9:59:59.000,9:59:59.000
We have historical records that allow us[br]to know how the ancient Greeks dressed,

9:59:59.000,9:59:59.000
how they lived,

9:59:59.000,9:59:59.000
how they fought.

9:59:59.000,9:59:59.000
But how did they think?

9:59:59.000,9:59:59.000
One natural idea is that the deepest[br]aspects of human thought,

9:59:59.000,9:59:59.000
out ability to imagine,

9:59:59.000,9:59:59.000
to be concious,

9:59:59.000,9:59:59.000
to dream,

9:59:59.000,9:59:59.000
have always been the same.

9:59:59.000,9:59:59.000
Another possibility

9:59:59.000,9:59:59.000
is that the social transformations[br]that have shaped our culture

9:59:59.000,9:59:59.000
make us also change the structural[br]columns of human thought.

9:59:59.000,9:59:59.000
We may all have different[br]opinions about this.

9:59:59.000,9:59:59.000
Actually, it's a longstanding[br]philosophical debate.

9:59:59.000,9:59:59.000
But is this question[br]even amenable to science?

9:59:59.000,9:59:59.000
Here I'd like to propose that in the same way

9:59:59.000,9:59:59.000
that in the same way[br]that we can reconstruct

9:59:59.000,9:59:59.000
how the ancient Greek cities looked like,

9:59:59.000,9:59:59.000
just based on a few bricks,

9:59:59.000,9:59:59.000
that the writings of a culture[br]are the archealogical records --

9:59:59.000,9:59:59.000
the fossils --

9:59:59.000,9:59:59.000
of human thought.

9:59:59.000,9:59:59.000
And in fact,

9:59:59.000,9:59:59.000
doing some form of psychological analysis

9:59:59.000,9:59:59.000
of some of the most ancient[br]books of human culture,

9:59:59.000,9:59:59.000
Julian James came in the '70s[br]with a very wild and radical hypothesis,

9:59:59.000,9:59:59.000
that only 3,000 years ago,

9:59:59.000,9:59:59.000
humans were today[br]what we'd call, schizophrenics.

9:59:59.000,9:59:59.000
And he made this claim

9:59:59.000,9:59:59.000
based on the fact that the first humans[br]writing these books behaved consistently

9:59:59.000,9:59:59.000
in different traditions and in different[br]places of the world,

9:59:59.000,9:59:59.000
as if they were hearing and obeying voices

9:59:59.000,9:59:59.000
that they perceived[br]as coming from the Gods,

9:59:59.000,9:59:59.000
or from the muses.

9:59:59.000,9:59:59.000
What today we'd call hallucinations.

9:59:59.000,9:59:59.000
And only then,

9:59:59.000,9:59:59.000
as time went on,

9:59:59.000,9:59:59.000
they began to recognize[br]that they were the creators --

9:59:59.000,9:59:59.000
the owners of these inner voices.

9:59:59.000,9:59:59.000
And with this they gained introspection:

9:59:59.000,9:59:59.000
the ability to think[br]about their own thoughts.

9:59:59.000,9:59:59.000
So Jaynes' theory is that conciousness,

9:59:59.000,9:59:59.000
at least in the way we perceive it today,

9:59:59.000,9:59:59.000
where we feel that we are the pilots[br]of our own existence,

9:59:59.000,9:59:59.000
is a quite recent cultural development.

9:59:59.000,9:59:59.000
And this theory is quite spectacular,

9:59:59.000,9:59:59.000
because an obvious problem,

9:59:59.000,9:59:59.000
which is that it's built on just a few[br]and very specific examples.

9:59:59.000,9:59:59.000
So the question is

9:59:59.000,9:59:59.000
whether the theory that introspection[br]built up only about 3,000 years ago,

9:59:59.000,9:59:59.000
can be examined in a quantitative[br]and objective way.

9:59:59.000,9:59:59.000
And the problem on how[br]to go about this is quite obvious.

9:59:59.000,9:59:59.000
It's not like Plato woke up one day

9:59:59.000,9:59:59.000
and then he wrote,

9:59:59.000,9:59:59.000
"Hello, I'm Plato

9:59:59.000,9:59:59.000
and as of today I have a fully[br]introspective consciousness."

9:59:59.000,9:59:59.000
(Laughter)

9:59:59.000,9:59:59.000
And this still is actually[br]what is the essence of the problem.

9:59:59.000,9:59:59.000
We need to find the emergence[br]of a concept that's never said.

9:59:59.000,9:59:59.000
The word introspection[br]does not appear a single time

9:59:59.000,9:59:59.000
in the books we want to analyze.

9:59:59.000,9:59:59.000
So our way to solve this[br]is to build the space of words.

9:59:59.000,9:59:59.000
This is a huge space[br]that contains all words

9:59:59.000,9:59:59.000
in such a way that they distance[br]between any two of them

9:59:59.000,9:59:59.000
is indicative of how[br]closely related they are.

9:59:59.000,9:59:59.000
So for instance,

9:59:59.000,9:59:59.000
you want the words dog and cat[br]to be very close together,

9:59:59.000,9:59:59.000
but the words grapefruit and logarithm[br]to be very far away.

9:59:59.000,9:59:59.000
And this has to be true for any[br]two words within the space.

9:59:59.000,9:59:59.000
And there are different ways that we[br]can construct the space of words.

9:59:59.000,9:59:59.000
One is just asking the experts,

9:59:59.000,9:59:59.000
a bit like we do with dictionaries.

9:59:59.000,9:59:59.000
Another possibility

9:59:59.000,9:59:59.000
is following the simple assumption

9:59:59.000,9:59:59.000
that when two words are related[br]they tend to appear in the same sentences,

9:59:59.000,9:59:59.000
in the same paragraphs,

9:59:59.000,9:59:59.000
in the same documents,

9:59:59.000,9:59:59.000
more often than would be expected[br]just by pure chance.

9:59:59.000,9:59:59.000
And this simple hypothesis,

9:59:59.000,9:59:59.000
this simple method,

9:59:59.000,9:59:59.000
with some computational tricks

9:59:59.000,9:59:59.000
that have to do with the fact

9:59:59.000,9:59:59.000
that this is a very complex[br]and highly dimensional space,

9:59:59.000,9:59:59.000
turns out to be quite effective.

9:59:59.000,9:59:59.000
And just to give you a flavor[br]of how well this works,

9:59:59.000,9:59:59.000
this is the result we get when[br]we analyze this for some familiar words.

9:59:59.000,9:59:59.000
And you can see first

9:59:59.000,9:59:59.000
that words automatically organize[br]into semantic neighborhoods.

9:59:59.000,9:59:59.000
So you get the fruits,

9:59:59.000,9:59:59.000
the body parts,

9:59:59.000,9:59:59.000
the computer parts,

9:59:59.000,9:59:59.000
the scientific terms

9:59:59.000,9:59:59.000
and so on.

9:59:59.000,9:59:59.000
The algorithm also identifies[br]the reorganized concepts in a hierarchy.

9:59:59.000,9:59:59.000
So for instance,

9:59:59.000,9:59:59.000
you can see that the scientific terms[br]break down into two subcategories

9:59:59.000,9:59:59.000
of the astronomic and the physic terms.

9:59:59.000,9:59:59.000
And then their are very fine things.

9:59:59.000,9:59:59.000
For instance,

9:59:59.000,9:59:59.000
the word astronomy,

9:59:59.000,9:59:59.000
which seems a bit bizarre where it is,

9:59:59.000,9:59:59.000
is actually exactly where it should be,

9:59:59.000,9:59:59.000
between what it is --

9:59:59.000,9:59:59.000
an actual science --

9:59:59.000,9:59:59.000
and between what it describes --

9:59:59.000,9:59:59.000
the astronomical terms.

9:59:59.000,9:59:59.000
And we could go on and on with this.

9:59:59.000,9:59:59.000
Actually if you stare at this for awhile

9:59:59.000,9:59:59.000
and you just build random trajectories,

9:59:59.000,9:59:59.000
you will see that is feels well --

9:59:59.000,9:59:59.000
actually it feels a bit like doing poetry.

9:59:59.000,9:59:59.000
And this is because in way,

9:59:59.000,9:59:59.000
walking in this space[br]is like walking in the mind.

9:59:59.000,9:59:59.000
And last thing is that this algorithm[br]also identifies what are our intuitions,

9:59:59.000,9:59:59.000
of which words should lead[br]in the neighborhood of introspection.

9:59:59.000,9:59:59.000
So for instance,

9:59:59.000,9:59:59.000
words such as Self, Guilt,[br]Reason, Emotion,

9:59:59.000,9:59:59.000
are very close to introspection,

9:59:59.000,9:59:59.000
but other words,

9:59:59.000,9:59:59.000
such as Red, Football, Candle, Banana,

9:59:59.000,9:59:59.000
are just very far away.

9:59:59.000,9:59:59.000
And so once we've built this space,

9:59:59.000,9:59:59.000
the question of the history[br]of introspection,

9:59:59.000,9:59:59.000
or of the history of any concept,

9:59:59.000,9:59:59.000
which before could seem abstract[br]and somehow vague,

9:59:59.000,9:59:59.000
becomes concrete --

9:59:59.000,9:59:59.000
becomes amenable to quantitative science.

9:59:59.000,9:59:59.000
All that we have to do is take the books,

9:59:59.000,9:59:59.000
we digitize them

9:59:59.000,9:59:59.000
and we take this stream[br]of words as a trajectory

9:59:59.000,9:59:59.000
and project them into this space,

9:59:59.000,9:59:59.000
and then we ask whether this trajectory[br]spends significant time

9:59:59.000,9:59:59.000
circling closely to the concept[br]of introspection.

9:59:59.000,9:59:59.000
And with this,

9:59:59.000,9:59:59.000
we can analyze[br]the history of introspection

9:59:59.000,9:59:59.000
in the ancient Greek tradition,

9:59:59.000,9:59:59.000
for which we have the best[br]available written record.

9:59:59.000,9:59:59.000
So what we did is we took all the books --

9:59:59.000,9:59:59.000
we just ordered them by time --

9:59:59.000,9:59:59.000
for each book we take the words

9:59:59.000,9:59:59.000
and we project them to the space,

9:59:59.000,9:59:59.000
and then we ask for each word[br]how close it is to introspection,

9:59:59.000,9:59:59.000
and we just average that.

9:59:59.000,9:59:59.000
And then we understand[br]that as time goes on and on,

9:59:59.000,9:59:59.000
these books get closer,[br]and closer and closer

9:59:59.000,9:59:59.000
to the concept of introspection.

9:59:59.000,9:59:59.000
And this is exactly what happens[br]in the ancient Greek tradition.

9:59:59.000,9:59:59.000
So you can see that for the oldest books[br]in the Homeric tradition,

9:59:59.000,9:59:59.000
there is a small increase with books[br]getting closer to introspection,

9:59:59.000,9:59:59.000
but about four centuries before Christ,

9:59:59.000,9:59:59.000
this starts ramping up very rapidly

9:59:59.000,9:59:59.000
to an almost five-fold increase

9:59:59.000,9:59:59.000
of books getting closer,[br]and closer and closer

9:59:59.000,9:59:59.000
to the concept of introspection.

9:59:59.000,9:59:59.000
And one of the nice things about this

9:59:59.000,9:59:59.000
is that now we can ask

9:59:59.000,9:59:59.000
whether this is also true[br]in a different independent tradition.

9:59:59.000,9:59:59.000
So we just ran this same analysis[br]on the Judeo Christian tradition,

9:59:59.000,9:59:59.000
and we got virtually the same pattern.

9:59:59.000,9:59:59.000
Again you see a small increase[br]for the oldest books in the old testament,

9:59:59.000,9:59:59.000
and then it increases much more rapidly

9:59:59.000,9:59:59.000
in the new books of the new testament,

9:59:59.000,9:59:59.000
and then we get the peak of introspection

9:59:59.000,9:59:59.000
in the work Confessions[br]of Saint Augustine,

9:59:59.000,9:59:59.000
about four centuries after Christ.

9:59:59.000,9:59:59.000
And this was very important,

9:59:59.000,9:59:59.000
because Saint Augustine[br]had been recognized

9:59:59.000,9:59:59.000
by scholars, philologists, historians,

9:59:59.000,9:59:59.000
as one of the founders of introspection.

9:59:59.000,9:59:59.000
Actually, some believe him to be[br]the father of modern psychology.

9:59:59.000,9:59:59.000
So our algorithm --

9:59:59.000,9:59:59.000
which has the virtue[br]of being quantitative,

9:59:59.000,9:59:59.000
of being objective,

9:59:59.000,9:59:59.000
and of course of being extremely fast,

9:59:59.000,9:59:59.000
it just runs in a fraction of a second --

9:59:59.000,9:59:59.000
can capture some of the most[br]important conclusions

9:59:59.000,9:59:59.000
of this long tradition of investigation.

9:59:59.000,9:59:59.000
And this is in a way,[br]one of the beauties of science,

9:59:59.000,9:59:59.000
which is that now this idea can translated

9:59:59.000,9:59:59.000
and generalized to a whole[br]lot of different domains.

9:59:59.000,9:59:59.000
So in the same way that we asked[br]about the past of human conciousness,

9:59:59.000,9:59:59.000
maybe the most challenging question[br]we can pose to ourselves,

9:59:59.000,9:59:59.000
is whether this can tell us something[br]about the future of our unconciousness.

9:59:59.000,9:59:59.000
To put it more precisely,

9:59:59.000,9:59:59.000
whether the words we say today

9:59:59.000,9:59:59.000
can tell us something of where[br]our minds will be in a few days,

9:59:59.000,9:59:59.000
in a few months,

9:59:59.000,9:59:59.000
or a few years from now.

9:59:59.000,9:59:59.000
And in the way many of us[br]are now wearing censors

9:59:59.000,9:59:59.000
that detect our heart rate,

9:59:59.000,9:59:59.000
our respiration,

9:59:59.000,9:59:59.000
our genes,

9:59:59.000,9:59:59.000
on the hopes that this may[br]help us prevent diseases,

9:59:59.000,9:59:59.000
we can ask whether monitoring[br]and analyzing the words we speak --

9:59:59.000,9:59:59.000
we tweet,

9:59:59.000,9:59:59.000
we email,

9:59:59.000,9:59:59.000
we write --

9:59:59.000,9:59:59.000
can tell us ahead of time whether[br]something will go wrong with our minds.

9:59:59.000,9:59:59.000
And with Guillermo Cecci,

9:59:59.000,9:59:59.000
who has been my brother[br]in this adventure,

9:59:59.000,9:59:59.000
we took on this task.

9:59:59.000,9:59:59.000
And we did so by analyzing the recorded[br]speech for 44 young people

9:59:59.000,9:59:59.000
who were at a high risk[br]of developing schizophenia.

9:59:59.000,9:59:59.000
And so what we did is we[br]measured speech at day one

9:59:59.000,9:59:59.000
and then we asked

9:59:59.000,9:59:59.000
whether the properties[br]of the speech could predict --

9:59:59.000,9:59:59.000
within a window of almost three years --

9:59:59.000,9:59:59.000
the future development of psychosis.

9:59:59.000,9:59:59.000
But despite our hopes,

9:59:59.000,9:59:59.000
we got failure after failure.

9:59:59.000,9:59:59.000
There was just not enough[br]information in semantics

9:59:59.000,9:59:59.000
to predict the future[br]organization of the mind.

9:59:59.000,9:59:59.000
It was good enough

9:59:59.000,9:59:59.000
to distinguish between a group[br]of schizophrenics and a control group,

9:59:59.000,9:59:59.000
a bit like we had done[br]for the ancient texts,

9:59:59.000,9:59:59.000
but not to predict the future[br]onto the psychosis.

9:59:59.000,9:59:59.000
But then we realized

9:59:59.000,9:59:59.000
that maybe the most important thing[br]was not so much what they were saying

9:59:59.000,9:59:59.000
but how they were saying it.

9:59:59.000,9:59:59.000
More specifically,

9:59:59.000,9:59:59.000
it was not in which semantic[br]neighborhoods the words were,

9:59:59.000,9:59:59.000
but how far and fast they jumped[br]from one semantic neighborhood to another.

9:59:59.000,9:59:59.000
And so we came up with this measure,

9:59:59.000,9:59:59.000
which we termed Semantic Coherence,

9:59:59.000,9:59:59.000
which essentially measures

9:59:59.000,9:59:59.000
the persistence of speech[br]within one semantic topic,

9:59:59.000,9:59:59.000
within one semantic category.

9:59:59.000,9:59:59.000
And it turned out to be

9:59:59.000,9:59:59.000
that for this group of 44 people,

9:59:59.000,9:59:59.000
the algorithm based on semantic cohernece

9:59:59.000,9:59:59.000
could predict with 100 percent accuracy

9:59:59.000,9:59:59.000
who developed psychosis and who will not.

9:59:59.000,9:59:59.000
And this was something[br]that could not be achieved --

9:59:59.000,9:59:59.000
not even close --

9:59:59.000,9:59:59.000
with all the other[br]existing clinical measures.

9:59:59.000,9:59:59.000
And I remember vividly[br]while I was working on this,

9:59:59.000,9:59:59.000
I was sitting on my computer

9:59:59.000,9:59:59.000
and I saw a bunch of tweets by Polo.

9:59:59.000,9:59:59.000
Polo has been my first student[br]back in Buenos Aires

9:59:59.000,9:59:59.000
and at the time he was living in New York.

9:59:59.000,9:59:59.000
And there was something in this tweet --

9:59:59.000,9:59:59.000
I could not tell exactly what[br]because nothing was said explicitly --

9:59:59.000,9:59:59.000
but I got this strong hunch,

9:59:59.000,9:59:59.000
this strong intuition[br]that something was going wrong.

9:59:59.000,9:59:59.000
So I picked up the phone[br]and I called Polo,

9:59:59.000,9:59:59.000
and he was not feeling well.

9:59:59.000,9:59:59.000
And this simple fact that reading[br]in between the lines

9:59:59.000,9:59:59.000
I could sense through words[br]his feelings,

9:59:59.000,9:59:59.000
was a simple but very[br]effective way to help.

9:59:59.000,9:59:59.000
What I tell you today

9:59:59.000,9:59:59.000
is that we're getting[br]close to understanding

9:59:59.000,9:59:59.000
how we can convert this intuition[br]that we all have,

9:59:59.000,9:59:59.000
that we all share,

9:59:59.000,9:59:59.000
into an algorithm.

9:59:59.000,9:59:59.000
And in doing so,

9:59:59.000,9:59:59.000
we may be seeing in the future[br]a very different form of mental health,

9:59:59.000,9:59:59.000
based on objective, quantitative[br]and automated analysis

9:59:59.000,9:59:59.000
of the words we write,

9:59:59.000,9:59:59.000
of the words we say.

9:59:59.000,9:59:59.000
Gracias.

9:59:59.000,9:59:59.000
(Applause)