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