What is going on in this baby’s mind? you’d asked people this 30 years ago, most people, including psychologists, have said that this baby was irrational, illogical, egocentric — that he couldn’t take the perspective of person or understand cause and effect. In the last 20 years, developmental science completely overturned that picture. So in some ways, we that this baby’s thinking is like the thinking of the most brilliant scientists.
Let give you just one example of this. One thing that baby could be thinking about, that could be going in his 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 us to is to figure out what other people are thinking and feeling. And maybe hardest thing of all is to figure out that what other think and feel isn’t actually exactly like what we think and feel. 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 we ask them? Babies, after all, can’t talk, and if ask a three year-old to tell you what he thinks, you’ll get is a beautiful stream of consciousness monologue about and birthdays and things like that. So how do we actually them the question?
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Well it turns out the secret was broccoli. What we did — Betty Rapacholi, who was one of students, and I — was actually to give the babies two of food: one bowl of raw broccoli and one 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 a little taste of food from 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 and didn’t like the broccoli — just like a baby and any sane person. But 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 would a little bit of the crackers, and she’d go, “Eww, yuck, crackers. tasted the crackers. Eww, yuck.” So she’d act as if what wanted was just the opposite of what the babies wanted. We did this 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 they liked or she liked? And the remarkable thing was that 18 month-old babies, just barely walking and talking, give her the crackers if she liked the crackers, but they would give her the broccoli she liked 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 they couldn’t figure this out. But after they stared for a long time, they would just give her the crackers, what they thought everybody like. So there are two really remarkable things about this. The first one is that little 18 month-old babies have already discovered this really 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 people get they wanted.
Even more remarkably though, the fact that 15 month-olds didn’t do this suggests these 18 month-olds had learned this deep, profound fact human nature in the three months from when they 15 months old. So children both know more and more than we ever would have thought. And this is just of hundreds and hundreds of studies over the 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 it possible for them to learn so much in such a short time? I mean, after all, you look at babies superficially, they seem pretty useless. And actually in ways, they’re worse than useless, because we have to put so much time and energy just keeping them alive. But if we turn to evolution an answer to this puzzle of why we spend so much time taking care of useless babies, turns out that there’s actually an answer. If we look many, many different species of animals, not just us primates, also including other mammals, birds, even marsupials like kangaroos and wombats, turns out that there’s a relationship between how long a a species has and how big their brains are compared to their bodies and how and flexible they are.
And sort of the posterbirds for this are the birds up there. On one side is a Caledonian crow. And crows and other corvidae, ravens, rooks and so forth, are smart birds. They’re as smart as chimpanzees in some respects. And this a bird on the cover of science who’s learned how to use a tool get food. On the other hand, we have our friend the domestic chicken. And 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 doing else. Well it turns out that the babies, the Caledonian crow babies, are fledglings. They depend on their moms to drop worms their little open mouths for as long as two years, which is a really 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 end up the cover of Science and the chickens end up in the soup pot.
There’s something about that long that seems to be connected to knowledge and learning. Well kind of explanation could we have for this? Well some animals, like the chicken, to be beautifully suited to doing just one thing very well. So they seem be beautifully suited to pecking grain in one environment. creatures, like the crows, aren’t very good at doing in particular, but they’re extremely good at learning about of different environments.
And of course, we human beings are way 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 more, we survive in more different environments, we migrated to the world and even go to outer space. And babies and children are dependent on us for much longer than the babies of any other species. My is 23. (Laughter) And at least until they’re 23, we’re popping those worms into those little open mouths.
All right, why we see this correlation? Well an idea is that that strategy, that strategy, is an extremely powerful, great strategy for getting on the world, but it has one big disadvantage. And one big disadvantage is that, until you actually do all that learning, you’re going be helpless. So you don’t want to have the mastodon at you and be saying to yourself, “A slingshot maybe a spear might work. Which would actually be better?” You want to know all before the mastodons actually show up. And the way the evolutions seems to have solved that problem is 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 do anything. All we to do is learn. And then as adults, we can take all those things we learned when we were babies and children and put them to work to do things out there in the world.
So one of thinking about it is that babies and young children like the research and development division of the human species. So they’re the protected blue sky guys who have to go out and learn and have good ideas, and we’re production and marketing. We have to all those ideas that we learned when we were and actually put them to use. Another way of about it is instead of thinking of babies and as being like defective grownups, we should think about them as being a different developmental stage of same species — kind of like caterpillars and butterflies — except that they’re the brilliant butterflies who are flitting around the garden and exploring, we’re the caterpillars who are inching along our narrow, grownup, path.
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If this is true, if these are designed to learn — and this evolutionary story would say are 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 the most powerful learning computer on the planet. But real computers are actually getting to a lot better. And there’s been a revolution in our understanding of machine recently. And it all depends on the ideas of this guy, Reverend Thomas Bayes, who was a statistician and mathematician in the 18th century. And essentially Bayes did was to provide a mathematical way using probability theory characterize, describe, the way that scientists find out about the world. So what scientists do is they have hypothesis 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 new hypothesis and so on and so forth. And what Bayes was a mathematical way that you could do that. that mathematics is at the core of the best machine learning programs that 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 Reverend Bayes’s notebook. So think those babies are actually making complicated calculations with conditional probabilities that they’re to figure out how the world works. All right, now that might seem like even taller order to actually demonstrate. Because after all, if ask even grownups about statistics, they look extremely stupid. How it be that children are doing statistics?
So to this we used a machine that we have called Blicket Detector. This is a box that lights up plays music when you put some things on it and others. And using this 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. If showed you this detector, you would be likely to think to with that the way to make the detector go would be to put a block on top of detector. But actually, this detector works in a bit of a strange way. 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 two out of times. Whereas, if you do the likely thing, put the on the detector, it will only activate two out six times. So the unlikely hypothesis actually has stronger evidence. It as if the waving is a more effective strategy than other strategy. So we did just this; we gave four year-olds pattern of evidence, and we just asked them to it go. And sure enough, the four year-olds used evidence to wave the object on top of the detector.
Now are two things that are really interesting about this. The first is, again, remember, these are four year-olds. They’re just learning to count. But unconsciously, they’re doing these quite complicated calculations that will give a conditional probability measure. And the other interesting thing is that they’re using evidence to get to an idea, get to a about the world, that seems very unlikely to begin with. in studies we’ve just been doing in my lab, similar studies, we’ve that four year-olds are actually better at finding out an unlikely hypothesis than adults are when give them exactly the same task. So in these circumstances, the children are using statistics find out about the world, but after all, scientists do experiments, and we wanted to see if children are experiments. When children do experiments we call it “getting into everything” or “playing.”
And there’s been a bunch of interesting studies recently that have shown this playing is really a kind of experimental research program. Here’s one from Cristine Legare’s lab. Cristine did was use our Blicket Detectors. And what she did was show children that yellow ones made go and red ones didn’t, and then she showed them anomaly. And what you’ll see is that this little will go through five hypotheses in the space of minutes.
(Video) Boy: How about this? Same as the other side.
Alison Gopnik: Okay, so his first hypothesis just been falsified.
(Laughter)
Boy: This one lighted up, and one nothing.
AG: Okay, he’s got his experimental notebook out.
Boy: What’s making light up. (Laughter) I don’t know.
AG: Every scientist recognize that expression of despair.
(Laughter)
Boy: Oh, it’s because needs to be like this, and this needs to be like this.
AG: Okay, two.
Boy: That’s why. Oh.
(Laughter)
AG: Now this is his next idea. He the experimenter to do this, to try putting it out the other location. Not working either.
Boy: Oh, because the light goes only 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. when you put four. So you put four on one to make it light up and two on this one make it light up.
AG: Okay,there’s his fifth hypothesis.
Now is a particularly — that is a particularly adorable articulate little boy, but what Cristine discovered is this is actually quite typical. If you at the way children play, when you ask them to something, what they really do is do a series of experiments. This actually pretty typical of four year-olds.
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Well, what’s it like to this kind of creature? What’s it like to be one of these brilliant who can test 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 conscious at all. And I think just the is true. I think babies and children are actually conscious than we are as adults. Now here’s what know about how adult consciousness works. And adults’ attention and look kind of like a spotlight. So what happens for is we decide that something’s relevant or important, we should pay to it. Our consciousness of that thing that we’re to becomes extremely bright and vivid, and everything else sort of goes dark. And even know something about the way the brain does this.
So what happens when we pay attention is that prefrontal cortex, the sort of executive part of our brains, sends a signal that makes little part of our brain much more flexible, more plastic, at learning, and shuts down activity in all the rest of brains. So we have a very focused, purpose-driven kind attention. If we look at babies and young children, we see something very different. think babies and young children seem to have more a lantern of consciousness than a spotlight of consciousness. So babies and young children are very at narrowing down to just one thing. But they’re very at taking in lots of information from lots of different sources once. And if you actually look in their brains, you that they’re flooded with these neurotransmitters that are really good at learning and plasticity, and the inhibitory parts haven’t come on yet. So when we say that and young children are bad at paying attention, what really mean is that they’re bad at not paying attention. So they’re bad at getting rid all the interesting things that could tell them something and just looking the thing that’s important. That’s the kind of attention, the kind of consciousness, that we might expect those butterflies who are designed to learn.
Well if we want think about a way of getting a taste of kind of baby consciousness as adults, I think the best thing is think about where we’re put in a new situation that we’ve been in before — when we fall in love someone new, or when we’re in a new city for the time. And what happens then is not that our consciousness contracts, it expands, so that those three in Paris seem to be more full of consciousness and experience than all the of being a 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 those baby neurotransmitters. So what’s it like to be baby? It’s like being in love in Paris for the first after you’ve had three double-espressos. (Laughter) That’s a fantastic way to be, it does tend to leave you waking up crying at three o’clock in morning.
(Laughter)
Now it’s good to be a grownup. I don’t want to say much about how wonderful babies are. It’s good to be 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 those butterflies, to open-mindedness, open learning, imagination, creativity, innovation, maybe at least of the time we should be getting the adults to start thinking more children.
(Applause)