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