What is going on in baby’s mind? If you’d asked people this 30 years ago, most people, including psychologists, would said that this baby was irrational, illogical, egocentric — that he couldn’t take the perspective of another or understand cause and effect. In the last 20 years, developmental science completely overturned that picture. So in some ways, we think that this baby’s thinking is like the of the most brilliant scientists.
Let me give you just one example of this. One that this baby could be thinking about, that could be going on in his mind, is trying to out what’s going on in the mind of that other baby. all, one of the things that’s hardest for all of to do is to figure out what other people thinking and feeling. And maybe the hardest thing of all is to figure out that what other think and feel isn’t actually exactly like what we think and feel. who’s followed politics can testify to how hard that is some people to get. We wanted to know if babies and young children could understand this profound thing about other people. Now the question is: could we ask them? Babies, after all, can’t talk, and you ask a three year-old to tell you what he thinks, what you’ll get is a beautiful of consciousness monologue about ponies and birthdays and things like that. So how do we actually ask the question?
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Well it turns out that secret was broccoli. What we did — Betty Rapacholi, who was one my students, and I — was actually to give the two bowls of food: one bowl of raw broccoli one bowl of delicious goldfish crackers. Now all of the babies, even in Berkley, like the crackers don’t like the raw broccoli. (Laughter) But then what Betty did was to take a little taste of from each bowl. And she would act as if she liked or she didn’t. So half the time, she acted as if she liked crackers and didn’t like the broccoli — just like a baby and any other sane person. But the time, what she would do is take a little bit of the broccoli and go, “Mmmmm, broccoli. tasted the broccoli. Mmmmm.” And then she would take a bit of the crackers, and she’d go, “Eww, yuck, crackers. I tasted the crackers. Eww, yuck.” she’d act as if what she wanted was just the opposite of what the babies wanted. did this with 15 and 18 month-old babies. And then she would put her hand out and say, “Can you give me some?”
So question is: What would the baby give her, what they liked or what she liked? And remarkable thing was that 18 month-old babies, just barely and talking, would give her the crackers if she the crackers, but they would give her the broccoli she liked the broccoli. On the other hand, 15 month-olds would stare at her a long time if she acted as if she liked the broccoli, they couldn’t figure this out. But then after they stared for a long time, they would give her the crackers, what they thought everybody must like. So there are really remarkable things about this. The first one is that these little 18 month-old babies have already discovered really profound fact about human nature, that we don’t always want same thing. And what’s more, they felt that they should actually do things to help other people what they wanted.
Even more remarkably though, the fact that 15 month-olds didn’t this suggests that these 18 month-olds had learned this deep, profound fact about human nature in the three from when they were 15 months old. So children know more and learn more than we ever would have thought. this is just one of hundreds and hundreds of studies over the 20 years that’s actually demonstrated it.
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The question you might though is: Why do children learn so much? And how is it possible for them to learn much in such a short time? I mean, after all, if you look at superficially, they seem pretty useless. And actually in many ways, they’re worse than useless, we have to put so much time and energy into just keeping them alive. But if we turn evolution for an answer to this puzzle of why we spend so time taking care of useless babies, it turns out that there’s an answer. If we look across many, many different species animals, not just us primates, but also including other mammals, birds, even marsupials like kangaroos wombats, it turns out that there’s a relationship between how long a childhood species has and how big their brains are compared their bodies and how smart and flexible they are.
And sort of the for this idea are the birds up there. On one side is New Caledonian crow. And crows and other corvidae, ravens, rooks so forth, are incredibly smart birds. They’re as smart chimpanzees in some respects. And this is a bird on the cover of science who’s learned to use a tool to get food. On the other hand, we have our friend domestic chicken. And chickens and ducks and geese and turkeys basically as dumb as dumps. So they’re very, very good pecking for grain, and they’re not much good at doing anything else. Well it turns that the babies, the New Caledonian crow babies, are fledglings. They depend on moms to drop worms in their little open mouths for long as two years, which is a really long time in the life of a bird. Whereas the are actually mature within a couple of months. So childhood is the reason why the crows end on the cover of Science and the chickens end up the soup pot.
There’s something about that long childhood that to be connected to knowledge and learning. Well what kind of explanation could we have for this? Well animals, like the chicken, seem to be beautifully suited to doing just one thing very well. So they to be beautifully suited to pecking grain in one environment. Other creatures, like the crows, aren’t very at doing anything in particular, but they’re extremely good learning about laws of different environments.
And of course, we human beings are way on the end of the distribution like the crows. We bigger brains relative to our bodies by far than other animal. We’re smarter, we’re more flexible, we can learn more, we survive in different environments, we migrated to cover the world and even go outer space. And our babies and children are dependent on us for longer than the babies of any other species. My son 23. (Laughter) And at least until they’re 23, we’re still popping those worms those little open mouths.
All right, why would we see this correlation? Well an is that that strategy, that learning strategy, is an extremely powerful, great strategy for getting on in world, but it has one big disadvantage. And that one big disadvantage is that, until you actually all that learning, you’re going to be helpless. So don’t want to have the mastodon charging at you be saying to yourself, “A slingshot or maybe a spear might work. would actually be better?” You want to know all that before the mastodons actually show up. And the the evolutions seems to have solved that problem is a kind of division of labor. So the idea that we have this early period when we’re completely protected. don’t have to do anything. All we have to do is learn. And as adults, we can take all those things that we learned when we babies and children and actually put them to work to things out there in the world.
So one way of thinking about it is that and young children are like the research and development division the human species. So they’re the protected blue sky who just have to go out and learn and good ideas, and we’re production and marketing. We have take all those ideas that we learned when we were children and actually put to use. Another way of thinking about it is instead of of babies and children as being like defective grownups, we should about them as being a different developmental stage of the same species — kind of caterpillars and butterflies — except that they’re actually the brilliant butterflies are flitting around the garden and exploring, and we’re the caterpillars who inching along our narrow, grownup, adult path.
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If is true, if these babies are designed to learn — this evolutionary story would say children are for learning, that’s what they’re for — might expect that they would have really powerful learning mechanisms. in fact, the baby’s brain seems to be the most powerful computer on the planet. But real computers are actually getting to a lot better. And there’s been a revolution in our of machine learning recently. And it all depends on the ideas this guy, the Reverend Thomas Bayes, who was a statistician and mathematician the 18th century. And essentially what Bayes did was to provide a mathematical way using theory to characterize, describe, the way that scientists find out about the world. So scientists do is they have a hypothesis that they think might be likely to start with. go out and test it against the evidence. The evidence makes them that hypothesis. Then they test that new hypothesis and on and so forth. And what Bayes showed was a mathematical that you could do that. And that mathematics is the core of the best machine learning programs that have now. And some 10 years ago, I suggested that might be doing the same thing.
So if you want know what’s going on underneath those beautiful brown eyes, I think actually looks something like this. This is Reverend Bayes’s notebook. So I think those babies are making complicated calculations with conditional probabilities that they’re revising to figure out how the works. All right, now that might seem like an even order to actually demonstrate. Because after all, if you ask grownups about statistics, they look extremely stupid. How could it be that children are doing statistics?
So to this we used a machine that we have called the Blicket Detector. This a box that lights up and plays music when you put things on it and not others. And using this very simple machine, lab and others have done dozens of studies showing just good babies are at learning about the world. Let me mention one that we did with Tumar Kushner, my student. If I showed you this detector, you be likely to think to begin with that the to make the detector go would be to put a on top of the detector. But actually, this detector works in a bit of a strange way. Because you wave a block over the top of the detector, something you wouldn’t think of to begin with, the detector will actually activate two out three times. Whereas, if you do the likely thing, put the on the detector, it will only activate two out of six times. So the unlikely hypothesis has stronger evidence. It looks as if the waving a more effective strategy than the other strategy. So we did just this; we four year-olds this pattern of evidence, and we just asked to make it go. And sure enough, the four year-olds used the evidence to wave object on top of the detector.
Now there are two things that are really interesting this. The first one is, again, remember, these are four year-olds. They’re just learning to count. But unconsciously, they’re doing these quite complicated that will give them a conditional probability measure. And the other interesting thing is that they’re using that to get to an idea, get to a hypothesis about the world, that very unlikely to begin with. And in studies we’ve just been doing my lab, similar studies, we’ve show that four year-olds are actually better at finding out unlikely hypothesis than adults are when we give them exactly the task. So in these circumstances, the children are using statistics to find out the world, but after all, scientists also do experiments, and we wanted to if children are doing experiments. When children do experiments we call it “getting into everything” or “playing.”
And there’s been a bunch of interesting studies that have shown this playing around is really a kind of experimental program. Here’s one from Cristine Legare’s lab. What Cristine did was use our Blicket Detectors. And she did was show children that yellow ones made it go red ones didn’t, and then she showed them an anomaly. And you’ll see is that this little boy will go through hypotheses in the space of two minutes.
(Video) Boy: How this? Same as the other side.
Alison Gopnik: Okay, so his first hypothesis just been falsified.
(Laughter)
Boy: This one lighted up, and this one nothing.
AG: Okay, he’s got experimental notebook out.
Boy: What’s making this light up. (Laughter) don’t know.
AG: Every scientist will recognize that expression despair.
(Laughter)
Boy: Oh, it’s because this needs to like this, and this needs to be like this.
AG: Okay, hypothesis two.
Boy: That’s why. Oh.
(Laughter)
AG: this is his next idea. He told the experimenter to this, to try putting it out onto the other location. Not either.
Boy: Oh, because the light goes only to here, not here. Oh, bottom of this box has electricity in here, but doesn’t have electricity.
AG: Okay, that’s a fourth hypothesis.
Boy: It’s lighting up. when you put four. So you put four on this one to make light up and two on this one to make it up.
AG: Okay,there’s his fifth hypothesis.
Now that is particularly — that is a particularly adorable and articulate little boy, but Cristine discovered is this is actually quite typical. If you look the way children play, when you ask them to explain something, what they do is do a series of experiments. This is actually pretty typical of year-olds.
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Well, what’s it like to be kind of creature? What’s it like to be one of these brilliant butterflies can test five hypotheses in two minutes? Well, if you go back those psychologists and philosophers, a lot of them have said that babies and young were barely conscious if they were conscious at all. And think just the opposite is true. I think babies children are actually more conscious than we are as adults. Now here’s we know about how adult consciousness works. And adults’ and consciousness look kind of like a spotlight. So what for adults is we decide that something’s relevant or important, we pay attention to it. Our consciousness of that thing that we’re to becomes extremely bright and vivid, and everything else sort of goes dark. And we even something about the way the brain does this.
So what happens when pay attention is that the prefrontal cortex, the sort of part of our brains, sends a signal that makes little part of our brain much more flexible, more plastic, at learning, and shuts down activity in all the rest our brains. So we have a very focused, purpose-driven kind attention. If we look at babies and young children, see something very different. I think babies and young children seem to have of a lantern of consciousness than a spotlight of consciousness. So babies and young children are very at narrowing down to just one thing. But they’re very good taking in lots of information from lots of different at once. And if you actually look in their brains, you see that they’re with these neurotransmitters that are really good at inducing learning plasticity, and the inhibitory parts haven’t come on yet. when we say that babies and young children are bad paying attention, what we really mean is that they’re bad not paying attention. So they’re bad at getting rid of the interesting things that could tell them something and just looking the thing that’s important. That’s the kind of attention, the kind of consciousness, that we might expect from butterflies who are designed to learn.
Well if we want to about a way of getting a taste of that kind of baby as adults, I think the best thing is think cases where we’re put in a new situation that we’ve never in before — when we fall in love with new, or when we’re in a new city for first time. And what happens then is not that our contracts, it expands, so that those three days in Paris seem be more full of consciousness and experience than all the of being a walking, talking, faculty meeting-attending zombie back home. by the way, that coffee, that wonderful coffee you’ve been drinking downstairs, mimics the effect of those baby neurotransmitters. So what’s it like be a baby? It’s like being in love in Paris for the first time after you’ve three double-espressos. (Laughter) That’s a fantastic way to be, but it does tend to leave you up crying at three o’clock in the morning.
(Laughter)
Now it’s good to be a grownup. I don’t want to too much about how wonderful babies are. It’s good to be a grownup. We can do things like our shoelaces and cross the street by ourselves. And makes sense that we put a lot of effort into making think like adults do. But if what we want is to be like butterflies, to have open-mindedness, open learning, imagination, creativity, innovation, maybe least some of the time we should be getting adults to start thinking more like children.
(Applause)