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 of another person or understand cause effect. In the last 20 years, developmental science has completely overturned that picture. So in some ways, think that this baby’s thinking is like the thinking of the most brilliant scientists.
Let me give just one example of this. One thing that this could be thinking about, that could be going on in his mind, is trying figure out what’s going on in the mind of that other baby. After all, one the things that’s hardest for all of us to do is figure out what other people are thinking and feeling. maybe the hardest thing of all is to figure out what other people think and feel isn’t actually exactly like what think and feel. Anyone who’s followed politics can testify to how hard that is for some people get. We wanted to know if babies and young children could understand this really thing about other people. Now the question is: How could we them? Babies, after all, can’t talk, and if you ask a year-old to tell you what he thinks, what you’ll is a beautiful stream of consciousness monologue about ponies and birthdays things like that. So how do we actually ask the question?
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Well it turns out that the secret was broccoli. we did — Betty Rapacholi, who was one of students, and I — was actually to give the babies two bowls of food: bowl of raw broccoli and one bowl of delicious goldfish crackers. Now all of the babies, even Berkley, like the crackers and don’t like the raw broccoli. (Laughter) But what Betty did was to take a little taste of food each bowl. And she would act as if she liked it or didn’t. So half the time, she acted as if she liked the crackers and didn’t like the — just like a baby and any other sane person. half the time, what she would do is take a little of the broccoli and go, “Mmmmm, broccoli. I tasted the broccoli. Mmmmm.” And then she take a little bit of the crackers, and she’d go, “Eww, yuck, crackers. I tasted crackers. Eww, yuck.” So she’d act as if what she wanted was just the opposite what the babies wanted. We 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 question is: What would the baby give her, what liked or what she liked? And the remarkable thing was that 18 month-old babies, barely walking and talking, would give her the crackers if she liked the crackers, they would give her the broccoli if she liked the broccoli. 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 her crackers, what they thought everybody must like. So there two really remarkable things 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 that they should actually do things to other people get what they wanted.
Even more remarkably though, the fact that 15 month-olds didn’t this 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 learn more we ever would have thought. And this is just of hundreds and hundreds of studies over the last 20 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 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 keeping them alive. But if we to evolution for an answer to this puzzle of why we spend so much taking care of useless babies, it turns out that there’s actually an answer. If look across many, many different species of animals, not 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 to their bodies and how smart flexible they are.
And sort of the posterbirds for this idea are the birds there. On one side is a New Caledonian crow. And crows and other corvidae, ravens, rooks so forth, are incredibly smart birds. They’re as smart as in some respects. And this is a bird on the cover of who’s learned how to use a tool to get food. On the hand, we have our friend the domestic chicken. And chickens and and geese and turkeys are basically as dumb as dumps. So they’re very, very good at 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 open for as long as two years, which is a really long in the life of a bird. Whereas the chickens are actually mature within a of months. So childhood is the reason why the crows end up on the cover of and the chickens end up in the soup pot.
There’s about that long childhood that seems to be connected to knowledge and learning. Well what of explanation could we have for this? Well some animals, the chicken, seem to be beautifully suited to doing one thing very well. So they seem to be suited to pecking grain in one environment. Other creatures, like crows, aren’t very good at doing 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 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 and even go to outer space. And our babies and children are dependent on us for much longer the babies of any other species. My son is 23. (Laughter) And at until 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 that strategy, learning strategy, is an extremely powerful, great strategy for getting on in world, but it has one big disadvantage. And that one big disadvantage is that, until you do all that learning, you’re going to be helpless. you don’t want to have the mastodon charging at you be saying to yourself, “A slingshot or maybe a might work. Which would actually be better?” You want to 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. So the idea that we have this early period when we’re completely protected. We don’t have to anything. All we have to do is learn. And then as adults, can take all those things that we learned when we were babies and children and actually put them work to 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 blue sky guys who just have to go out and learn and good ideas, and we’re production and marketing. We have to take all those ideas we learned when we were children and actually put to use. Another way of thinking about it is of thinking of babies and children as being like grownups, we should think about them as being a different developmental stage the same species — kind of like caterpillars and butterflies — that they’re actually the brilliant butterflies who are flitting the garden and exploring, and we’re the caterpillars who are along our narrow, grownup, adult path.
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If this is true, if these are designed to learn — and this evolutionary story would say children for learning, that’s what they’re for — we might expect that they 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 are actually getting be a lot better. And there’s been a revolution our understanding of machine learning recently. And it all depends the ideas of this guy, the Reverend Thomas Bayes, was a statistician and mathematician in the 18th century. And essentially Bayes did was to provide a mathematical way using probability theory to characterize, describe, way that scientists find out about the world. So what scientists do is have a 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 and so forth. And what Bayes showed was a mathematical way that you could that. And that mathematics is at the core of the best learning programs that we have now. And some 10 ago, I suggested that babies 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 actually making complicated calculations with conditional probabilities that they’re revising to out how the world works. All right, now that might seem like an even taller order actually demonstrate. Because after all, if you ask even grownups statistics, they look extremely stupid. How could it be that children are doing statistics?
So to this we used a machine that we have called the Blicket Detector. This a box that lights up and plays music when you some things on it and not others. And using this very machine, my lab and others have done dozens of studies just how good babies are at learning about the world. me mention just one that we did with Tumar Kushner, student. If I showed you this detector, you would likely to think to begin with that the way to the detector go would be to put a block top of the detector. But actually, this detector works in a bit of a way. Because if you wave a block over the of the detector, something you wouldn’t ever think of to begin with, detector will actually activate two out of three times. Whereas, if you do likely thing, put the block on the detector, it will activate two 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 did just this; we gave four year-olds this pattern of evidence, and just asked them to make it go. And sure enough, the four year-olds used the evidence to wave the on top of the detector.
Now there are two things that are really interesting about this. first one is, again, remember, these are four year-olds. They’re learning how to count. But unconsciously, they’re doing these complicated calculations that will give them a conditional probability measure. And the other thing is that they’re using that evidence to get to an idea, get to a hypothesis the world, that seems very unlikely to begin with. And in we’ve just been doing in my lab, similar studies, we’ve show that four year-olds are actually at finding out an unlikely hypothesis than adults are when we give them exactly same task. So in these circumstances, the children are using statistics to find about the world, but after all, scientists also do experiments, and we wanted see if children are doing experiments. When children do experiments call it “getting into 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. And she did was show children that yellow ones made it go and red ones didn’t, then she showed them an anomaly. And what you’ll is that this little boy will go through five in the space of two minutes.
(Video) Boy: How about this? as the other side.
Alison Gopnik: Okay, so his hypothesis has just been falsified.
(Laughter)
Boy: This one up, and this 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 recognize that expression of despair.
(Laughter)
Boy: Oh, it’s this needs to be like this, and this needs be like 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 try putting it onto the other location. Not working either.
Boy: Oh, because the light 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 up. So when you put four. So you put four on this to make it light up and two on this one to make it light up.
AG: Okay,there’s fifth hypothesis.
Now that is a particularly — that 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, when you them to explain something, what they really do 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 of creature? What’s it to be one of these brilliant butterflies who can test five in two minutes? Well, if you go back to those and philosophers, a lot of them have said that babies and young were barely conscious if they were conscious at all. And I just the opposite is true. I think babies and children are actually more than we are as adults. Now here’s what we know about adult consciousness works. And adults’ attention and consciousness look kind like a spotlight. So what happens for adults is decide that something’s relevant or important, we should pay attention to it. Our of that thing that we’re attending to becomes extremely bright and vivid, and 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 much more flexible, more plastic, better at learning, and down activity in all the rest of our brains. So we a very focused, purpose-driven kind of attention. If we look at babies and young children, we see very different. I think babies 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 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 in their brains, see that they’re flooded with these neurotransmitters that are really good inducing learning and plasticity, and the inhibitory parts haven’t come on yet. when we say that babies and young children are bad paying attention, what we really mean is that they’re at not paying attention. So they’re bad at getting rid of the interesting things that could tell them something and just looking the thing that’s important. That’s the kind of attention, kind of consciousness, that we might expect from those butterflies who are designed learn.
Well if we want to think about a way of getting a taste that kind of baby consciousness as adults, I think the thing is think about cases where we’re put in a situation that we’ve never been in before — when fall in love with someone new, or when we’re in a new city 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 wonderful coffee you’ve been drinking downstairs, actually the effect of those baby neurotransmitters. So what’s it like to a baby? It’s like being in love in Paris for the first time you’ve had three double-espressos. (Laughter) That’s a fantastic way to be, but it 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 too about how wonderful babies are. It’s good to be a grownup. We 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. if what we want is to be like those butterflies, to open-mindedness, open learning, imagination, creativity, innovation, maybe at least some the time we should be getting the adults to thinking more like children.
(Applause)