What is going on in baby’s mind? If you’d asked people this 30 years ago, people, including psychologists, would have said that this baby irrational, illogical, egocentric — that he couldn’t take the perspective of another or understand cause and effect. In the last 20 years, developmental science has completely overturned that picture. in some ways, we think that this baby’s thinking is the thinking of the most brilliant scientists.
Let me you just one example of this. One thing that this baby could be thinking about, that be going on in his mind, is trying to figure out what’s on in the mind of that other baby. After all, one the things that’s hardest for all of us to is to figure out what other people are thinking feeling. And maybe the hardest thing of all is to out that what other people think and feel isn’t actually exactly like we think and feel. Anyone who’s followed politics can testify to hard that is for some people to get. We wanted to know if babies and young 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 three year-old to you what he thinks, what you’ll get is a beautiful stream consciousness monologue about ponies and birthdays and things like that. So how do we actually them the question?
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Well it turns out that the secret was broccoli. What we did — Rapacholi, who was one of my students, and I — was to give the babies two bowls of food: one of raw broccoli and one bowl of delicious goldfish crackers. Now all the babies, even in Berkley, like the crackers and don’t like raw broccoli. (Laughter) But then what Betty did was to take a little taste of food each bowl. And she would act as if she liked or she didn’t. So half the time, she acted as if she liked crackers and didn’t like the broccoli — just like a baby and any other sane person. But half time, what she would do is take a little bit the broccoli and go, “Mmmmm, broccoli. I tasted the broccoli. Mmmmm.” And then she would take little bit of the crackers, and she’d go, “Eww, yuck, crackers. tasted the crackers. Eww, yuck.” So she’d act as if what she was just the opposite of what the babies wanted. We did this 15 and 18 month-old babies. And then she would simply put 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, they would give her the broccoli if she liked the broccoli. On the other hand, 15 month-olds would at her for a long time if she acted as if liked the broccoli, like they couldn’t figure this out. But then they stared for a long time, they would just give the crackers, what they thought everybody must like. So are two really remarkable things about this. The first one is these little 18 month-old babies have already discovered this really profound about human nature, that we don’t always want the same thing. what’s more, they felt that they should actually do things to other people get what they wanted.
Even more remarkably though, 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 when they 15 months old. So children both know more and learn more than we ever would have thought. this is just one of hundreds and hundreds of studies over the last 20 years that’s actually it.
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The question you might ask though is: Why do children learn much? And how is it possible for them to learn so much in a short time? I mean, after all, if you look at superficially, they seem pretty useless. And actually in many ways, they’re than useless, because we have to put so much time and energy just keeping them alive. But if we turn to for an answer to this puzzle of why we so much time taking care of useless babies, it turns out that there’s actually answer. If we look across many, many different species of animals, not just primates, but also including other mammals, birds, even marsupials like kangaroos wombats, it turns out that 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 they are.
And sort of the posterbirds for this idea are the up there. On one side is a New Caledonian crow. And crows other corvidae, ravens, rooks and so forth, are incredibly birds. They’re as smart as chimpanzees in some respects. And is a bird on the cover of 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 as dumps. So they’re very, very good at 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 on moms to drop worms in their little open mouths for 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 end on the cover of Science and the chickens end up in the pot.
There’s something about that long childhood that seems to be connected to and learning. Well what kind of explanation could we have this? Well some animals, like the chicken, seem to be 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 out on the end the distribution like the crows. We have bigger brains to our bodies by far than any other animal. We’re smarter, we’re more flexible, we can learn more, survive in more different environments, we migrated to cover the world and even go to space. And our babies and children are dependent on for much longer than the babies of any other species. My is 23. (Laughter) And at least until they’re 23, we’re still those worms into those little open mouths.
All right, why would we see this correlation? Well an idea that that strategy, that learning strategy, is an extremely powerful, great strategy for on 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 to have the mastodon charging at you and be saying yourself, “A slingshot or maybe a spear might work. Which would actually be better?” You want know all that before the mastodons actually show up. And 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 were babies children and actually put them to work to do things out in the world.
So one way of thinking about it that babies and young children are like the research and development division of the human species. So they’re protected blue sky guys who just have to go out and learn and have good ideas, we’re production and marketing. We have to take all those ideas that we learned when we children and actually put them to use. Another way 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 of like caterpillars and butterflies — that they’re actually the brilliant butterflies who are flitting around garden and exploring, and we’re the caterpillars who are inching along our narrow, grownup, path.
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If this is true, if these babies are designed to learn — and this evolutionary would say children are for learning, that’s what they’re — we might expect that they would have really learning mechanisms. And in fact, the baby’s brain seems to be the most powerful learning on the planet. But real computers are actually getting to be lot better. And there’s been a revolution in our understanding machine learning recently. And it all depends on the of this guy, the Reverend Thomas Bayes, who was statistician and mathematician in the 18th century. And essentially 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 do is they have hypothesis that they think might be likely to start with. go out and test it against the evidence. The evidence them change that hypothesis. Then they test that new hypothesis and so and so forth. And what Bayes showed was a mathematical way that you could that. And that mathematics is at the core of best machine learning programs that we have now. And 10 years ago, I suggested that babies might be doing same thing.
So if you 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. I think those babies are actually making complicated calculations with probabilities that they’re revising to figure out how the works. All right, now that might seem like an even order to actually demonstrate. Because after all, if you ask even about statistics, they look extremely stupid. How could it that children are doing statistics?
So to test this we used a machine we have called the Blicket Detector. This is a box that up and plays music when you put some things it and not others. And using this very simple machine, lab and others have done dozens of studies showing just how good babies at learning about the world. Let me mention just one that did with Tumar Kushner, my student. If I showed this detector, you would be likely to think to begin with that the to make the detector go would be to put a block on top of the detector. actually, this detector works in a bit of a strange way. Because you wave a block over the top of the detector, something you wouldn’t ever think to begin with, the detector will actually activate two of three times. Whereas, if you do the likely thing, the block on the detector, it will only activate out of six times. So the unlikely hypothesis actually has evidence. It looks as if the waving is a more strategy than the other strategy. So we did just this; we gave year-olds this pattern of evidence, and we just asked them to make it go. And sure enough, four year-olds used the evidence to wave the object on top of detector.
Now there are two things that are really interesting about this. The one is, again, remember, these are four year-olds. They’re just how to count. But unconsciously, they’re doing these quite complicated calculations will give them a conditional probability measure. And the other interesting thing that they’re using that evidence to get to an idea, get to a hypothesis about the world, that very unlikely to begin with. And 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 than adults are when we give them exactly the same task. in these circumstances, the children are using statistics to find out about the world, after all, scientists also do experiments, and we wanted see if children are doing experiments. When children do experiments we call “getting into everything” or else “playing.”
And there’s been a bunch of studies recently that have shown this playing around is 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 made it go and red ones didn’t, and then she showed an anomaly. And what you’ll see is that this little boy will go five hypotheses in the space of two minutes.
(Video) Boy: about this? Same as the other side.
Alison Gopnik: Okay, his first hypothesis has just been falsified.
(Laughter)
Boy: one lighted up, and this one nothing.
AG: Okay, he’s his experimental notebook 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 be like this, and needs to be like this.
AG: Okay, hypothesis two.
Boy: That’s why. Oh.
(Laughter)
AG: Now is his next idea. He told the experimenter to do this, 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 in here, 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 this one make it light up and two on this one to make it light up.
AG: Okay,there’s his hypothesis.
Now that is a particularly — that is a particularly adorable articulate little boy, but what Cristine discovered is this is actually typical. If you look at the way children play, you ask them to explain something, what they really do do a series of experiments. This is actually pretty typical four year-olds.
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Well, what’s it like to be this kind of creature? What’s it to be one of these brilliant butterflies who can test five hypotheses two minutes? Well, if you go back to those psychologists philosophers, a lot of them have said that babies 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 we are as adults. Now here’s what we know about how adult works. And adults’ attention and consciousness look kind of like a spotlight. what happens for adults is we decide that something’s relevant or important, we should attention to it. Our consciousness of that thing that we’re to becomes extremely bright and vivid, and everything else of goes dark. And we even know something about the the brain does this.
So what happens when we attention is that the prefrontal cortex, the sort of executive of our brains, sends a signal that makes a little part our brain 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 attention. If we look at babies and young children, we something very 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 narrowing down to just one thing. But they’re very at taking 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 that are really at inducing learning and plasticity, and the inhibitory parts haven’t come yet. So when we say that babies and young are bad at paying attention, what we really mean 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 of consciousness, that we might expect from those butterflies who are designed learn.
Well if we want to think about a way of getting a taste of that kind of consciousness as adults, I think the best thing is think about where we’re put in a new situation that we’ve never in before — when we fall in love with new, or when we’re in a new city for the first time. And what 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 being a walking, talking, faculty meeting-attending zombie back home. by the way, that coffee, that wonderful coffee you’ve 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 leave you waking up crying at three o’clock in the morning.
(Laughter)
Now it’s to be a grownup. I don’t want to say too much how wonderful babies are. It’s good to be a grownup. can do things like tie our shoelaces and cross street by ourselves. And it makes sense that we put a lot effort into making babies think like adults do. But if we want is to be like those butterflies, to have open-mindedness, learning, imagination, creativity, innovation, maybe at least some of the time we should getting the adults to start thinking more like children.
(Applause)