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