What is going on in this baby’s mind? If you’d people this 30 years ago, most people, including psychologists, have said that this baby was irrational, illogical, egocentric — that he couldn’t the perspective of another person or understand cause and effect. In the last 20 years, science has completely overturned that picture. So in some ways, think that this baby’s thinking is like the thinking the most brilliant scientists.
Let me give you just one example of this. One that this baby could be thinking about, that could be on in his mind, is trying to figure out what’s going on 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 that what people think and feel isn’t actually exactly like what think and feel. Anyone who’s followed politics can testify how hard that is for some people to get. We to know if babies and young children could understand this really profound thing about other people. Now question is: How could we ask them? Babies, after all, can’t talk, if you ask a three year-old to tell you what he thinks, what you’ll is a beautiful stream of consciousness monologue about ponies and birthdays and like that. So how do we actually ask them question?
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Well it turns out that the was broccoli. What we did — Betty Rapacholi, who was one of students, and I — was actually to give the babies two bowls of food: one bowl of broccoli and one bowl of delicious goldfish crackers. Now all of the babies, in Berkley, like the crackers and don’t like the broccoli. (Laughter) But then what Betty did was to take little taste of food from each bowl. And she act as if she liked it or she didn’t. So half the time, acted as if she liked the crackers and didn’t like broccoli — 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 the crackers. Eww, yuck.” So she’d act as if what she wanted was the opposite of what the babies wanted. We did with 15 and 18 month-old babies. And then she would simply her hand out and say, “Can you give me some?”
So the 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 and talking, would give 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 stare at her for a long time if she as if she liked the broccoli, like they couldn’t figure this out. But after they stared for a long time, they would give her the crackers, what they thought everybody must like. So are two really remarkable things about this. The first is that these little 18 month-old babies have already discovered really profound fact about human nature, that we don’t always want the same thing. And what’s more, they that they should actually do things to help other get what they wanted.
Even more remarkably though, the fact 15 month-olds didn’t do this suggests that these 18 month-olds had learned this deep, profound fact about human in the three months from when they were 15 months old. So children both more and learn more than we ever would have thought. And is just one of hundreds and hundreds of studies the last 20 years that’s actually demonstrated it.
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question you might ask though is: Why do children learn much? And how is it possible for them to learn so in such a short time? I mean, after all, if you at babies superficially, they seem pretty useless. And actually many ways, they’re worse than useless, because we have to put so much time and energy into just them alive. But if we turn to evolution for an answer to this puzzle of we spend so much time taking care of useless babies, it turns out that there’s actually an answer. If look across many, many different species of animals, not just us primates, also including other mammals, birds, even marsupials like kangaroos wombats, it turns out that there’s a relationship between long a childhood a species has and how big their brains are compared to their bodies and how and flexible they are.
And sort of the posterbirds this idea are the birds up there. On one side is New Caledonian crow. And crows and other corvidae, ravens, and so forth, are incredibly smart birds. They’re as as chimpanzees in some respects. And this is a bird on cover of science who’s learned how to use a tool to food. On the other 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, good at pecking for grain, and they’re not much good at doing anything else. Well it turns that the babies, the New Caledonian crow babies, are fledglings. They depend their moms to drop worms in their little open mouths for as long as two years, is a really long time in the life of a bird. Whereas the chickens actually mature within a couple of months. So childhood is the reason why the crows up on the cover of Science and the chickens up in the soup pot.
There’s something about that long childhood seems to be connected to knowledge and learning. Well kind of explanation could we have for this? Well some animals, like chicken, seem to be beautifully suited to doing just one thing well. So they seem to be beautifully suited to pecking grain one environment. Other creatures, like the crows, aren’t very good doing anything in particular, but they’re extremely good at learning about laws different environments.
And of course, we human beings are way out on the of the distribution like the crows. We have bigger brains relative to bodies by far than any other animal. We’re smarter, we’re flexible, we can learn more, we survive in more different environments, we to cover the world and even go to outer space. And babies and children are dependent on us for much longer than babies of any other species. My son is 23. (Laughter) at least until they’re 23, we’re still popping those worms into those little mouths.
All right, why would we see this correlation? an idea is that that strategy, that learning strategy, an extremely powerful, great strategy for getting on in world, but it has one big disadvantage. And that one disadvantage is that, until you actually do all that learning, you’re going to be helpless. you don’t want to have the mastodon charging at and be saying to yourself, “A slingshot or maybe spear might work. Which would actually 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 early when we’re completely protected. We don’t have to do anything. 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 about is that babies and young children are like the and development 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 to take all those ideas that we learned when we were children and actually them to use. Another way of thinking about it is instead of thinking of babies and as being like defective grownups, we should think about them as a different developmental stage of the same species — kind 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 for learning, that’s what they’re for — we might expect that they would have really powerful mechanisms. And in fact, the baby’s brain seems to the most powerful learning computer on the planet. But computers are actually getting to be a lot better. there’s been a revolution in our understanding of machine recently. And it all depends on the ideas of this guy, the Thomas Bayes, who was a statistician and mathematician in the 18th century. And essentially what Bayes did was provide a mathematical way using probability theory to characterize, describe, way that scientists find out about the world. So scientists do is they have a hypothesis that they think might be likely start with. They go out and test it against evidence. The evidence makes them change that hypothesis. Then test that new 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 the best machine learning programs that we have now. And some 10 years ago, I suggested babies might be doing the same thing.
So if want to know what’s going on underneath those beautiful brown eyes, think it actually looks something like this. This is Bayes’s notebook. So I think those babies are actually complicated calculations with conditional probabilities that they’re revising to figure out how world works. All right, now that might seem like an taller order to actually demonstrate. Because after all, if ask even grownups about statistics, they look extremely stupid. How could it that children are doing statistics?
So to test this we used a machine that have called the Blicket Detector. This is a box that lights and plays music when you put some things on and not others. And using this very simple machine, my lab and others done dozens of studies showing just how good babies are at learning the world. Let me mention just one that we with Tumar Kushner, my student. If I showed you detector, you would be likely to think to begin with that way to make the detector go would be to put a block on top 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 to begin with, the detector will actually activate two out of times. Whereas, if you do the likely thing, put the on the detector, it will only activate two out of times. So the unlikely hypothesis actually has stronger evidence. It looks as if the waving is a more strategy than the other strategy. So we did just this; we gave four year-olds this of evidence, and we just asked them to make it go. sure enough, the four year-olds used the evidence to the object on top of the detector.
Now there are two that are really interesting about this. The first one is, again, remember, are four year-olds. They’re just learning how to count. But unconsciously, they’re these quite complicated calculations that will give them a conditional probability measure. the other interesting thing is that they’re using that evidence to to an idea, get to a hypothesis about the world, that seems very unlikely to begin with. in studies we’ve just been doing in my lab, 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 circumstances, the children are using statistics to find out about the world, after 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 of experimental 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 it go red ones didn’t, and then she showed them an anomaly. And you’ll see is that this little boy will go through hypotheses in the space of two minutes.
(Video) Boy: How about this? Same the other side.
Alison Gopnik: Okay, so his first has just been falsified.
(Laughter)
Boy: This one lighted up, this one nothing.
AG: Okay, he’s got his experimental 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 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 do this, to try putting it onto the other location. Not working either.
Boy: Oh, the light goes only to here, not here. Oh, the bottom of this box has electricity in here, this doesn’t have electricity.
AG: Okay, that’s a fourth hypothesis.
Boy: It’s lighting up. So when you put four. So put 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 is a particularly — that is a particularly adorable and articulate boy, but what Cristine discovered is this is actually quite typical. If you look the way children play, when you ask them to something, what they really do is do a series of experiments. is actually pretty typical of four year-olds.
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Well, what’s it like to be this kind of creature? What’s like to be one of these brilliant butterflies who can test five hypotheses in two minutes? Well, you go back to those psychologists 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 conscious 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 what happens adults is we decide that something’s relevant or important, we pay attention to it. Our consciousness of that thing that we’re attending to becomes extremely and vivid, and everything else sort of goes dark. we even know something about the way the brain does this.
So happens when we pay attention is that the prefrontal cortex, sort of executive part of our brains, sends a signal that a little part of our brain much more flexible, plastic, better at learning, and shuts 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, see something very different. I think babies and young children seem to have more of a lantern consciousness than a spotlight of consciousness. So babies and young children are bad at narrowing down to just one thing. But they’re very good at taking in lots of information lots of different sources at once. And if you look in their brains, you see that they’re flooded these neurotransmitters that are really good at inducing learning and plasticity, and inhibitory parts haven’t come on yet. So when we say that and young children are bad at paying attention, what we mean is that they’re bad at not paying attention. they’re bad at getting rid of all the interesting that could tell them something and just looking at the that’s important. That’s the kind of attention, the kind 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 as adults, I think the best thing is think about cases where we’re in a new situation that we’ve never been in before — when we in love with someone new, or when we’re in a city for the first time. And what happens then is not that our contracts, it expands, so that those three days in Paris seem to more full of consciousness and experience than all 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 Paris for the first time after you’ve had three double-espressos. (Laughter) That’s a fantastic to be, but it does tend to leave you waking up crying at o’clock in the morning.
(Laughter)
Now it’s good to be a grownup. I don’t to say too much about how wonderful babies are. It’s good to a grownup. We can do things like tie our shoelaces cross the street by ourselves. And 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 butterflies, to have open-mindedness, open learning, imagination, creativity, innovation, maybe at least of the time we should be getting the adults to start thinking like children.
(Applause)