(whooshing and beeping tones)
(cheerful piano and string music)
- [Man] We are the paradoxical ape,
bipedal, naked, large-brained.
Long the master of fire, tools, and language,
but still trying to understand ourselves.
Aware that death is inevitable,
yet filled with optimism.
We grow up slowly.
We hand down knowledge.
We empathize and deceive.
We shape the future from our shared understanding
of the past.
CARTA brings together experts from diverse disciplines,
to exchange insights on who we are and how we got here,
an exploration made possible by the generosity of humans,
like you. (uplifting orchestra music)
(upbeat electronic music)
- I like to start with this very, kind of,
self-flattering question of:
How do we get so smart? (audience chuckles)
How are we humans able to think about
all of the complex and sophisticated things
that we think about?
How do we invent them?
And specifically, there's a puzzle
because, ultimately, we're physical creatures.
And we get only physical information from the world.
So we get photons in our eyes.
We get pressure waves in our ears.
We're subject to gravity,
and we bend our toes and flex our knees
to try to defy gravity and stay upright.
And we can push on things and exert pressure on the world.
And that somehow, through this super-physical interaction,
we end up with really fancy ideas.
Like, we think about goals and principles
and truth and justice.
We invent ideas like time travel and imaginary numbers.
How do we do that?
How does that set of physical interactions
and brains that are evolved
for these basic physical interactions,
how do they create this wonderful, abstract world of ideas?
And these abstract ideas are the things
that actually make being human so much fun.
So if you go to a dinner party,
and the only things you talk about
are physical, concrete things.
Like if all you can say is, "Boy, this podium is wooden
(knocks on podium) "and solid."
You're not gonna get invited back to that dinner party.
(audience chuckles) The things that we talk about,
the things that we obsess about, all day long,
are these abstract things.
How do our minds create these?
Now, this is a problem that has vexed scholars
for centuries.
Plato thought about it, so he thought about:
How would you teach someone an abstract idea, like virtue?
And he ends up concluding that it's impossible.
And we can't learn these things, so we must recollect them
from past incarnations of our souls.
Darwin, actually, also ran into this.
So Alfred Wallace, the co-originator
of the Theory of Evolution with Darwin,
gave up on the Theory of Evolution
because he got so vexed by this idea
of how brains that evolved for physical interaction,
how natural selection could have created
brains that then invent symphonies or play chess
or do any of the kinds of complex things that we do.
And Darwin tried to intervene, writing to Wallace,
"I hope you have not murdered too completely
"your own and my child."
Don't throw the baby out with bathwater.
We can save this evolution thing.
So how do we actually create these abstract ideas?
I'm gonna give you one, specific example,
and that is how we think about time.
Now, I do a lotta work on time.
I'm not the only one obsessed with time.
The work "time" is actually the most frequent noun
in English.
And that's kind of interesting because,
of course, we can't see time.
We can't touch time.
We can't smell time.
We can't taste time.
It's abstract.
But at the same time,
it creates the very basis
of our experience.
You can't experience anything outside of time.
So how do we conceptualize this abstract entity?
I'll take it one step further and ask:
How do we think about something like time travel?
How do we invent that idea?
Of course, it's not through physical experience
of your own, with time travel.
It's not because you actually traveled
to some other time and came back,
and now you can recollect that idea.
So here's a story
of how we might come up with an idea like time travel.
In lots of languages, we talk about time,
using spatial metaphors.
So we'll say things like,
"We're approaching the holidays"
or "We're coming up on Christmas."
"We're coming up on the deadline."
Well, if we're coming up on the holidays,
time is a path on which I'm traveling.
I'm traveling from the past to the future.
Once you have that analogy in place, that metaphor,
that time is a path that you can travel,
well, a path you can travel in whatever direction you want
and whatever speed you want.
So once you set that analogy,
you can now extend it
and think about something that goes beyond
what's possible in your physical experience.
You've invented the idea of time travel,
just by extending this little analogy.
There are a couple of ingredients to that story.
One is, you have to be able to make an analogy
between physical experience and something more abstract.
But also, something has to encourage you,
invite you to make that analogy.
Something has to say, "Well, why don't you try
"thinking about moving in time, like moving in space?"
And then, you can go beyond that.
How do we know that any part of this story
that I just told you is true,
that people actually do these kinds of extensions.
Let me give you a couple of examples.
In English, we actually have two, kind of opposing ways
of talking about time.
One talks about ourselves as moving
from the past to the future.
We call this the "ego-moving" metaphor.
And we say things like, "We're approaching the deadline."
The other one goes in the opposite direction.
We're stationary, and time is moving past us,
like a train or a river.
We call this the "time-moving" metaphor.
And so, you might say something like,
"The deadline is approaching."
Now, in a strict, physical sense,
if I'm approaching the deadline
or the deadline is approaching me,
those are the same.
If time is really a uni-directional, one-dimensional entity,
it doesn't actually matter which one of us is moving.
But in space, it matters.
So if I'm moving towards you,
or you're moving towards me,
those two things are different
because there's a fixed ground against which we're moving.
So we can actually tell the difference
of which one is happening.
How do we know if people really think about
"I'm approaching the deadline" as being different
from "The deadline is approaching"?
Do people really take these spatial metaphors seriously?
Here's one hint.
Suppose I ask you: "Next Wednesday's meeting
"has been moved forward two days.
"What day is the meeting, now that it's been rescheduled?"
(audience murmurs) Who thinks Monday?
Who thinks Friday?
Okay, it's about normal.
So if you're thinking of time moving towards you,
then moving the meeting forward
is moving the meeting in the direction of motion of time,
from Wednesday to Monday.
But if you think of yourself as moving through time,
then moving the meeting forward is
moving the meeting in your direction of motion,
from Wednesday to Friday.
And we can actually get people to imagine
motion in space.
So, for example, we'd say, "Imagine how you'd maneuver
"the chair to the X."
And you either have to imagine yourself scooting
in a chair, somewhere.
Or you imagine pulling a rope to bring a chair to you.
So in one case, you're imagining yourself moving.
In the other case, something is coming towards you.
And after people have imagined one or the other,
we slip in the seemingly unrelated question about time.
We say, "Next Wednesday's meeting has been
"moved forward two days.
"What day is the meeting?"
And what we find is, people who have been imagining
themselves moving forward through space
will say the meeting is now on Friday.
People who have been imagining something coming towards them
will say the meeting is now on Monday.
Course, they don't know that they're being influenced
by this imagination exercise that we gave them.
But what it's telling us is, people are actively using
the spatial image that they created to think about time.
Actually, these two scenarios in time
are psychologically different from them.
Now, the other thing about how we think about time
is that it differs from culture to culture.
So humans haven't invented just one way
of thinking about time.
But we invented many, many different ways.
Let me give you just a few examples.
So in English, of course, we read and write
from left to right.
And it's natural to then organize all kinds of things
from left to right.
So here, I'm showing you pictures of my grandfather
at different ages.
And if I gave you this set of cards, shuffled them,
and said, "Please lay them out in a correct order,"
chances are you would lay them out exactly like this,
from left to right.
We consider this to be the correct order,
the correct arrangement.
But people who read and write from right to left,
for example, people who read Arabic or Hebrew,
will organize these cards from right to left.
So for them, the direction of time
goes in the opposite direction.
And just to give you an intuition for this,
here's a logo for a nutritional supplement for kids.
And you can read this logo very easily,
and you can see what it does for your child.
When they tried using this in Arabic-speaking countries,
they ran into some problems (audience chuckles)
because if you read the logo from right to left,
it becomes quite problematic and confusing,
what it does for your child.
Now, so far, I've given you examples
of how time can travel with respect to the body,
either left to right or right to left.
But it can also travel not with respect to the body at all.
So here's an example.
This is an aboriginal community in Australia
that I had a chance to work with.
They live on the edge of Cape York.
They're the Kuuk Thaayore people.
And what's interesting about languages like Kuuk Thaayore
is they don't use words like "left" and "right."
Instead, they primarily rely on words like,
"north," "south," "east," and "west,"
cardinal direction terms.
And when I say they primarily rely
on cardinal direction terms,
I really mean that at all scales.
So even for body parts, you would say,
"There's an ant on your southwest leg"
or "Move your cup to the north/northeast a little bit,"
(cup taps on podium) things like that.
Even the way you say "hello," in Kuuk Thaayore
is to say, "Which way are you heading?"
And the answer should be something like,
"North/northwest, in the far distance.
"How about you?"
So imagine, as you walk around your day, everyone you greet,
you have to report your heading direction.
(audience chuckles) That would get you oriented
really quickly, right?
Because, literally, you could not get past "hello"
without knowing which way is which.
And let's just establish that we don't think like this.
Everyone close your eyes for a second.
And I can see you, so I can tell whether or not
you've closed your eyes.
Point southeast. (audience chuckles)
All right, you can open your eyes.
I see points in every possible direction.
(audience laughs) At least,
some of you are right. (audience laughs)
That's good.
So people who speak languages like Kuuk Thaayore
actually stay oriented really well.
They can point southeast without hesitation.
Even young children can do that.
But I also wondered: How do they think about time?
So if they don't think about left and right,
with respect to space, how do they lay out time?
So remember, if I give you this task,
I give you a bunch of cards to lay out.
What would they do?
So here's an example.
This is one participant.
They're sitting, facing south.
And this is a bunch of different card sets
they've laid out.
And what they've done is go from left to right
in each case.
Here's another participant.
I'm sorry; this is the same participant
on a different day, sitting facing north.
And they've laid everything out, now, from right to left.
Here's a different person, sitting, facing east.
And they've laid everything out,
coming towards the body.
What's the pattern?
It's the sun, from east to west.
So for them, time is locked on the landscape.
It doesn't stay locked on the body.
So for me, as an English speaker,
if I'm facing this way, then time goes this way.
And if I'm facing this way, then time goes this way.
Very egocentric of me to make the dimension of time
chase me around, every time I turn my body.
Instead, for the Kuuk Thaayore,
time always goes in the same direction,
with respect to the landscape,
regardless of which way their body is facing.
And this isn't the only way that time can flow,
according to the landscape.
So, for example, a work by Rafael Nunez,
here at UCSD, shows that time doesn't even have
to go in a straight line.
So, for example, for the Yupno of Papua, New Guinea,
time flows into the village at one angle.
And then, once it hits the village,
it takes a turn and flows out at a different angle.
And this has to do with
the mouth and the source of the Yupno River,
which are important geographical locations.
So people around the world have imagined
all kinds of ways to organize this very basic dimension,
whether it goes left to right, right to left.
There are vertical organizations,
organizations that go on the landscape,
in all kinds of different ways.
There's a really rich variety that humans have invented,
around the world.
Now, you could ask: How deeply rooted is this
imagined time, in our idea of space?
So if you were to disable the part of the brain
that processes a particular part of space,
would that also disrupt our ability to imagine
that part of time?
And we actually had a chance to test this idea,
by looking at patients who've suffered strokes
in their right parietal lobe.
So here, I'm showing you the brain of Federico Fellini,
after he suffered a stroke in his right parietal lobe.
And this kind of stroke often results in neglect,
on the opposite side of the stroke.
If you have left neglect, in everyday life,
you might not notice food on the left side of your plate.
You might only eat the food on the ride side of your plate,
even though you're still hungry.
You might only put makeup on one side of your face
or shave one side of your face.
You might only read words on one side of the page.
People with neglect seem to not notice,
not pay attention to, things on the left side
of space, for them.
This member of Kiss doesn't have neglect
as far as I know.
But this is how he would do his makeup,
if he would. (audience chuckles)
So we wondered: How would patients,
who neglect the left side of space, think about time?
So we told patients about a guy, David,
fictional guy, David, who likes doing some things
10 years ago and will like doing different things,
10 years from now.
So 10 years ago, he liked strawberries,
but 10 years from now, he will like cherries.
And they just had to remember these facts.
And we had a couple of control groups.
We had healthy controls
and also patients who'd had a stroke,
but didn't show signs of neglect.
So let me show you data from the two control groups, first.
So the solid bars, here, show you
the items that people got right.
And everything to the right of the center
is things to do with the future.
Everything to the left of the center
is things to do with the past.
The shaded areas are where people made mistakes.
Now, of course, both groups made some mistakes,
but the mistakes are symmetrical,
around the past and the future.
Here's what the neglect patients look like.
They were heavily shifted to the right.
They weren't able to recognize, correctly,
things that had do with the past,
with the left side of the mental timeline.
And instead, they misattributed a whole lot of things
to the right.
So when you damage the part of the brain
that's responsible for representing the left side of space,
you also damage the imagined left,
the time that you imagine on the left side of your body.
Now, I've been giving a lot of examples about
how we imagine time and space
and how metaphors and cultural artifacts,
like reading and writing, invite us to
make different kinds of analogies.
But, of course, these ideas go far beyond
how we think about time.
Because metaphors are ubiquitous in our experience.
Just about anything that's complex or interesting
is at least partially imagined.
And the way we talk about these complex,
interesting things is suffused with metaphor.
So if you're talking about a relationship problem,
you might say, "Well, we're spinning our wheels.
"Our relationship is off track."
If we're talking about the economy, you might say,
"We need to jump-start the economy."
And the idea is that a quick stimulus
is what the economy needs, to get going, again.
Or you might say that we need "prop up the economy."
And then, you're using
a different set of physical metaphors,
to think about what needs to happen.
When we talk theories or ideas, we could talk about
"poking holes" or "warming up to ideas."
With social issues, we talk about
immigrants as "seeping into the country,"
as if they're some kind of nefarious substance
or crime as "preying" or "infecting" our neighborhoods.
And these metaphors have psychological weight.
So, for example, in our lab, we've looked at
how people want to approach a crime problem in a city.
If you tell them that "Crime is a beast,
"plaguing their city" or "preying on their city,"
as opposed to "Crime is a virus."
If you tell them, "Crime is a beast,"
they want to do the kinds of things
you would normally do to contain a beast.
So they want harsher enforcement measures.
If you tell them, "Crime is a virus,"
they want to take a more epidemiological approach.
They wanna diagnose the problem,
maybe inoculate the population,
do things that are more reform-oriented.
So these metaphors have real, psychological weight.
So coming back to this question of: How do we get so smart?
My answer would be that our brains are masters
at doing dynamic, opportunistic bricolage.
They recycle and reuse machinery that has evolved
for simple, perceptual motor tasks.
They recycle and reuse the knowledge that we acquire
through physical experience.
But also, language is an incredibly powerful tool
that invites us to conjure up those ideas
and recombine them in all kinds of novel ways
because language supplies us with a large stock
of units, but an infinite ability to recombine them.
So I can, right now, take a bunch of words,
put them in a new configuration
and invite you to imagine something
you've never imagined before.
So I could say, "Imagine a circle of hedgehogs
"dancing the polka on top of a crepe
"that is traveling through time,
"from paleolithic times to now,
"to puzzle us about how they are able
"to make such fine, thin pastry, back then."
(audience laughs) Now, if everything
has gone relatively well in your life, so far,
you haven't had that thought before, right?
(audience laughs) And so, you're welcome.
That is through the power of language,
we can conjure up all kinds of ideas,
an infinite set of new ideas,
by recombining things from our physical experience
and from other abstract ideas we've built in the past.
Thank you very much. (audience applause)
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