What is going on this baby’s mind? If you’d asked people this 30 years ago, people, including psychologists, would have said that this baby irrational, illogical, egocentric — that he couldn’t take the perspective another person or understand cause 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. One thing that this baby be thinking about, that could be going on in his mind, is trying to figure out what’s going in the mind of that other baby. After all, of the things that’s hardest for all of us to is to figure out what other people are thinking and feeling. And maybe the hardest thing all is to figure out that what other people think and isn’t actually exactly like what we think and feel. Anyone who’s politics can testify to how hard that is for some people get. We wanted to know if babies and young could understand this really profound thing about other people. Now the is: How could we ask them? Babies, after all, can’t talk, and you ask a three year-old to tell you what thinks, what you’ll get is a beautiful stream of monologue about ponies and birthdays and things like that. So how do actually ask them the question?
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Well it turns out the secret was broccoli. What we did — Betty Rapacholi, who one of my students, and I — was actually to give the babies two bowls food: one bowl of raw broccoli and one bowl delicious goldfish crackers. Now all of the babies, even in Berkley, like the and don’t like the raw broccoli. (Laughter) But then Betty did was to take a little taste of food from each bowl. And she act as if she liked it or she didn’t. So half time, she acted as if she liked the crackers and didn’t like the — just like a baby and any other sane person. But half time, what she would do is take a little bit of broccoli and go, “Mmmmm, broccoli. I tasted the broccoli. Mmmmm.” And then she would take a bit of the crackers, and she’d go, “Eww, yuck, crackers. I tasted the crackers. Eww, yuck.” So she’d act if what she wanted was just the opposite of what the babies wanted. did 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: would the baby give her, what they liked or what she liked? And remarkable thing was that 18 month-old babies, just barely and talking, would give her the crackers if she liked crackers, but they would give her the broccoli if liked the broccoli. On the other hand, 15 month-olds would at her for a long time if she acted if she liked the broccoli, like they couldn’t figure this out. But after they stared for a long time, they would just give her the crackers, what they thought must like. So there are two really remarkable things about this. The first one is that these 18 month-old babies have already discovered this really profound fact human nature, that we don’t always want the same thing. And what’s more, they felt that they actually do things to help other people get what they wanted.
Even remarkably though, the fact that 15 month-olds didn’t do this that these 18 month-olds had learned this deep, profound about human nature in the three months from when they were 15 old. So children both know more and learn more than we would have thought. And this is just one of hundreds and of studies over the last 20 years that’s actually it.
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The question you might ask though is: Why do learn so much? And how is it possible for them to learn much 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 to put so much time and energy into just keeping them alive. But if turn to evolution for an answer to this puzzle why we spend so much time taking care of babies, it turns out that there’s actually an answer. we look across many, many different species of animals, just us primates, but also including other mammals, birds, even marsupials kangaroos and wombats, it turns out that there’s a relationship between how long a a species has and how big their brains are compared to bodies and how smart and flexible they are.
And sort of the posterbirds for idea are the birds up there. On one side is New Caledonian crow. And crows and other corvidae, ravens, rooks so forth, are incredibly smart birds. They’re as smart chimpanzees in some respects. And this is a bird on the cover of who’s learned how to use a tool to get food. the other hand, we have our friend the domestic chicken. chickens 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 good at anything else. Well it turns out that the babies, the Caledonian crow babies, are fledglings. They depend on their moms to worms in their little open mouths for as long two years, which is a really long time in the life of a bird. Whereas chickens are actually mature within a couple of months. childhood is the reason why the crows end up 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. Well what kind of explanation could we have this? Well some animals, like the chicken, seem to be beautifully to doing just one thing very well. So they seem to be suited to pecking grain in one environment. Other creatures, 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, we human beings are out on the end of the distribution like the crows. We bigger brains relative to our bodies by far than other animal. We’re smarter, we’re more flexible, we can learn more, survive in more different environments, we migrated to cover world and even go to outer space. And our and children are dependent on us for much longer than the babies of any species. My son is 23. (Laughter) And at least until they’re 23, we’re still popping those into those little open mouths.
All right, why would we see this correlation? an idea is that that strategy, that learning strategy, is an extremely powerful, great for getting on in the world, but it has one big disadvantage. And that one big is that, until you actually do all that learning, you’re going to helpless. So you don’t want to have the mastodon at you and be saying to yourself, “A slingshot or a spear might work. Which would actually be better?” You want to know all that the mastodons actually show up. And the way the evolutions seems to have solved 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 to is learn. And then as adults, we can take all those things we learned when we were babies and children and actually put them to work to do things there in the world.
So one way of thinking about is that babies and young children are like the research development division of the human species. So they’re the blue sky guys who just have to go out learn and have good ideas, and we’re production and marketing. have to take all those ideas that we learned when we were children actually put them to use. Another way of thinking about it instead of thinking of babies and children as being defective grownups, we should think about them as being a developmental stage of the same species — kind of caterpillars and butterflies — except that they’re actually the brilliant who are flitting around the garden and exploring, and we’re the caterpillars who are 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 what they’re — we might expect that they would have really powerful mechanisms. And in fact, the baby’s brain seems to be the most powerful learning computer on planet. But real computers are actually getting to be a lot better. there’s been a revolution in our understanding of machine learning recently. And it all on the ideas of this guy, the Reverend Thomas Bayes, was a statistician and mathematician in the 18th century. And essentially what did was to provide a mathematical way using probability theory to characterize, describe, the way scientists find out 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. The evidence them change that hypothesis. Then they test that new 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, suggested that babies might be doing the same thing.
So if want to know what’s going on underneath those beautiful eyes, I think it actually looks something like this. This is Reverend Bayes’s notebook. So I think babies are actually making complicated calculations with conditional probabilities that they’re revising to figure how the world works. All right, now that might seem like an even order to actually demonstrate. Because after all, if you ask even grownups about statistics, they look extremely stupid. could it be that children are doing statistics?
So to test this we used machine that we have called the Blicket Detector. This is a box lights up and plays music when you put some on it and not others. And using this very simple machine, my lab and others have done dozens studies showing just how good babies are at learning about the world. Let me just one that we did with Tumar Kushner, my student. If I showed you detector, you would be likely to think to begin with that the way to make the detector would be to put a block on top of the detector. But actually, this detector works in a of a strange way. Because if you wave a over the top of the detector, something you wouldn’t ever think of to with, the detector will actually activate two out of times. Whereas, if you do the likely thing, put the block 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 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 on top of the detector.
Now are two things that are really interesting about this. first one is, again, remember, these are four year-olds. They’re just how to count. But unconsciously, they’re doing these quite calculations that will give them a conditional probability measure. the other interesting thing is that they’re using that evidence to get to an idea, get to a 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 are better at finding out an unlikely hypothesis than adults when we give them exactly the same task. So these circumstances, the children are using statistics to find out about the world, but all, scientists 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 bunch of interesting recently that have shown this playing around is really a kind of research 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 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 hypotheses in the space of two minutes.
(Video) Boy: How about this? Same as the side.
Alison Gopnik: Okay, so 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 recognize that of despair.
(Laughter)
Boy: Oh, it’s because this needs to be like this, and this to be like this.
AG: Okay, hypothesis 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 either.
Boy: Oh, because the light goes only to here, here. Oh, the bottom of this box has electricity here, but this doesn’t have electricity.
AG: Okay, that’s a fourth hypothesis.
Boy: It’s lighting up. So you put four. So you put four on this to make it light up and two on this one to it light up.
AG: Okay,there’s his fifth hypothesis.
Now that is a particularly — is a particularly adorable and articulate little boy, but what discovered is this is actually quite typical. If you at the way children play, when 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 kind of creature? What’s it like to be one of these brilliant butterflies who can test five hypotheses two minutes? Well, if you go back to those psychologists and philosophers, lot of them have said that babies and young children were conscious if they were conscious at all. And I think just opposite is true. I think babies and children are actually more than we are as adults. Now here’s what we about 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 should pay attention it. Our consciousness of that thing that we’re attending to becomes 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 of brains, sends a signal that makes a little part of our brain much more flexible, plastic, better at learning, and shuts down activity in all the rest of our brains. we have a very focused, purpose-driven kind of attention. we look at babies and young children, we see something very different. I think babies and young children to have more of a lantern of consciousness than a spotlight consciousness. So babies and young children are very bad at narrowing 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 in their brains, you see that they’re flooded with these that are really good at inducing learning and plasticity, and the parts haven’t come on yet. So when we say babies and young children are bad at paying attention, what we really is that they’re bad at not 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, kind of consciousness, that we might expect from those butterflies who are to learn.
Well if we want to think about 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 a new situation that we’ve never been in before — 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 seem to more full of consciousness and experience than all the months of being walking, talking, faculty meeting-attending zombie back home. And by the way, that coffee, wonderful coffee you’ve been drinking downstairs, actually mimics the effect of those neurotransmitters. So what’s it like to be a baby? It’s like being in love Paris for the first time after you’ve had three double-espressos. (Laughter) That’s fantastic way to 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 too much about wonderful babies are. It’s good to be a grownup. We can do things tie our shoelaces and cross the street by ourselves. it makes sense that we put a lot of effort into babies think like adults do. But if what we want is to be like those butterflies, 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)