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