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