What is going on in baby’s mind? If you’d asked people this 30 years ago, most people, psychologists, would have said that this baby was irrational, illogical, egocentric — that he couldn’t the perspective of another person or understand cause and effect. the last 20 years, developmental science has completely overturned that picture. So in some ways, think that this baby’s thinking is like the thinking of the most brilliant scientists.
Let me give just one example of this. One thing that this baby be thinking about, that could be going on in mind, is trying to figure out what’s going on in the mind of that baby. After all, one of the things that’s hardest for all of us to do is to figure what other people are thinking and feeling. And maybe hardest thing of all is to figure out that other people think and feel isn’t actually exactly like what think and feel. Anyone who’s followed politics can testify to hard that is for some people to get. We wanted to know babies and young children could understand this really profound thing about other people. Now the is: How could we ask them? Babies, after all, can’t talk, and if you ask a year-old to tell you what he thinks, what you’ll is a beautiful stream of consciousness monologue about ponies birthdays and things like that. So how do we ask them the question?
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Well it turns out that the secret was broccoli. What did — Betty Rapacholi, who was one of my students, and I — was actually to the babies two bowls of food: one bowl of broccoli and one bowl of delicious goldfish crackers. Now of the babies, even in Berkley, like the crackers don’t like the raw broccoli. (Laughter) But then what Betty was to take a little taste of food from bowl. And she would act as if she liked it or she didn’t. So half the time, acted as if she liked the crackers and didn’t the broccoli — just like a baby and any sane person. But half the time, what she would do is take a bit of the broccoli and go, “Mmmmm, broccoli. I tasted the broccoli. Mmmmm.” And she would take a little bit of the crackers, and she’d go, “Eww, yuck, crackers. I the crackers. Eww, yuck.” So she’d act as if what she was just the opposite of what the babies wanted. did this with 15 and 18 month-old babies. And then she simply put her hand out and say, “Can you give me some?”
So the question is: What the baby give her, what they liked or what she liked? the remarkable thing was that 18 month-old babies, just barely walking and talking, would give her 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 time if she acted as if she liked the broccoli, like they couldn’t figure this out. then after they stared for a long time, they would just give her crackers, what they thought everybody must like. So there two really remarkable things about this. The first one is that little 18 month-old babies have already discovered this really profound fact about human nature, that we don’t always the same thing. And what’s more, they felt that they should actually do to help other people get what they wanted.
Even remarkably though, the fact that 15 month-olds didn’t do suggests that these 18 month-olds had learned this deep, profound fact about human nature in the three months when they were 15 months old. So children both know more and learn more than ever would have thought. And this is just one of hundreds hundreds of studies over 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 possible for them to learn so much in such a short time? I mean, all, if you look at babies superficially, they seem pretty useless. And in many ways, they’re worse than useless, because we have to so much time and energy into just keeping them alive. But we turn to evolution for an answer to this puzzle of 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 us primates, also including other mammals, birds, even marsupials like kangaroos and wombats, it turns that there’s a relationship between how long a childhood species has and how big their brains are compared to their bodies how smart and flexible they are.
And sort of posterbirds for this idea are the birds up there. On one side is a New Caledonian crow. crows and other corvidae, ravens, rooks and so forth, are incredibly smart birds. They’re as as chimpanzees in some respects. And this is a on the cover of science who’s learned how to a tool to get food. On 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, they’re not much good at doing anything else. Well it turns that the babies, the New Caledonian crow babies, are fledglings. They depend on moms to drop worms in their little open mouths as long as two years, which is a really long time the life of a bird. Whereas the chickens are actually 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 what kind of could we have for this? Well some animals, like the chicken, seem to beautifully suited to doing just one thing very well. So they seem to beautifully suited to pecking grain in one environment. Other creatures, the crows, aren’t very good at doing anything in particular, they’re extremely good at learning about laws of different environments.
And of course, we human are way out on the end of the distribution the crows. We have bigger brains relative to our bodies by than any other animal. We’re smarter, we’re more flexible, we learn more, we survive in more different environments, we migrated to cover the world even go to outer space. And our babies and children are dependent on us for longer than the babies of any other species. My son 23. (Laughter) And at least until they’re 23, we’re popping those worms into those little open mouths.
All right, would we see this correlation? Well an idea is that strategy, that learning strategy, is an extremely powerful, great strategy getting on in the world, but it has one big disadvantage. that 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 charging at you and be saying to yourself, “A slingshot or a spear might work. Which would actually be better?” You want know all that before the mastodons actually show up. the way the evolutions seems to have solved that problem is a kind of division of labor. So the idea is that have this early period when we’re completely protected. We don’t have do anything. All we have to do is learn. And then adults, we can take all those things that we learned when we babies and children and actually put them to work to do out there in the world.
So one way of about it is that babies and young children are like research and development division of the human species. So they’re the protected sky guys who just have to go out and learn and have ideas, and we’re production and marketing. We have to take all ideas that we learned when we were children and put them to use. Another way of thinking about it is instead thinking of babies and children as being like defective grownups, we should think about them as being a different stage of the same species — kind of like caterpillars and butterflies — except that they’re actually brilliant butterflies who are flitting around the garden and exploring, and we’re the who are inching along our narrow, grownup, adult path.
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If this true, if these babies are designed to learn — and evolutionary story would say children are for learning, that’s they’re for — we might expect that they would have powerful learning mechanisms. And in fact, the baby’s brain seems to be the most powerful computer on the planet. But real computers are actually getting be a lot better. And there’s been a revolution 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. essentially what Bayes did was to provide a mathematical way using probability theory to characterize, describe, the that scientists find out about the world. So what scientists is they have a hypothesis that they think might be 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 Bayes showed was mathematical way that you could do that. And that mathematics is at the core of the best learning programs that we have now. And some 10 ago, I suggested that babies might be doing the 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 are actually making complicated with conditional probabilities that they’re revising to figure out how the world works. All right, now might seem like an even taller order to actually demonstrate. Because after all, if ask even grownups about statistics, they look extremely stupid. could it be that children are doing statistics?
So to test this we a machine that we have called the Blicket Detector. This a box that lights up and plays music when put some things on it and not others. And using this simple machine, my lab and others have done dozens of studies showing how good babies are at learning about the world. Let me mention just that we did with Tumar Kushner, my student. If I you this detector, you would be likely to think begin with that the way to make the detector go would be to put a on top of the detector. But actually, this detector works a bit 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 three times. Whereas, if you do the likely thing, put block on the detector, it will only activate two out of six times. So unlikely hypothesis actually has stronger evidence. It looks as if the waving a more effective strategy than the other strategy. So did just this; we 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 on top of the detector.
Now there are two things that are interesting about this. The first one is, again, remember, are four year-olds. They’re just learning how to count. unconsciously, they’re doing these quite complicated calculations that will them a conditional probability measure. And the other interesting is that they’re using that evidence to get to an idea, get a hypothesis about the world, that seems very unlikely to begin with. And in 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 are when we give them exactly the same task. So these circumstances, the children are using statistics to find about the world, but after all, scientists also do experiments, and we wanted to if children are doing experiments. When children do experiments we it “getting into everything” or else “playing.”
And there’s been a of interesting studies recently that have shown this playing around is really kind of experimental research program. Here’s one from Cristine Legare’s lab. What did was use 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. what you’ll see is that this little boy 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 hypothesis has just been falsified.
(Laughter)
Boy: This one up, and this one nothing.
AG: Okay, he’s got his experimental notebook out.
Boy: What’s this light up. (Laughter) I don’t know.
AG: Every scientist will that expression of despair.
(Laughter)
Boy: Oh, it’s because this needs to be like this, this needs to be like this.
AG: Okay, hypothesis 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 onto other location. Not working either.
Boy: Oh, because the 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 up. So when you put four. So you put on this one to make it light up and on this one to make it light up.
AG: Okay,there’s fifth hypothesis.
Now that is a particularly — that a particularly adorable and articulate little boy, but what Cristine discovered is this actually quite typical. If you look at the way play, when you ask them to explain something, what they do is do a series of experiments. This is actually typical of four year-olds.
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Well, what’s it to be this kind of creature? What’s it like 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 them have said that babies and young children were barely conscious if they were conscious at all. And think just the opposite is true. I think babies and children are actually more conscious than we are adults. Now here’s what we know about how adult consciousness works. And adults’ and consciousness look kind of like a spotlight. So what happens adults is we decide that something’s relevant or important, we should attention to it. Our consciousness of that thing that we’re attending to becomes extremely bright and vivid, everything else sort of goes dark. And we even know something about the way brain does this.
So what happens when we pay attention is that prefrontal cortex, the sort of executive part of our brains, sends signal that makes a little part of our brain much more flexible, more plastic, better learning, and shuts down activity in all the rest of our brains. So we have very focused, purpose-driven kind of attention. If we look at babies and young children, we see something different. I think babies and young children seem to 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 in lots of information from lots of different sources at once. And if you actually look their 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 and young children are bad at paying attention, what really mean is that they’re bad at not paying attention. So they’re bad getting rid of all the interesting things that could tell them something and looking at the thing that’s important. That’s the kind of attention, the kind consciousness, that we might expect from those butterflies who designed to learn.
Well if we want to think about a way of a taste of that kind of baby consciousness as adults, I the best thing is think about cases where we’re put in new situation that we’ve never been in before — we fall in love with someone new, or when we’re in a new city for the first time. And happens then is not that 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 a walking, talking, faculty meeting-attending zombie back home. And the way, that coffee, that wonderful coffee you’ve been downstairs, actually mimics 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 three double-espressos. (Laughter) That’s a fantastic way to be, but it does tend leave you waking up crying at three o’clock in the morning.
(Laughter)
Now it’s good to a grownup. I don’t want to say too much about how wonderful are. It’s good to be a grownup. We can do things tie our shoelaces and cross the street by ourselves. And it makes sense that put a lot of effort into making babies think 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 more like children.
(Applause)