Jeff Hawkins: How brain science will change computing

207,998 views ・ 2007-05-23

TED


Please double-click on the English subtitles below to play the video.

00:25
I do two things:
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I design mobile computers and I study brains.
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Today's talk is about brains and -- (Audience member cheers)
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Yay! I have a brain fan out there.
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(Laughter)
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If I could have my first slide,
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you'll see the title of my talk and my two affiliations.
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So what I'm going to talk about is why we don't have a good brain theory,
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why it is important that we should develop one
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and what we can do about it.
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I'll try to do all that in 20 minutes.
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I have two affiliations.
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Most of you know me from my Palm and Handspring days,
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but I also run a nonprofit scientific research institute
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called the Redwood Neuroscience Institute in Menlo Park.
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We study theoretical neuroscience and how the neocortex works.
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I'm going to talk all about that.
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I have one slide on my other life, the computer life,
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and that's this slide here.
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These are some of the products I've worked on over the last 20 years,
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starting from the very original laptop
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to some of the first tablet computers
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and so on, ending up most recently with the Treo,
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and we're continuing to do this.
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I've done this because I believe mobile computing
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is the future of personal computing,
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and I'm trying to make the world a little bit better
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by working on these things.
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But this was, I admit, all an accident.
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I really didn't want to do any of these products.
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Very early in my career
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I decided I was not going to be in the computer industry.
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Before that, I just have to tell you
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about this picture of Graffiti I picked off the web the other day.
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I was looking for a picture for Graffiti that'll text input language.
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I found a website dedicated to teachers who want to make script-writing things
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across the top of their blackboard,
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and they had added Graffiti to it, and I'm sorry about that.
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(Laughter)
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So what happened was,
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when I was young and got out of engineering school at Cornell in '79,
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I went to work for Intel and was in the computer industry,
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and three months into that, I fell in love with something else.
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I said, "I made the wrong career choice here,"
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and I fell in love with brains.
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This is not a real brain.
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This is a picture of one, a line drawing.
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And I don't remember exactly how it happened,
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but I have one recollection, which was pretty strong in my mind.
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In September of 1979,
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Scientific American came out with a single-topic issue about the brain.
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It was one of their best issues ever.
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They talked about the neuron, development, disease, vision
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and all the things you might want to know about brains.
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It was really quite impressive.
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One might've had the impression we knew a lot about brains.
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But the last article in that issue was written by Francis Crick of DNA fame.
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Today is, I think, the 50th anniversary of the discovery of DNA.
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And he wrote a story basically saying, this is all well and good,
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but you know, we don't know diddly squat about brains,
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and no one has a clue how they work,
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so don't believe what anyone tells you.
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This is a quote from that article, he says:
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"What is conspicuously lacking" -- he's a very proper British gentleman --
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"What is conspicuously lacking is a broad framework of ideas
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in which to interpret these different approaches."
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I thought the word "framework" was great.
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He didn't say we didn't have a theory.
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He says we don't even know how to begin to think about it.
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We don't even have a framework.
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We are in the pre-paradigm days, if you want to use Thomas Kuhn.
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So I fell in love with this.
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I said, look: We have all this knowledge about brains -- how hard can it be?
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It's something we can work on in my lifetime; I could make a difference.
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So I tried to get out of the computer business, into the brain business.
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First, I went to MIT, the AI lab was there.
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I said, I want to build intelligent machines too,
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but I want to study how brains work first.
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And they said, "Oh, you don't need to do that.
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You're just going to program computers, that's all.
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I said, you really ought to study brains.
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They said, "No, you're wrong."
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I said, "No, you're wrong," and I didn't get in.
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(Laughter)
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I was a little disappointed -- pretty young --
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but I went back again a few years later,
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this time in California, and I went to Berkeley.
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And I said, I'll go in from the biological side.
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So I got in the PhD program in biophysics.
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I was like, I'm studying brains now. Well, I want to study theory.
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They said, "You can't study theory about brains.
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You can't get funded for that.
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And as a graduate student, you can't do that."
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So I said, oh my gosh.
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I was depressed; I said, but I can make a difference in this field.
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I went back in the computer industry
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and said, I'll have to work here for a while.
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That's when I designed all those computer products.
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(Laughter)
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I said, I want to do this for four years, make some money,
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I was having a family, and I would mature a bit,
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and maybe the business of neuroscience would mature a bit.
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Well, it took longer than four years. It's been about 16 years.
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But I'm doing it now, and I'm going to tell you about it.
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So why should we have a good brain theory?
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Well, there's lots of reasons people do science.
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The most basic one is, people like to know things.
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We're curious, and we go out and get knowledge.
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Why do we study ants? It's interesting.
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Maybe we'll learn something useful, but it's interesting and fascinating.
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But sometimes a science has other attributes
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which makes it really interesting.
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Sometimes a science will tell something about ourselves;
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it'll tell us who we are.
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Evolution did this and Copernicus did this,
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where we have a new understanding of who we are.
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And after all, we are our brains. My brain is talking to your brain.
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Our bodies are hanging along for the ride,
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but my brain is talking to your brain.
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And if we want to understand who we are and how we feel and perceive,
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we need to understand brains.
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Another thing is sometimes science leads to big societal benefits, technologies,
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or businesses or whatever.
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This is one, too, because when we understand how brains work,
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we'll be able to build intelligent machines.
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That's a good thing on the whole,
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with tremendous benefits to society,
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just like a fundamental technology.
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So why don't we have a good theory of brains?
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People have been working on it for 100 years.
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Let's first take a look at what normal science looks like.
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This is normal science.
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Normal science is a nice balance between theory and experimentalists.
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The theorist guy says, "I think this is what's going on,"
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the experimentalist says, "You're wrong."
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It goes back and forth, this works in physics, this in geology.
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But if this is normal science, what does neuroscience look like?
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This is what neuroscience looks like.
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We have this mountain of data,
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which is anatomy, physiology and behavior.
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You can't imagine how much detail we know about brains.
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There were 28,000 people who went to the neuroscience conference this year,
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and every one of them is doing research in brains.
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A lot of data, but no theory.
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There's a little wimpy box on top there.
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And theory has not played a role in any sort of grand way
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in the neurosciences.
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And it's a real shame.
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Now, why has this come about?
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If you ask neuroscientists why is this the state of affairs,
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first, they'll admit it.
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But if you ask them, they say,
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there's various reasons we don't have a good brain theory.
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Some say we still don't have enough data,
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we need more information, there's all these things we don't know.
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Well, I just told you there's data coming out of your ears.
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We have so much information, we don't even know how to organize it.
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What good is more going to do?
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Maybe we'll be lucky and discover some magic thing, but I don't think so.
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This is a symptom of the fact that we just don't have a theory.
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We don't need more data, we need a good theory.
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Another one is sometimes people say,
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"Brains are so complex, it'll take another 50 years."
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I even think Chris said something like this yesterday, something like,
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it's one of the most complicated things in the universe.
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That's not true -- you're more complicated than your brain.
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You've got a brain.
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And although the brain looks very complicated,
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things look complicated until you understand them.
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That's always been the case.
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So we can say, my neocortex, the part of the brain I'm interested in,
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has 30 billion cells.
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But, you know what? It's very, very regular.
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In fact, it looks like it's the same thing repeated over and over again.
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It's not as complex as it looks. That's not the issue.
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Some people say, brains can't understand brains.
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Very Zen-like. Woo.
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(Laughter)
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You know, it sounds good, but why? I mean, what's the point?
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It's just a bunch of cells. You understand your liver.
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It's got a lot of cells in it too, right?
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So, you know, I don't think there's anything to that.
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And finally, some people say,
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"I don't feel like a bunch of cells -- I'm conscious.
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I've got this experience, I'm in the world.
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I can't be just a bunch of cells."
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Well, people used to believe there was a life force to be living,
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and we now know that's really not true at all.
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And there's really no evidence,
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other than that people just disbelieve that cells can do what they do.
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So some people have fallen into the pit of metaphysical dualism,
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some really smart people, too, but we can reject all that.
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(Laughter)
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No, there's something else,
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something really fundamental, and it is:
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another reason why we don't have a good brain theory
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is because we have an intuitive, strongly held but incorrect assumption
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that has prevented us from seeing the answer.
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There's something we believe that just, it's obvious, but it's wrong.
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Now, there's a history of this in science and before I tell you what it is,
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I'll tell you about the history of it in science.
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Look at other scientific revolutions --
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the solar system, that's Copernicus,
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Darwin's evolution, and tectonic plates, that's Wegener.
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They all have a lot in common with brain science.
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First, they had a lot of unexplained data. A lot of it.
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But it got more manageable once they had a theory.
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The best minds were stumped -- really smart people.
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We're not smarter now than they were then;
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it just turns out it's really hard to think of things,
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but once you've thought of them, it's easy to understand.
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My daughters understood these three theories,
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in their basic framework, in kindergarten.
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It's not that hard -- here's the apple, here's the orange,
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the Earth goes around, that kind of stuff.
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Another thing is the answer was there all along,
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but we kind of ignored it because of this obvious thing.
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It was an intuitive, strongly held belief that was wrong.
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In the case of the solar system,
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the idea that the Earth is spinning,
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the surface is going a thousand miles an hour,
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and it's going through the solar system at a million miles an hour --
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this is lunacy; we all know the Earth isn't moving.
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Do you feel like you're moving a thousand miles an hour?
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If you said Earth was spinning around in space and was huge --
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they would lock you up, that's what they did back then.
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So it was intuitive and obvious. Now, what about evolution?
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Evolution, same thing.
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We taught our kids the Bible says God created all these species,
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cats are cats; dogs are dogs; people are people; plants are plants;
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they don't change.
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Noah put them on the ark in that order, blah, blah.
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The fact is, if you believe in evolution, we all have a common ancestor.
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We all have a common ancestor with the plant in the lobby!
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This is what evolution tells us. And it's true. It's kind of unbelievable.
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And the same thing about tectonic plates.
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All the mountains and the continents
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are kind of floating around on top of the Earth.
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It doesn't make any sense.
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So what is the intuitive, but incorrect assumption,
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that's kept us from understanding brains?
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I'll tell you. It'll seem obvious that it's correct. That's the point.
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Then I'll make an argument why you're incorrect on the other assumption.
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The intuitive but obvious thing is:
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somehow, intelligence is defined by behavior;
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we're intelligent because of how we do things
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and how we behave intelligently.
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And I'm going to tell you that's wrong.
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Intelligence is defined by prediction.
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I'm going to work you through this in a few slides,
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and give you an example of what this means.
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Here's a system.
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Engineers and scientists like to look at systems like this.
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They say, we have a thing in a box. We have its inputs and outputs.
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The AI people said, the thing in the box is a programmable computer,
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because it's equivalent to a brain.
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We'll feed it some inputs and get it to do something, have some behavior.
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Alan Turing defined the Turing test, which essentially says,
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we'll know if something's intelligent if it behaves identical to a human --
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a behavioral metric of what intelligence is
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that has stuck in our minds for a long time.
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Reality, though -- I call it real intelligence.
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Real intelligence is built on something else.
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We experience the world through a sequence of patterns,
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and we store them, and we recall them.
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When we recall them, we match them up against reality,
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and we're making predictions all the time.
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It's an internal metric; there's an internal metric about us,
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saying, do we understand the world, am I making predictions, and so on.
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You're all being intelligent now, but you're not doing anything.
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Maybe you're scratching yourself, but you're not doing anything.
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But you're being intelligent; you're understanding what I'm saying.
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Because you're intelligent and you speak English,
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you know the word at the end of this
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sentence.
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The word came to you; you make these predictions all the time.
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What I'm saying is,
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the internal prediction is the output in the neocortex,
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and somehow, prediction leads to intelligent behavior.
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Here's how that happens:
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Let's start with a non-intelligent brain.
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I'll argue a non-intelligent brain, we'll call it an old brain.
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And we'll say it's a non-mammal, like a reptile,
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say, an alligator; we have an alligator.
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And the alligator has some very sophisticated senses.
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It's got good eyes and ears and touch senses and so on,
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a mouth and a nose.
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It has very complex behavior.
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It can run and hide. It has fears and emotions. It can eat you.
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It can attack. It can do all kinds of stuff.
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But we don't consider the alligator very intelligent,
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not in a human sort of way.
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But it has all this complex behavior already.
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Now in evolution, what happened?
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First thing that happened in evolution with mammals
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is we started to develop a thing called the neocortex.
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I'm going to represent the neocortex by this box on top of the old brain.
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Neocortex means "new layer." It's a new layer on top of your brain.
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It's the wrinkly thing on the top of your head
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that got wrinkly because it got shoved in there and doesn't fit.
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(Laughter)
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Literally, it's about the size of a table napkin
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and doesn't fit, so it's wrinkly.
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Now, look at how I've drawn this.
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The old brain is still there.
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You still have that alligator brain. You do. It's your emotional brain.
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It's all those gut reactions you have.
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On top of it, we have this memory system called the neocortex.
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And the memory system is sitting over the sensory part of the brain.
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So as the sensory input comes in and feeds from the old brain,
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it also goes up into the neocortex.
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And the neocortex is just memorizing.
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It's sitting there saying, I'm going to memorize all the things going on:
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where I've been, people I've seen, things I've heard, and so on.
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And in the future, when it sees something similar to that again,
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in a similar environment, or the exact same environment,
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it'll start playing it back: "Oh, I've been here before,"
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and when you were here before, this happened next.
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It allows you to predict the future.
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It literally feeds back the signals into your brain;
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they'll let you see what's going to happen next,
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will let you hear the word "sentence" before I said it.
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And it's this feeding back into the old brain
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that will allow you to make more intelligent decisions.
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This is the most important slide of my talk, so I'll dwell on it a little.
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And all the time you say, "Oh, I can predict things,"
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so if you're a rat and you go through a maze, and you learn the maze,
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next time you're in one, you have the same behavior.
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But suddenly, you're smarter; you say, "I recognize this maze,
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I know which way to go; I've been here before; I can envision the future."
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That's what it's doing.
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This is true for all mammals --
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in humans, it got a lot worse.
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Humans actually developed the front of the neocortex,
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called the anterior part of the neocortex.
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And nature did a little trick.
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It copied the posterior, the back part, which is sensory,
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and put it in the front.
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Humans uniquely have the same mechanism on the front,
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but we use it for motor control.
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So we're now able to do very sophisticated motor planning, things like that.
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I don't have time to explain, but to understand how a brain works,
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you have to understand how the first part of the mammalian neocortex works,
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how it is we store patterns and make predictions.
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Let me give you a few examples of predictions.
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I already said the word "sentence."
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In music, if you've heard a song before,
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when you hear it, the next note pops into your head already --
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you anticipate it.
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With an album, at the end of a song, the next song pops into your head.
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It happens all the time, you make predictions.
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I have this thing called the "altered door" thought experiment.
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It says, you have a door at home;
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when you're here, I'm changing it --
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I've got a guy back at your house right now, moving the door around,
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moving your doorknob over two inches.
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When you go home tonight, you'll put your hand out, reach for the doorknob,
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notice it's in the wrong spot
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and go, "Whoa, something happened."
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It may take a second, but something happened.
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I can change your doorknob in other ways --
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make it larger, smaller, change its brass to silver, make it a lever,
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I can change the door; put colors on, put windows in.
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I can change a thousand things about your door
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and in the two seconds you take to open it,
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you'll notice something has changed.
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Now, the engineering approach, the AI approach to this,
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is to build a door database with all the door attributes.
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And as you go up to the door, we check them off one at time:
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door, door, color ...
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We don't do that. Your brain doesn't do that.
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Your brain is making constant predictions all the time
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about what will happen in your environment.
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As I put my hand on this table, I expect to feel it stop.
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When I walk, every step, if I missed it by an eighth of an inch,
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I'll know something has changed.
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You're constantly making predictions about your environment.
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I'll talk about vision, briefly.
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This is a picture of a woman.
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When we look at people, our eyes saccade over two to three times a second.
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We're not aware of it, but our eyes are always moving.
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When we look at a face, we typically go from eye to eye to nose to mouth.
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When your eye moves from eye to eye,
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if there was something else there like a nose,
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you'd see a nose where an eye is supposed to be and go, "Oh, shit!"
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(Laughter)
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"There's something wrong about this person."
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That's because you're making a prediction.
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It's not like you just look over and say, "What am I seeing? A nose? OK."
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No, you have an expectation of what you're going to see.
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Every single moment.
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And finally, let's think about how we test intelligence.
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We test it by prediction: What is the next word in this ...?
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This is to this as this is to this. What is the next number in this sentence?
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Here's three visions of an object. What's the fourth one?
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That's how we test it. It's all about prediction.
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16:57
So what is the recipe for brain theory?
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First of all, we have to have the right framework.
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And the framework is a memory framework,
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not a computational or behavior framework,
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it's a memory framework.
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How do you store and recall these sequences of patterns?
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17:10
It's spatiotemporal patterns.
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Then, if in that framework, you take a bunch of theoreticians --
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17:14
biologists generally are not good theoreticians.
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Not always, but generally, there's not a good history of theory in biology.
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I've found the best people to work with are physicists,
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engineers and mathematicians,
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17:24
who tend to think algorithmically.
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Then they have to learn the anatomy and the physiology.
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You have to make these theories very realistic in anatomical terms.
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Anyone who tells you their theory about how the brain works
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and doesn't tell you exactly how it's working
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and how the wiring works --
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it's not a theory.
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And that's what we do at the Redwood Neuroscience Institute.
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I'd love to tell you we're making fantastic progress in this thing,
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and I expect to be back on this stage sometime in the not too distant future,
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to tell you about it.
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I'm really excited; this is not going to take 50 years.
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17:55
What will brain theory look like?
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First of all, it's going to be about memory.
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17:59
Not like computer memory -- not at all like computer memory.
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It's very different.
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It's a memory of very high-dimensional patterns,
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like the things that come from your eyes.
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18:07
It's also memory of sequences:
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18:08
you cannot learn or recall anything outside of a sequence.
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18:11
A song must be heard in sequence over time,
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18:14
and you must play it back in sequence over time.
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18:16
And these sequences are auto-associatively recalled,
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18:19
so if I see something, I hear something, it reminds me of it,
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18:22
and it plays back automatically.
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18:23
It's an automatic playback.
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18:25
And prediction of future inputs is the desired output.
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18:27
And as I said, the theory must be biologically accurate,
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18:30
it must be testable and you must be able to build it.
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If you don't build it, you don't understand it.
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18:35
One more slide.
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What is this going to result in?
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Are we going to really build intelligent machines?
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Absolutely. And it's going to be different than people think.
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No doubt that it's going to happen, in my mind.
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First of all, we're going to build this stuff out of silicon.
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The same techniques we use to build silicon computer memories,
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18:54
we can use here.
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18:55
But they're very different types of memories.
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18:57
And we'll attach these memories to sensors,
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18:59
and the sensors will experience real-live, real-world data,
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19:02
and learn about their environment.
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19:03
Now, it's very unlikely the first things you'll see are like robots.
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19:07
Not that robots aren't useful; people can build robots.
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19:10
But the robotics part is the hardest part. That's old brain. That's really hard.
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The new brain is easier than the old brain.
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So first we'll do things that don't require a lot of robotics.
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So you're not going to see C-3PO.
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19:21
You're going to see things more like intelligent cars
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that really understand what traffic is, what driving is
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19:26
and have learned that cars with the blinkers on for half a minute
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19:29
probably aren't going to turn.
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19:31
(Laughter)
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We can also do intelligent security systems.
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Anytime we're basically using our brain but not doing a lot of mechanics --
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those are the things that will happen first.
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But ultimately, the world's the limit.
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I don't know how this will turn out.
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I know a lot of people who invented the microprocessor.
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And if you talk to them,
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they knew what they were doing was really significant,
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19:51
but they didn't really know what was going to happen.
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They couldn't anticipate cell phones and the Internet
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19:56
and all this kind of stuff.
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They just knew like, "We're going to build calculators
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and traffic-light controllers.
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But it's going to be big!"
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In the same way, brain science and these memories
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20:06
are going to be a very fundamental technology,
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20:08
and it will lead to unbelievable changes in the next 100 years.
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20:12
And I'm most excited about how we're going to use them in science.
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So I think that's all my time -- I'm over,
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and I'm going to end my talk right there.
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About this website

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