What is going on in baby’s mind? If you’d asked 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 person or understand cause and effect. In the last 20 years, developmental has completely overturned that picture. So in some ways, we think that this baby’s thinking is like the of the most brilliant scientists.
Let me give you just one example of this. thing that this baby could be thinking about, that be going on in his mind, is trying to out what’s going on in the mind of that other baby. After all, of the things that’s hardest for all of us to do is to out what other people are thinking and feeling. And the hardest thing of all is to figure out what other people think and feel isn’t actually exactly like what we think and feel. Anyone who’s politics can testify to how hard that is for some people to get. wanted to know if babies and young children could this really profound thing about other people. Now the question is: How we ask them? Babies, after all, can’t talk, and if you ask three year-old to tell you what he thinks, what you’ll get is a beautiful stream of consciousness about ponies and birthdays and things like that. So how do we actually ask them question?
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Well it turns out that the secret was broccoli. What did — Betty Rapacholi, who was one of my students, I — was actually to give the babies two bowls 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 Betty did was to take a little taste of 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 sane person. half the time, what she would do is take little 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 tasted crackers. Eww, yuck.” So she’d act as if what she wanted was just opposite of what the babies wanted. We did this with 15 and 18 month-old babies. And she would simply put her hand out and say, “Can you give me some?”
So the is: What would the baby give her, what they liked or she liked? And the remarkable thing was that 18 month-old babies, just barely walking and talking, would give her the if she liked the crackers, but they would give her the broccoli if she the broccoli. On the other hand, 15 month-olds would stare at her for a long time she acted as if she liked the broccoli, like couldn’t figure this out. But then after they stared a long time, they would just give her the crackers, they thought everybody must like. So there 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 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 deep, profound fact about human nature in the three months from when were 15 months old. So children both know more learn more than we ever would have thought. And this just one of hundreds and hundreds of studies over last 20 years that’s actually demonstrated it.
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question you might ask though is: Why do children learn so much? And how is it for them to learn so much in such a short time? I mean, after all, if you look babies superficially, they seem pretty useless. And actually in many ways, they’re worse than useless, we have to put so much time and energy into keeping them alive. But if we turn to evolution an answer to this puzzle of why we spend much time taking care of useless babies, it turns out there’s actually an answer. If we look across many, many different species animals, not just us primates, but also including other mammals, birds, even marsupials like kangaroos and wombats, it turns out there’s a relationship between how long a childhood a species has and big their brains are compared to their bodies and how smart and flexible are.
And sort of the posterbirds for this idea are the up there. On one side is a New Caledonian crow. And crows and other corvidae, ravens, rooks and forth, are incredibly smart birds. They’re as smart as in some respects. And this is a bird on the cover science who’s learned how to use a tool to get food. the other hand, we have our friend the domestic chicken. And and ducks and geese and turkeys are basically as dumb dumps. So they’re very, very good at pecking for grain, and they’re not much good at doing else. Well it turns out that the babies, the New Caledonian crow babies, are fledglings. They on their moms to drop worms in their little open mouths for as as two years, which is a really long time in life of a bird. Whereas the chickens are actually within a couple of months. So childhood is the reason the crows end up on the 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, seem to be suited to doing just one thing very well. So they seem to be beautifully suited to pecking in one environment. Other creatures, like the crows, aren’t very at doing anything in particular, but they’re extremely good at learning about laws different environments.
And of course, we human beings are way on the end of the distribution like the crows. We have brains relative to our bodies by far than any animal. We’re smarter, we’re more flexible, we can learn more, we survive in more environments, we migrated to cover the world and even go to outer space. And our babies and are dependent on us for much longer than the of any other species. My son is 23. (Laughter) And least until they’re 23, we’re still popping those worms into little open mouths.
All right, why would we see this correlation? Well an is that that strategy, that learning strategy, is an extremely powerful, strategy for getting on in the world, but it has one disadvantage. And that one big disadvantage is that, until you actually do all that learning, you’re to be helpless. So 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 know all that before the mastodons actually show up. And the way the evolutions seems have 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 do anything. All we have to do is learn. And as adults, we can take all those things that we learned when we were babies and children actually put them to work to do things out there in the world.
So one way thinking about it is that babies and young children are like research and development division of the human species. So they’re protected blue sky guys who just have to go and 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 is instead of of babies and children as being like defective grownups, should think about them as being a different developmental stage of the same species — of like caterpillars and butterflies — except that they’re actually brilliant butterflies who are flitting around the garden and exploring, and we’re the caterpillars who are inching 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 children are for learning, that’s what they’re — we might expect that they would have really powerful learning mechanisms. in fact, the baby’s brain seems to be the most powerful learning computer on the planet. real computers are actually getting to be a lot better. And there’s been revolution in our understanding of machine learning recently. And it all depends the ideas of this guy, the Reverend Thomas Bayes, who was a statistician 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 out about the world. So what do is they have a hypothesis that they think might 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 showed was a mathematical way that you could do that. And that mathematics is at the core of best machine learning programs that we have now. And some 10 years ago, suggested that babies might be doing the same thing.
So you want to know what’s going on underneath those brown eyes, I think it actually looks something like this. is Reverend Bayes’s notebook. So I think those babies are actually making complicated with conditional probabilities that they’re revising to figure out how world works. All right, now that might seem like an even taller order to actually demonstrate. after all, if you ask even grownups about statistics, they extremely stupid. How could it be that children are doing statistics?
So test this we used a machine that we have called the Blicket Detector. is a box that lights up and plays music when put some things on it and not others. And using this very machine, my lab and others have done dozens of showing just how good babies are at learning about world. Let me mention just one that we did with Tumar Kushner, student. If I showed you this detector, you would be likely to to begin with that the way to make the detector would be to put a block on top of detector. But actually, this detector works in a bit a strange way. Because if you wave a block the top of the detector, something you wouldn’t ever of to begin with, the detector will actually activate two out of three times. Whereas, if do the likely thing, put the block on the detector, it will only activate two out of times. So the unlikely hypothesis actually has stronger evidence. It as if the waving is a more effective strategy than the strategy. So we did just this; we gave four year-olds this pattern evidence, and we just asked them to make it go. And sure enough, the year-olds used the evidence to wave the object on top of the detector.
Now are two things that are really interesting about this. The one is, again, remember, these are four year-olds. They’re just learning how to count. But unconsciously, they’re doing quite complicated calculations that will give them a conditional probability measure. And the other interesting 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 been doing in lab, similar studies, we’ve show that four year-olds are actually better at finding out an unlikely hypothesis adults are when we give them exactly the same task. So in these circumstances, 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 it “getting into everything” or else “playing.”
And there’s a bunch of interesting studies 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. what she did was show children that yellow ones made it go and ones 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? as the other side.
Alison Gopnik: Okay, so his first hypothesis has been falsified.
(Laughter)
Boy: This one lighted up, and this 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 expression 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 his next idea. He told the to do this, to try putting it out onto the other location. Not working either.
Boy: Oh, because light goes only to here, not 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 one to it light up and two on this one to make light up.
AG: Okay,there’s his fifth hypothesis.
Now that is particularly — that is a particularly adorable and articulate little boy, what Cristine discovered is this is actually quite typical. you look at the way children play, when you ask them explain something, what they really do is do a series experiments. This is actually pretty 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 five hypotheses in two minutes? Well, if you go back to those and philosophers, a lot of them have said that and young children were barely conscious if they were at all. And I think just the opposite is true. I babies and children are actually more conscious than we are as adults. Now here’s what we know how adult consciousness works. And adults’ attention and consciousness look kind of a spotlight. So what happens for adults is we that something’s relevant or important, we should pay attention to it. Our consciousness of that thing we’re attending to becomes extremely bright and vivid, and everything sort of goes dark. And we even know something the way the brain does this.
So what happens we pay attention is that the prefrontal cortex, the of executive part of our brains, sends a signal that makes a little part of our much more flexible, more plastic, better at learning, and shuts down in all the rest of our brains. So we have a very focused, purpose-driven kind of attention. we look at babies and young children, we see something very different. I babies and young children seem to have more of a lantern of consciousness a spotlight of consciousness. So babies and young children are very bad at narrowing down just one thing. But they’re very good at taking in lots of information lots of different sources at once. And if you actually look in their brains, you see that they’re with these neurotransmitters that are really good at inducing learning and plasticity, and inhibitory parts haven’t come on yet. So when we say that babies and children 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 interesting things that could tell them something and just looking the thing that’s important. That’s the kind of attention, the of consciousness, that we might expect from those butterflies who designed to learn.
Well if we want to think about a way of getting a taste of that of baby consciousness as adults, I think the best is think about cases where 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 a new city for the first time. And what happens then is not that our consciousness contracts, expands, so that those three days in Paris seem 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 to be a baby? It’s like being in love in Paris for the first time after you’ve had double-espressos. (Laughter) That’s a fantastic way to be, but it does tend leave you waking up crying at three o’clock in morning.
(Laughter)
Now it’s good to be a grownup. I don’t want say too much about how wonderful babies are. It’s to be a grownup. We can do things like tie our and cross the street by ourselves. And it makes that we put a lot of effort into making babies think like adults do. But if what want is to be like those butterflies, to have open-mindedness, open learning, imagination, creativity, innovation, maybe least some of the time we should be getting the to start thinking more like children.
(Applause)