What is going in this baby’s mind? If you’d asked people this 30 years ago, most people, including psychologists, would have that this baby was irrational, illogical, egocentric — that he couldn’t take the perspective another person or understand cause and effect. In the 20 years, developmental science has completely overturned that picture. So in some ways, we think that baby’s thinking is like the thinking of the most brilliant scientists.
Let give you just one example of this. One thing 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 other baby. After all, one of the things that’s hardest for all of to do is to figure out what other people are thinking and feeling. And the hardest thing of 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 to get. We wanted to know if and young children could understand this really profound thing about people. Now the question is: How could we ask them? Babies, after all, can’t talk, if 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 out that the secret was broccoli. What we did — Betty Rapacholi, 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) then what Betty did was to take a little of food from each bowl. And she would act as if liked it or she didn’t. So half the time, she as if 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 the and go, “Mmmmm, broccoli. I tasted the broccoli. Mmmmm.” And then she would take a little bit of crackers, and she’d go, “Eww, yuck, crackers. I tasted the crackers. Eww, yuck.” So she’d act as if she wanted was just the opposite of what the babies wanted. We this with 15 and 18 month-old babies. And then she would simply put her hand and say, “Can you give me some?”
So the question is: What would baby give her, what they liked or what she liked? And the thing was that 18 month-old babies, just barely walking talking, would give her the crackers if she liked crackers, but they would give her the broccoli if she liked broccoli. On the other hand, 15 month-olds would stare her for a long time if she acted as if liked the broccoli, like they couldn’t figure this out. But then after they for a long time, they would just give her the crackers, what they thought must like. So there are two really remarkable things this. The first one is that these little 18 month-old babies already discovered this really profound fact about human nature, that we don’t want the same thing. And what’s more, they felt that should actually 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 learned this deep, profound fact about human nature in the three months from they were 15 months old. So children both know more 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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The question 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? mean, after all, if you look at babies superficially, seem pretty useless. And actually in many ways, they’re than useless, because we have to put so much 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 useless babies, it turns out there’s actually an answer. If we look across many, many different species of animals, not just primates, but also including other mammals, birds, even marsupials kangaroos and wombats, it turns out that there’s a relationship between how long a childhood a has and how big their brains are compared to bodies and how smart and flexible they are.
And of the posterbirds for this idea are the birds up there. one side is a New Caledonian crow. And crows other corvidae, ravens, rooks and so forth, are incredibly smart birds. They’re as smart as chimpanzees 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 chickens 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 at doing anything else. Well it turns out that the babies, the New Caledonian crow babies, are fledglings. depend on their moms to drop worms in their little mouths 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 couple months. So childhood is the reason why the crows end up on the cover of Science the chickens end up in the soup pot.
There’s something about that long childhood seems to be connected to knowledge and learning. Well what of explanation could we have for this? Well some animals, like the chicken, seem to be suited to doing just one thing very well. So they to be beautifully suited to pecking grain in one environment. Other creatures, the crows, aren’t very good at doing anything in particular, but they’re extremely good at learning about laws of environments.
And of course, we human beings are way out on the end the distribution like the crows. We have bigger brains relative to our by far than any other animal. We’re smarter, we’re more flexible, we learn more, we survive in more different environments, we migrated cover the world and even go to outer space. And our and children are dependent on us for much longer than the babies of other species. My son is 23. (Laughter) And at least until they’re 23, we’re still those worms into those little open mouths.
All right, why we see this correlation? Well an idea is that that strategy, learning strategy, is an extremely powerful, great strategy for getting in the world, but it has one big disadvantage. And that one big disadvantage is that, until actually do all that learning, you’re going to be helpless. So you don’t want to have the charging at you and be saying to yourself, “A slingshot or maybe a might work. Which would actually be better?” You want to know all that before mastodons actually show up. And the way the evolutions to have 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 do anything. All 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 them to work to do things out there in the world.
So way of thinking about it is that babies and young children like the research and development division of the human species. So they’re the blue sky guys who just have to go out and learn and have good ideas, and we’re and marketing. We have to take all those ideas that we learned we were children and actually put them to use. way of thinking about it is instead of thinking babies and children as being like defective grownups, we should about them as being a different developmental stage of the same species — of like caterpillars and butterflies — except that they’re actually the brilliant butterflies who are around the garden and exploring, and we’re the caterpillars are inching along our narrow, grownup, adult path.
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this is true, if these babies are designed to learn — and evolutionary story would say children are for learning, that’s what they’re — we might expect that they would have really powerful learning mechanisms. And in fact, the baby’s brain to be the most powerful learning computer on the planet. But real computers are actually getting to be a better. And there’s been a revolution in our understanding of machine recently. And it all depends on the ideas of this guy, the Reverend Thomas Bayes, who was a and mathematician in the 18th century. And essentially what did was to provide a mathematical way using probability to characterize, describe, the way that scientists find out about world. So what scientists do is they have a that they think might be likely to start with. They go out and test it the evidence. The evidence makes them change that hypothesis. Then they test that new and so on and so forth. And what Bayes showed a mathematical way that you could do that. And mathematics is at the core of the best machine learning that we have now. And some 10 years ago, I that babies might be doing the same thing.
So if you want to know what’s going on those beautiful brown eyes, I think it actually looks like this. This is Reverend Bayes’s notebook. So I think those babies actually making complicated calculations with conditional probabilities that they’re revising figure 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 about statistics, they look extremely stupid. How could be that children are doing statistics?
So to test this we used a machine that we have the Blicket Detector. This is a box that lights up and music when you put some things on it and not others. And using very simple machine, my lab and others have done dozens of studies just how good babies are at learning about the world. Let me mention one that we did with Tumar Kushner, my student. I showed you this detector, you would be likely to to begin with that the way to make the detector go would be put a block on top of the detector. But actually, this detector works in a bit of a way. Because if you wave a block over the top of detector, something you wouldn’t ever think of to begin with, the detector will actually activate out of three 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 as if the waving is a more effective strategy than the other strategy. So we did just this; gave four year-olds this pattern of evidence, and we just asked them to it go. And sure enough, the four year-olds used the evidence to wave the object on top of detector.
Now there are two things that are really about this. The 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. And the other interesting thing is that they’re using evidence to get to an idea, get to a hypothesis about world, that seems very unlikely to begin with. And studies we’ve just been doing in my lab, similar studies, we’ve show four year-olds are actually better at finding out an unlikely hypothesis than adults when we give them exactly the same task. So in these circumstances, children are using statistics to find out about the world, but after all, scientists also experiments, and we wanted to see if children are doing experiments. When children 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 a kind of experimental research program. Here’s one from Cristine Legare’s lab. What Cristine did was our Blicket Detectors. And what she did was show children that ones made it go and red ones didn’t, and then she showed them an anomaly. And what you’ll 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 hypothesis has just been falsified.
(Laughter)
Boy: This one up, and this one nothing.
AG: Okay, he’s got experimental notebook out.
Boy: What’s making this light up. (Laughter) don’t know.
AG: Every scientist will recognize that expression despair.
(Laughter)
Boy: Oh, it’s because this needs to be like this, and needs to be like 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 it onto the other location. Not working either.
Boy: Oh, because the goes only to here, not here. Oh, the bottom of this box electricity 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 one to make it light up and two on this one to make light up.
AG: Okay,there’s his fifth hypothesis.
Now that is a — that is a particularly adorable and articulate little boy, what 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 year-olds.
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Well, what’s it like to be this kind 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, a lot of have said that babies and young children were barely conscious if they conscious at all. And I think just the opposite is true. think babies and children are actually more conscious than we are as adults. Now here’s we know about how adult consciousness works. And adults’ and consciousness look kind of like a spotlight. So happens for adults is we decide that something’s relevant important, we should pay attention to it. Our consciousness that thing that we’re attending to becomes extremely bright and vivid, everything else sort of goes dark. And we even something about the way the brain does this.
So what happens when pay attention is that the prefrontal cortex, the sort of executive part of our brains, sends signal that makes a little part of our brain 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 think babies and young seem to have more of a lantern of consciousness than a spotlight 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 from of different sources at once. And if you actually look in brains, you see that they’re flooded with these neurotransmitters are really good at inducing learning and plasticity, and the parts haven’t come on yet. So when we say that babies and children are bad at paying attention, what we really is that they’re bad at not paying attention. So they’re at getting rid of all 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 who are designed to learn.
Well if we want think about a 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 in a new that we’ve never been in before — when we in love with someone new, or when we’re in new city for the first time. And what happens is not that our consciousness contracts, it expands, so that three days in Paris seem to be more full of consciousness experience than all the months of being a walking, talking, meeting-attending zombie back home. And by the way, that coffee, wonderful coffee you’ve been drinking downstairs, actually mimics the effect of those baby neurotransmitters. what’s it like to be 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 does tend to you waking up crying at three o’clock in the morning.
(Laughter)
Now it’s good to be grownup. I don’t want to say too much about wonderful babies are. It’s good to be a grownup. We do things like tie our shoelaces and cross the by ourselves. And it makes sense that we put a lot of effort making babies think like adults do. But if what we want is to like those butterflies, to have open-mindedness, open learning, imagination, creativity, innovation, maybe least some of the time we should be getting the adults to start thinking like children.
(Applause)