were produced. Studying two foundational texts of Western civilization, the Bible and the Homeric sagas, Julian Jaynes argued that consciousness was also transformed during this period.

  He made this claim based on the fact that the first humans described in these books behaved–in different traditions, in different places of the world–as if they were hearing and obeying voices… which they perceived as if they were coming from gods or muses. What today we would call hallucinations.

  And then, as time went on, they progressively began to understand that they were the creators and owners of these inner voices. And, with this, they acquired introspection: the ability to think about their own thoughts.

  The Canadian philosopher Marshall McLuhan argued that this change was a consequence of the appearance of written texts, because it allows thought to be consolidated on paper instead of being entrusted to the more volatile memory. Those who now reflect so much on how the Internet, tablets, mobile phones and the unceasing flow of information can change the way we think and feel should remember that the information age is not the first material revolution to radically change the way we express ourselves, communicate and, almost certainly, think.

  For Jaynes, consciousness, prior to Homer, lived in the present and didn’t recognize that each of us is the author of our own voices. That is what we call primary consciousness, which today is characteristic of schizophrenia or dreams (except for lucid ones). With the proliferation of texts, consciousness transformed into what we now recognize. We feel we are the authors, protagonists, and those responsible for our mental creations, which in turn have the richness to interweave with what we know of the past and what we predict or hope for the future. And we are capable of introspection: we can think and reflect on our thoughts.

  When I first heard about Jaynes’s theory, I thought that it was quite spectacular, because of its capacity to put some order in the history of our own thoughts, and its wild conjecture that consciousness may have been experienced in a completely different way at different moments of our history. But it had an obvious problem. It was based on just a few very specific examples and felt a bit like drawing constellations in the sky.

  With Guillermo Cecchi, my brother for many years in this adventure in science, and with two computer scientists, Carlos Diuk and Diego Slezak, we decided to work out how this hypothesis could be examined in a quantitative and objective manner. And the problem of how to go about this is quite obvious: it is not like Plato woke up one day and wrote: Hello, I´m Plato, as of today I have a fully introspective consciousness. And this tells us what the essence of the problem is. We need to find the emergence of a concept that is never said. The word introspection is not mentioned one single time in the books we were analysing.

  Our way to solve this was to construct the space of words: a very complex space in which all words are arranged so that the proximity of two words is indicative of how closely related they are. We would want in this space the words ‘dog’ and ‘cat’ to be close together, but the words grapefruit and logarithm to be very far apart. And this has to be true for any two words in this space.

  There are different ways to build this space. One is to ask the experts, just as we do with dictionaries. Another way is to follow the simple assumption that when two words are related, they tend to appear in the same sentence, paragraph or document more frequently than they would be expected to just by pure chance. And actually this simple method, with some computational tricks to deal with this huge and high-dimensional space, turns out to be very effective.

  Once we have built this space, the question of the history of introspection, or of any other concept, which seemed abstract and somehow vague, becomes concrete, and amenable to quantitative science. All that needs to be done is to take a text, digitize it, project the stream of words in a trajectory on to this space and ask whether it spends significant time circling closely to the concept of introspection. The word introspection may never be said, but if words like self, guilt, reason, emotion become frequent then the text will be closer to introspection. This is how the algorithm can read in between the lines.

  And with this we could analyse the history of introspection in the Ancient Greek tradition for which we have the best available written record. We took all books, ordered them by time, measured the proximity of each word to introspection, and calculated the averages, and then we were able to show that as time goes on there is a slow progression for the older Homeric texts: the Iliad and the Odyssey. And then, about 600 years before Christ, throughout the development of the Ancient Greek culture, the frequency begins to rise very rapidly to an almost fivefold increase and writings become closer and closer to introspection.

  And the nice thing about using an objective procedure is that we can ask whether these results are also true in a different and independent tradition. So we repeated this analysis for the Judeo-Christian books, and we saw essentially the same pattern: a slow progression through the Old Testament with words getting closer and closer to introspection, and their use growing more rapidly throughout the course of the New Testament. Introspection peaks in the writings of Saint Augustine, about four centuries after Christ.*

  This is very important, because Saint Augustine is widely recognized by scholars as one of the founders of introspection. (Actually some consider him to be one of the fathers of modern psychology.) So this algorithm, which has the virtue of being objective, quantitative and, of course, incredibly fast, can capture some of the most important conclusions of a long tradition of investigation.

  One of the most relevant consequences of having converted this quest into objective science is that this idea can be translated and generalized to a whole range of different domains. And in the same way we used it to ask about the past of human consciousness, maybe the most challenging question we can ask is whether it can say something about the future of our own consciousness.

  To put it more precisely, can the words we say today tell us something about where our minds will be a few months or even a few years from now? In the same way that many of us wear sensors (that detect our heart rate, our
respiration, our genes), hoping that this information may help us prevent diseases, we can ask whether monitoring and analysing the words we speak, we write, we tweet, may enable us to detect ahead of time when something might go wrong with our minds.

  Guillermo Cecchi, in IBM Watson, put together a group of psychiatrists and computer scientists that spread from New York to Brazil and Argentina (often referred to humorously as the Armada Brancaleone) to take on this challenge.

  We analysed the recorded speech of thirty-four young people who were at a high risk of developing schizophrenia. The question was whether properties of speech at day one could predict the onset of psychosis within a window of almost three years.

  It turned out that there was just not enough information in semantics to predict the future organization of the mind. But this, in fact, was expected. One of the most distinctive features of schizophrenics is disorganized speech. Hence, the most important thing was not what they were saying, but how they were saying it. More precisely, it did not matter so much in what semantic neighbourhood the words were, but instead how far and fast they jumped in fluent speech from one neighbourhood to another. So we came up with a measurement that we termed semantic coherence, which grades the persistence of speech in one semantic topic.

  And it turned out that in our group of thirty-four participants the algorithm based on semantic coherence could predict with close to perfect accuracy who would develop psychosis and who would not, something that could not be achieved by any other existing clinical measure. This is as yet a preliminary study of a relatively small group and needs to be replicated on a much larger cohort to calibrate its real efficacy, and the conditions in which it is most effective (how much speech, oral or written, structured interview or free …).

  I was asked in 2016 to give a TED talk about this work. On preparing the talk I remember very vividly one day on which I saw a long series of tweets from Polo, one of my students in Buenos Aires who at the time was living in New York. There was something about these tweets. I could not tell exactly what, because they did not express anything explicitly. But I had a strong hunch, a strong intuition, that something was going wrong. So I took the phone and called Polo, and in fact he was not feeling well.

  And this simple fact, that reading in between the lines I could sense through words his feelings, was a simple but effective way to help. In a way, I like to think that the most relevant aspect of this work is that it gets us closer to understanding how to convert this intuition, that we all have, that we all share, into an algorithm. And with this we may be seeing in the future a very different form of mental health, based on an automated, objective and quantitative analysis of the words we write, of the words we say.

  The future of consciousness: is there a limit to mind-reading?

  Today Freud would no longer be working in the dark. We have tools that allow us to access the thoughts–conscious or not–of vegetative patients and babies. And we can investigate the contents of a dreamer’s dream. Will we soon be able to record our dreams and visualize them while awake, as in a film, in order to reproduce everything that, up until now, vanishes upon waking?

  Reading others’ minds by decoding mental states through their corresponding cerebral patterns is like tapping a phone line, cracking a code and entering into someone else’s private world. This possibility opens perspectives and possibilities but also dangers and risks.* After all, if anything is private, it’s our thoughts. Soon, perhaps, they no longer will be.

  The resolution of today’s tools is limited and barely allows us to recognize a few fragments of thought. In a not-so-distant future it is possible we could be able to write and read sensations directly from the biological substratum that produces them: the brain. And we will almost certainly be able to observe the contents of the mind deep in the most remote corners of the unconscious.

  This path seems to have no end, as if it were only a question of improving the technology. Is that how it will pan out? Or is there a structural limit to our ability to observe our own and others’ thoughts? In nature, as we know it, there are limits to our ability for observation. We cannot communicate faster than the speed of light, no matter what the technology. Nor can we, according to the laws of quantum mechanics, access all the information in a particle–not even its position and its speed–with absolute precision. Nor can we enter–or, more accurately, exit–a black hole. These are not temporary problems due to a lack of the proper technology. If our current knowledge of physics is correct, these limits are insurmountable despite any technological development. Will there be a similar limit to our ability to observe our own thoughts?

  My friend and colleague the Swedish philosopher Kathinka Evers and I argue that there is a natural limit to our inspection of the human mind. The adventure can be extremely enriching–in some cases, liberating, as with vegetative patients–but it is likely that there is an intrinsic limit to our ability to investigate thought, one that goes beyond the limits of the technological precision of the tools with which we are examining it.

  There are two philosophical arguments that allow us to suspect that there is a limit to our capacity to observe ourselves. The first is that each thought is unique and never repeats. In philosophy, the type/token distinction separates the types as a concept and an abstract object from the token, which is the realization, or instantiation, or occurrence of the type. One can think twice about the same dog, even in the same place and in the same light, but they are still two different thoughts. The second philosophical objection stems from a logical argument known as Leibniz’s Law, which maintains that a subject is, at least in some way, unique and different from others. When an observer decodes another’s mental states with maximum resolution, they do so from their own perspective, with their own nuances and overtones. In other words, the human mind has an impregnable sphere of privacy. Perhaps at some future time that sphere may become very small, but it cannot be eliminated altogether. If someone were to entirely access someone else’s mental contents, then they would be that someone else. The two would meld. They would become one.

  CHAPTER FIVE

  The Brain is Constantly Transforming

  What makes our brain more or less predisposed to change?

  Is it true that it’s much harder to learn things–like a new language or to play an instrument–when we are older? Why is it easy for some of us to learn music and so difficult for others? Why do we all learn to speak naturally, and yet many of us struggle with maths? Why is learning some things so arduous and others so simple?

  In this chapter we will navigate into the history of learning, effort and virtue, mnemonic techniques, the drastic cerebral transformation when we learn to read, and our brain’s capacity for change.

  Virtue, oblivion, learning, and memory

  Plato tells of a stroll in fifth-century BC Athens during which Socrates and Menon heatedly discussed virtue. Is it possible to learn it? If so, how? In the midst of the debate, Socrates presents a phenomenal argument: virtue cannot be learned. What’s more, nothing can be learned. Each of us already possesses all knowledge. So learning actually means remembering.* This conjecture, so beautiful and bold, was implanted in different versions of Socratic teaching in thousands and thousands of classrooms across the world.

  It’s strange. The great master of antiquity was questioning the more intuitive version of education. Teaching is not transmitting knowledge but rather teachers help their students to express and evoke knowledge they already have. This argument is central to Socratic thought. According to him, at each birth, one of the many souls wandering about in the land of the gods descends to confine itself within the newborn body. Along the way it crosses the River Lethe, where it forgets everything it knew. It all begins with oblivion. The path of life, and of pedagogy, is a constant remembering of that which we forgot when crossing the Lethe.

  Socrates proposed to Menon that even the most ignorant of slaves already knows the mysteries of virtue and the most sophisticated elements of
maths and geometry. When Menon showed his incredulity, Socrates did something extraordinary, he suggested resolving the discussion in the realm of experiments.

  The universals of human thought

  Menon then called over one of his slaves, who became the unexpected protagonist of a formidable landmark in the history of education. Socrates drew a square in the sand and fired off a volley of questions. Just as mathematical works are a record of the most refined and elaborate Greek thought, Menon’s slave’s answers revealed the popular intuitions, the common sense, of the period.

  In the first key passage of the dialogue, Socrates asks: ‘How must I change the length of the sides so a square’s area doubles?’ Think of an answer quickly, make a hunch without getting into elaborate reflection. That is probably what the slave did when he responded: ‘I simply double the length of the sides.’ Then Socrates proceeded to draw the new square in the sand and the slave discovered that it was made up of four squares identical to the original one.

  The slave then discovered that doubling the side of the square quadrupled its area. And Socrates continued his question-and-answer game. Along the way, by responding on the basis of what he already knew, the slave expressed the geometrical principles that he intuited. And he was able to learn from his own errors and correct them.

  Towards the end of the dialogue, Socrates drew a new square in the sand, whose side was the diagonal of the original square.

  And then the slave could clearly see that it was made up of four triangles, while the original was made up of only two.