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TED2015

David Eagleman: Can we create new senses for humans?

March 17, 2015

As humans, we can perceive less than a ten-trillionth of all light waves. “Our experience of reality,” says neuroscientist David Eagleman, “is constrained by our biology.” He wants to change that. His research into our brain processes has led him to create new interfaces -- such as a sensory vest -- to take in previously unseen information about the world around us.

David Eagleman - Neuroscientist
David Eagleman decodes the mysteries of the tangled web of neurons and electricity that make our minds tick -- and also make us human. Full bio

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Double-click the English subtitles below to play the video.
We are built out of very small stuff,
00:12
and we are embedded in
a very large cosmos,
00:17
and the fact is that we are not
very good at understanding reality
00:19
at either of those scales,
00:24
and that's because our brains
00:25
haven't evolved to understand
the world at that scale.
00:27
Instead, we're trapped on this
very thin slice of perception
00:31
right in the middle.
00:36
But it gets strange, because even at
that slice of reality that we call home,
00:38
we're not seeing most
of the action that's going on.
00:43
So take the colors of our world.
00:45
This is light waves, electromagnetic
radiation that bounces off objects
00:49
and it hits specialized receptors
in the back of our eyes.
00:54
But we're not seeing
all the waves out there.
00:57
In fact, what we see
01:01
is less than a 10 trillionth
of what's out there.
01:02
So you have radio waves and microwaves
01:06
and X-rays and gamma rays
passing through your body right now
01:10
and you're completely unaware of it,
01:13
because you don't come with
the proper biological receptors
01:16
for picking it up.
01:19
There are thousands
of cell phone conversations
01:21
passing through you right now,
01:24
and you're utterly blind to it.
01:25
Now, it's not that these things
are inherently unseeable.
01:27
Snakes include some infrared
in their reality,
01:31
and honeybees include ultraviolet
in their view of the world,
01:36
and of course we build machines
in the dashboards of our cars
01:40
to pick up on signals
in the radio frequency range,
01:43
and we built machines in hospitals
to pick up on the X-ray range.
01:46
But you can't sense
any of those by yourself,
01:50
at least not yet,
01:53
because you don't come equipped
with the proper sensors.
01:55
Now, what this means is that
our experience of reality
01:59
is constrained by our biology,
02:03
and that goes against
the common sense notion
02:07
that our eyes and our ears
and our fingertips
02:09
are just picking up
the objective reality that's out there.
02:11
Instead, our brains are sampling
just a little bit of the world.
02:16
Now, across the animal kingdom,
02:21
different animals pick up
on different parts of reality.
02:23
So in the blind
and deaf world of the tick,
02:27
the important signals
are temperature and butyric acid;
02:30
in the world of the black ghost knifefish,
02:34
its sensory world is lavishly colored
by electrical fields;
02:37
and for the echolocating bat,
02:42
its reality is constructed
out of air compression waves.
02:44
That's the slice of their ecosystem
that they can pick up on,
02:48
and we have a word for this in science.
02:53
It's called the umwelt,
02:55
which is the German word
for the surrounding world.
02:56
Now, presumably, every animal assumes
03:00
that its umwelt is the entire
objective reality out there,
03:03
because why would you ever stop to imagine
03:07
that there's something beyond
what we can sense.
03:10
Instead, what we all do
is we accept reality
03:13
as it's presented to us.
03:15
Let's do a consciousness-raiser on this.
03:19
Imagine that you are a bloodhound dog.
03:21
Your whole world is about smelling.
03:24
You've got a long snout that has
200 million scent receptors in it,
03:26
and you have wet nostrils
that attract and trap scent molecules,
03:31
and your nostrils even have slits
so you can take big nosefuls of air.
03:35
Everything is about smell for you.
03:39
So one day, you stop in your tracks
with a revelation.
03:43
You look at your human owner
and you think,
03:47
"What is it like to have the pitiful,
impoverished nose of a human?
03:50
(Laughter)
03:55
What is it like when you take
a feeble little noseful of air?
03:56
How can you not know that there's
a cat 100 yards away,
04:00
or that your neighbor was on
this very spot six hours ago?"
04:04
(Laughter)
04:07
So because we're humans,
04:10
we've never experienced
that world of smell,
04:12
so we don't miss it,
04:15
because we are firmly settled
into our umwelt.
04:17
But the question is,
do we have to be stuck there?
04:21
So as a neuroscientist, I'm interested
in the way that technology
04:26
might expand our umwelt,
04:30
and how that's going to change
the experience of being human.
04:33
So we already know that we can marry
our technology to our biology,
04:38
because there are hundreds of thousands
of people walking around
04:41
with artificial hearing
and artificial vision.
04:45
So the way this works is, you take
a microphone and you digitize the signal,
04:48
and you put an electrode strip
directly into the inner ear.
04:53
Or, with the retinal implant,
you take a camera
04:57
and you digitize the signal,
and then you plug an electrode grid
04:59
directly into the optic nerve.
05:02
And as recently as 15 years ago,
05:05
there were a lot of scientists who thought
these technologies wouldn't work.
05:09
Why? It's because these technologies
speak the language of Silicon Valley,
05:13
and it's not exactly the same dialect
as our natural biological sense organs.
05:18
But the fact is that it works;
05:24
the brain figures out
how to use the signals just fine.
05:26
Now, how do we understand that?
05:31
Well, here's the big secret:
05:33
Your brain is not hearing
or seeing any of this.
05:35
Your brain is locked in a vault of silence
and darkness inside your skull.
05:40
All it ever sees are
electrochemical signals
05:47
that come in along different data cables,
05:50
and this is all it has to work with,
and nothing more.
05:53
Now, amazingly,
05:58
the brain is really good
at taking in these signals
06:00
and extracting patterns
and assigning meaning,
06:03
so that it takes this inner cosmos
and puts together a story
06:07
of this, your subjective world.
06:11
But here's the key point:
06:15
Your brain doesn't know,
and it doesn't care,
06:17
where it gets the data from.
06:21
Whatever information comes in,
it just figures out what to do with it.
06:24
And this is a very efficient
kind of machine.
06:29
It's essentially a general purpose
computing device,
06:31
and it just takes in everything
06:35
and figures out
what it's going to do with it,
06:38
and that, I think, frees up Mother Nature
06:40
to tinker around with different
sorts of input channels.
06:44
So I call this the P.H.
model of evolution,
06:49
and I don't want to get
too technical here,
06:52
but P.H. stands for Potato Head,
06:54
and I use this name to emphasize
that all these sensors
06:57
that we know and love, like our eyes
and our ears and our fingertips,
07:01
these are merely peripheral
plug-and-play devices:
07:04
You stick them in, and you're good to go.
07:08
The brain figures out what to do
with the data that comes in.
07:11
And when you look across
the animal kingdom,
07:18
you find lots of peripheral devices.
07:20
So snakes have heat pits
with which to detect infrared,
07:22
and the ghost knifefish has
electroreceptors,
07:27
and the star-nosed mole has this appendage
07:30
with 22 fingers on it
07:32
with which it feels around and constructs
a 3D model of the world,
07:35
and many birds have magnetite
so they can orient
07:39
to the magnetic field of the planet.
07:43
So what this means is that
nature doesn't have to continually
07:45
redesign the brain.
07:49
Instead, with the principles
of brain operation established,
07:51
all nature has to worry about
is designing new peripherals.
07:56
Okay. So what this means is this:
08:01
The lesson that surfaces
08:03
is that there's nothing
really special or fundamental
08:06
about the biology that we
come to the table with.
08:09
It's just what we have inherited
08:12
from a complex road of evolution.
08:14
But it's not what we have to stick with,
08:17
and our best proof of principle of this
08:21
comes from what's called
sensory substitution.
08:23
And that refers to feeding
information into the brain
08:26
via unusual sensory channels,
08:29
and the brain just figures out
what to do with it.
08:32
Now, that might sound speculative,
08:35
but the first paper demonstrating this was
published in the journal Nature in 1969.
08:37
So a scientist named Paul Bach-y-Rita
08:43
put blind people
in a modified dental chair,
08:46
and he set up a video feed,
08:49
and he put something
in front of the camera,
08:51
and then you would feel that
08:53
poked into your back
with a grid of solenoids.
08:56
So if you wiggle a coffee cup
in front of the camera,
08:59
you're feeling that in your back,
09:01
and amazingly, blind people
got pretty good
09:04
at being able to determine
what was in front of the camera
09:07
just by feeling it
in the small of their back.
09:10
Now, there have been many
modern incarnations of this.
09:14
The sonic glasses take a video feed
right in front of you
09:18
and turn that into a sonic landscape,
09:21
so as things move around,
and get closer and farther,
09:24
it sounds like "Bzz, bzz, bzz."
09:26
It sounds like a cacophony,
09:28
but after several weeks, blind people
start getting pretty good
09:30
at understanding what's in front of them
09:34
just based on what they're hearing.
09:37
And it doesn't have to be
through the ears:
09:39
this system uses an electrotactile grid
on the forehead,
09:41
so whatever's in front of the video feed,
you're feeling it on your forehead.
09:45
Why the forehead? Because you're not
using it for much else.
09:48
The most modern incarnation
is called the brainport,
09:51
and this is a little electrogrid
that sits on your tongue,
09:55
and the video feed gets turned into
these little electrotactile signals,
09:59
and blind people get so good at using this
that they can throw a ball into a basket,
10:03
or they can navigate
complex obstacle courses.
10:10
They can come to see through their tongue.
10:15
Now, that sounds completely insane, right?
10:19
But remember, all vision ever is
10:21
is electrochemical signals
coursing around in your brain.
10:24
Your brain doesn't know
where the signals come from.
10:28
It just figures out what to do with them.
10:31
So my interest in my lab
is sensory substitution for the deaf,
10:34
and this is a project I've undertaken
10:40
with a graduate student
in my lab, Scott Novich,
10:43
who is spearheading this for his thesis.
10:46
And here is what we wanted to do:
10:48
we wanted to make it so that
sound from the world gets converted
10:50
in some way so that a deaf person
can understand what is being said.
10:54
And we wanted to do this, given the power
and ubiquity of portable computing,
10:59
we wanted to make sure that this
would run on cell phones and tablets,
11:03
and also we wanted
to make this a wearable,
11:08
something that you could wear
under your clothing.
11:10
So here's the concept.
11:13
So as I'm speaking, my sound
is getting captured by the tablet,
11:17
and then it's getting mapped onto a vest
that's covered in vibratory motors,
11:22
just like the motors in your cell phone.
11:27
So as I'm speaking,
11:31
the sound is getting translated
to a pattern of vibration on the vest.
11:33
Now, this is not just conceptual:
11:40
this tablet is transmitting Bluetooth,
and I'm wearing the vest right now.
11:41
So as I'm speaking -- (Applause) --
11:46
the sound is getting translated
into dynamic patterns of vibration.
11:49
I'm feeling the sonic world around me.
11:55
So, we've been testing this
with deaf people now,
12:01
and it turns out that after
just a little bit of time,
12:05
people can start feeling,
they can start understanding
12:08
the language of the vest.
12:12
So this is Jonathan. He's 37 years old.
He has a master's degree.
12:14
He was born profoundly deaf,
12:19
which means that there's a part
of his umwelt that's unavailable to him.
12:21
So we had Jonathan train with the vest
for four days, two hours a day,
12:26
and here he is on the fifth day.
12:30
Scott Novich: You.
12:33
David Eagleman: So Scott says a word,
Jonathan feels it on the vest,
12:35
and he writes it on the board.
12:39
SN: Where. Where.
12:42
DE: Jonathan is able to translate
this complicated pattern of vibrations
12:45
into an understanding
of what's being said.
12:49
SN: Touch. Touch.
12:52
DE: Now, he's not doing this --
12:56
(Applause) --
13:00
Jonathan is not doing this consciously,
because the patterns are too complicated,
13:07
but his brain is starting to unlock
the pattern that allows it to figure out
13:11
what the data mean,
13:17
and our expectation is that,
after wearing this for about three months,
13:19
he will have a direct
perceptual experience of hearing
13:23
in the same way that when a blind person
passes a finger over braille,
13:28
the meaning comes directly off the page
without any conscious intervention at all.
13:32
Now, this technology has the potential
to be a game-changer,
13:38
because the only other solution
for deafness is a cochlear implant,
13:42
and that requires an invasive surgery.
13:46
And this can be built for 40 times cheaper
than a cochlear implant,
13:49
which opens up this technology globally,
even for the poorest countries.
13:54
Now, we've been very encouraged
by our results with sensory substitution,
13:59
but what we've been thinking a lot about
is sensory addition.
14:04
How could we use a technology like this
to add a completely new kind of sense,
14:09
to expand the human umvelt?
14:14
For example, could we feed
real-time data from the Internet
14:17
directly into somebody's brain,
14:22
and can they develop a direct
perceptual experience?
14:23
So here's an experiment
we're doing in the lab.
14:27
A subject is feeling a real-time
streaming feed from the Net of data
14:30
for five seconds.
14:34
Then, two buttons appear,
and he has to make a choice.
14:36
He doesn't know what's going on.
14:39
He makes a choice,
and he gets feedback after one second.
14:40
Now, here's the thing:
14:43
The subject has no idea
what all the patterns mean,
14:44
but we're seeing if he gets better
at figuring out which button to press.
14:47
He doesn't know that what we're feeding
14:51
is real-time data from the stock market,
14:53
and he's making buy and sell decisions.
14:56
(Laughter)
14:58
And the feedback is telling him
whether he did the right thing or not.
15:01
And what we're seeing is,
can we expand the human umvelt
15:04
so that he comes to have,
after several weeks,
15:07
a direct perceptual experience
of the economic movements of the planet.
15:10
So we'll report on that later
to see how well this goes.
15:16
(Laughter)
15:19
Here's another thing we're doing:
15:22
During the talks this morning,
we've been automatically scraping Twitter
15:24
for the TED2015 hashtag,
15:29
and we've been doing
an automated sentiment analysis,
15:31
which means, are people using positive
words or negative words or neutral?
15:34
And while this has been going on,
15:38
I have been feeling this,
15:41
and so I am plugged in
to the aggregate emotion
15:44
of thousands of people in real time,
15:48
and that's a new kind of human experience,
because now I can know
15:52
how everyone's doing
and how much you're loving this.
15:56
(Laughter) (Applause)
15:59
It's a bigger experience
than a human can normally have.
16:06
We're also expanding the umvelt of pilots.
16:11
So in this case, the vest is streaming
nine different measures
16:14
from this quadcopter,
16:18
so pitch and yaw and roll
and orientation and heading,
16:20
and that improves
this pilot's ability to fly it.
16:23
It's essentially like he's extending
his skin up there, far away.
16:27
And that's just the beginning.
16:32
What we're envisioning is taking
a modern cockpit full of gauges
16:34
and instead of trying
to read the whole thing, you feel it.
16:40
We live in a world of information now,
16:44
and there is a difference
between accessing big data
16:47
and experiencing it.
16:51
So I think there's really no end
to the possibilities
16:54
on the horizon for human expansion.
16:57
Just imagine an astronaut
being able to feel
17:00
the overall health
of the International Space Station,
17:05
or, for that matter, having you feel
the invisible states of your own health,
17:08
like your blood sugar
and the state of your microbiome,
17:13
or having 360-degree vision
or seeing in infrared or ultraviolet.
17:17
So the key is this:
As we move into the future,
17:22
we're going to increasingly be able
to choose our own peripheral devices.
17:26
We no longer have to wait
for Mother Nature's sensory gifts
17:31
on her timescales,
17:35
but instead, like any good parent,
she's given us the tools that we need
17:37
to go out and define our own trajectory.
17:41
So the question now is,
17:45
how do you want to go out
and experience your universe?
17:47
Thank you.
17:52
(Applause)
17:54
Chris Anderson: Can you feel it?
DE: Yeah.
18:11
Actually, this was the first time
I felt applause on the vest.
18:13
It's nice. It's like a massage. (Laughter)
18:16
CA: Twitter's going crazy.
Twitter's going mad.
18:18
So that stock market experiment.
18:22
This could be the first experiment
that secures its funding forevermore,
18:24
right, if successful?
18:29
DE: Well, that's right, I wouldn't
have to write to NIH anymore.
18:31
CA: Well look, just to be
skeptical for a minute,
18:34
I mean, this is amazing,
but isn't most of the evidence so far
18:37
that sensory substitution works,
18:40
not necessarily
that sensory addition works?
18:42
I mean, isn't it possible that the
blind person can see through their tongue
18:44
because the visual cortex is still there,
ready to process,
18:48
and that that is needed as part of it?
18:53
DE: That's a great question.
We actually have no idea
18:55
what the theoretical limits are of what
kind of data the brain can take in.
18:58
The general story, though,
is that it's extraordinarily flexible.
19:02
So when a person goes blind,
what we used to call their visual cortex
19:05
gets taken over by other things,
by touch, by hearing, by vocabulary.
19:09
So what that tells us is that
the cortex is kind of a one-trick pony.
19:14
It just runs certain kinds
of computations on things.
19:18
And when we look around
at things like braille, for example,
19:20
people are getting information
through bumps on their fingers.
19:23
So I don't thing we have any reason
to think there's a theoretical limit
19:26
that we know the edge of.
19:30
CA: If this checks out,
you're going to be deluged.
19:33
There are so many
possible applications for this.
19:36
Are you ready for this? What are you most
excited about, the direction it might go?
19:39
DE: I mean, I think there's
a lot of applications here.
19:43
In terms of beyond sensory substitution,
the things I started mentioning
19:46
about astronauts on the space station,
they spend a lot of their time
19:49
monitoring things, and they could instead
just get what's going on,
19:53
because what this is really good for
is multidimensional data.
19:57
The key is this: Our visual systems
are good at detecting blobs and edges,
20:00
but they're really bad
at what our world has become,
20:05
which is screens
with lots and lots of data.
20:07
We have to crawl that
with our attentional systems.
20:10
So this is a way of just
feeling the state of something,
20:12
just like the way you know the state
of your body as you're standing around.
20:15
So I think heavy machinery, safety,
feeling the state of a factory,
20:18
of your equipment, that's one place
it'll go right away.
20:21
CA: David Eagleman, that was one
mind-blowing talk. Thank you very much.
20:24
DE: Thank you, Chris.
(Applause)
20:28

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David Eagleman - Neuroscientist
David Eagleman decodes the mysteries of the tangled web of neurons and electricity that make our minds tick -- and also make us human.

Why you should listen

As the creator of stacks of compelling research, books and now the 6-part PBS series The Brain, grey matter expert David Eagleman is our most visible evangelist for neuroscience. He has helmed ground-breaking studies on time perception, brain plasticity and neurolaw. His latest research explores technology that bypasses sensory impairment -- such as a smartphone-controlled vest that translates sound into patterns of vibration for the deaf.

Eagleman is also the author of Sum, an internationally bestselling short story collection speculating on life, death and what it means to be human. Translated into 28 languages, Sum has been turned into two separate operas at the Sydney Opera House and the Royal Opera House in London.

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