Translator: Ilze Garda Reviewer: Denise RQ
Hi!
Do you know how the brain works?
(Laughter)
Neither do I, but it is my quest to study it.
When people hear that I study the brain, the first thing they ask me is,
"Is it true that we only use 10% of our brain?"
See, according to myth,
there is 90% of brain that we are not using,
just waiting to be used.
So, is it so?
My answer will be a little bit disappointing:
we use all our brain, all 100% of it.
And if your were to lose 90% of your brain,
it would be noticeable.
(Laughter)
But let's replace that fallacy with some real numbers.
Only 10% of the inputs into the brain arise directly from our senses:
from our eyes seeing, from our ears hearing.
The rest is what I like to call "brain chatter".
It's stuff that is going on that is removed from the outside world,
but rather is shaped by connections and computations,
different areas in the brain that are talking to each other.
I study this 90% of brain chatter,
and my hope is to understand better how we perceive, how we attend,
basically, how we experience the world.
Take a look at this image here.
Three Pac-Mans is all that is there, there are no lines connecting the Pac-Mans
and no surface laid on top of them.
Yet, we all can't help but to see a triangle, an object that isn't there.
How about this face here? It's a bit strange, it's a morph.
(Laughter)
It's a morph, it's 50% Obama and 50% Bush.
We can call him Bubama.
(Laughter)
Take a look at Bubama.
I'm going to now transition to Obama as you are used to seeing him,
and I'm going to ask you to, please, take a look at him,
stare at him as long as I allow you to,
because in a few moments, after we're done looking at Obama,
I will bring Bubama back, and this time he's going to look a little different.
So, an extra moment to stare at Obama.
Here you go.
(Laughter)
It's an identical picture of Bubama,
but your brain now has a different history.
It has seen what Obama looks like, and now Bubama looks a lot like Bush.
So 90% brain chatter is what makes us see
objects that are not there,
it's what makes us see an identical face differently the second time around.
Brain chatter is also responsible for a very important ability we have.
It's our megafilter
without which we could not function, and it probably has to do
with the reason that TED talks are getting shorter and shorter as years go by.
(Laughter)
It's attention.
Humans have an incredible ability
to only select things that are relevant to what they need.
That is what we call attention.
Imagine you're at the fairground,
a lot is going on, there are noises, lights, kids,
they're screaming in terror from the rides
or laughing with joy and, of course, jumping crazily from the sugar rush.
It's complete overstimulation,
but the amazing fact is we are able to figure out
where our attention should go.
If I take my 5-year-old to this fairground and put her
in front of a sweet cotton candy treat,
that is what she will devote her attention to.
(Laughter)
The rest of the world, the bustle, the noise, the lights reach her senses,
but they're practically absent from her experience.
She's one with the cotton candy.
(Laughter)
So how does attention work?
How does the brain dim out everything else except for that cotton candy?
We can answer this question by looking at brain dynamics.
We could also answer this question by measuring behavior,
and the two, of course, are related.
When we pay attention to one thing,
different parts of the brain that are processing it are communicating.
So, in the case of cotton candy,
we have areas in the brain that identify its pink color,
other areas in the brain that identify its form,
and, of course, areas that store memories of how great it tastes.
All those areas are engaged in vigorous communication and brain chatter.
The rest of the bustle is unattended,
and so there is far less brain chatter associated with it.
Now, in behavior,
even when we're focusing on one thing,
it turns out that attention isn't working constantly at the same level.
So we're looking at the cotton candy, we're experiencing it continuously,
[and] in fact, if I were to measure behavior carefully,
what actually is happening is that we have better moments and worse moments.
There are moments where we can see the cotton candy better with our brains,
and moments where we are barely seeing it.
These transitions between those better moments and worse moments
occur around eight times a second.
This again sounds a bit strange probably
because, as I said, we all experience our environment continuously.
You might wonder,
"Are there any conditions under which we could experience
these transitions, this rhythm that occurs eight times a second?"
There is a group of researchers in Toulouse, France, that figured out
that there are some configurations in which we can all experience
the rhythm that shapes our experience.
We can see the rhythm that shapes our experience.
So take a look at this wheel behind me.
Focus on the blue dot.
At some point, it will start moving, and I would like to ask you
to track the dot as it's revolving around the wheel.
What do you see?
Most of you should perceive
something strange going on at the center of the wheel,
something that is flickering, something that is rhythmic.
So these kinds of stimuli allow us momentarily,
or under these very special conditions,
to experience this rhythm.
Let's go back to the fairground.
Our reality is much more complex than paying attention to one thing.
There are many things that are occurring in our environment that require attention.
A question that interested me was,
"Is this rhythm of attention a hard-wired feature?
Is that all we have? Eight good moments a second?
Or, is attention and the brain a flexible tool that adjusts
depending on needs of our environment?"
If I want to go to the funfair with both of my girls,
I want both of them to go on their favorite ride at the same time,
am I going to be able to pay attention to both of them
just as well as if I were there with one child?
I found a way to test that in the lab.
I had people view two things on the screen and monitor them
for a subtle change in one of them.
They had to distribute their attention.
What I found
was that the same rhythm that is key in paying attention to one object
was now distributed over these two locations.
Not only that, it was alternating
between the two regions, between the two objects.
It's a little bit like a seesaw if you will.
So back to the fairground again.
If I am there with both of my girls,
then paying attention to both of them, in essence,
means I'm going to be alternating between the two different rides
to pay attention to them.
The same rhythm that plays a role in paying attention to one object
is the rhythm that also governs attention to more complex scenes,
two objects, and even three objects.
Another surprising fact that I found was that when I looked
at all the individuals that came to my experiments,
the rhythm was rather consistent.
Attention is a hard-wired and consistent feature,
and seeing this consistency made me realize that perhaps it's similar
to other exploration behaviors in the animal kingdom.
It turns out that also rodents whisk and sniff at that rhythm.
Primates move their eyes at that rhythm.
So we're looking at a rather consistent phenomena,
and in this context,
you could think of attention as an exploration behavior in humans.
My research comes with some good news and some bad news.
The bad news is when you are driving your car
and conducting a conversation at the same time,
your resources are limited, and they are alternating
between the conversation, the road, the conversation, the road,
that is happening eight times a second.
It doesn't really matter if you're talking through a headset, a speaker phone,
or if you're holding the phone in your hand.
When you're paying attention to the conversation,
you're not paying attention to the road.
The good news is that we might be able to use this discovery
that attention is a rhythm in the clinic.
There are many conditions
that are characterized by a deficit in attention:
ADD, affective disorders, stroke, just to name a few.
If the rhythm is a hard-wired feature of attention,
we might think of these disorders as, what I like to call, brain arrhythmia,
cases where the intact rhythm of attention is disrupted.
Moreover, if indeed attention deficits stem from brain arrhythmia,
we need to think about attention pacemakers.
Perhaps, we could regulate the correct rhythms.
Think about it as if it's a rhythmic gymnastic class for the brain.
So I ask you now to imagine a stroke patient,
in a word, wearing headphones that are emitting rhythmic clicks,
and those rhythmic clicks are teaching the brain
what a correct rhythm of attention is.
We could do even better if we use shutter glasses
that are omitting and exposing the world rhythmically to our patient.
We could make sure
that the sensory input is making it to our senses at the appropriate rhythm.
By studying attention, I was able to discover
that what we called brain chatter at first
is not quite a random brain chatter, but rather a meaningful conversation.
If 90% of brain chatter
actually hides within it meaningful conversations,
we have a quest when we approach the study of the brain.
Our quest is to listen to brain chatter,
to decode the underlying structures that are there,
and by doing that, we can start a frontier
in understanding ourselves and understanding how the brain works.
Thank you.
(Applause)