What is going in this 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 person or cause and effect. In the last 20 years, developmental 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 that this 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 us to do is to figure out what other are thinking and feeling. And maybe the hardest thing of all is to out that what other people think and feel isn’t actually exactly like what we and feel. Anyone 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 profound thing about people. Now the question is: How could we ask them? Babies, after all, can’t talk, and 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. how do we actually ask them the question?
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Well it out that the secret was broccoli. What we did — Betty Rapacholi, who was one of my students, I — was actually to give the babies two of food: one bowl of raw broccoli and one bowl delicious goldfish crackers. Now all of 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 it or she didn’t. So half time, she acted as if she liked the crackers and didn’t the broccoli — just like a baby and any other sane person. half the time, what she would do is take little bit of the broccoli and go, “Mmmmm, broccoli. I the broccoli. Mmmmm.” And then she would take a little bit the crackers, and she’d go, “Eww, yuck, crackers. I tasted the crackers. Eww, yuck.” she’d act as if what she wanted was just the of what the babies wanted. We did this with 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 what she liked? And the remarkable was that 18 month-old babies, just barely walking and talking, would her the crackers if she liked the crackers, but they give her the broccoli if she liked the broccoli. the other hand, 15 month-olds would stare at her for long time if she acted as if she liked the broccoli, like couldn’t figure this out. But then after they stared for a long time, they just give her the crackers, what they thought everybody must like. So there are two really remarkable things this. The first one is that these little 18 month-old babies have discovered this really profound fact about human nature, that we don’t always want same thing. And what’s more, they felt that they should actually things to help other people get what they wanted.
Even more remarkably though, the fact 15 month-olds didn’t do this suggests that these 18 month-olds had 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 we ever would have thought. And this is just one of hundreds and hundreds of studies the last 20 years that’s actually demonstrated it.
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The question you might though is: Why do children learn so much? And is it possible for them to learn so much in such short time? I mean, after all, if you look 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 into just keeping alive. But if we turn to evolution for an answer this puzzle of why we spend so much time taking care of useless babies, it turns that there’s actually an answer. If we look across many, many species of animals, not just us primates, but also including mammals, birds, even marsupials like kangaroos and wombats, it out that there’s a relationship between how long a childhood a species has how big their brains are compared to their 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 and other corvidae, ravens, and so forth, are incredibly smart birds. They’re as smart as chimpanzees some respects. And this is a bird on the of science who’s learned how to use a tool to get food. On the hand, we have our friend the domestic chicken. And chickens and ducks and geese and turkeys basically as dumb as dumps. So they’re very, very at pecking for grain, and they’re not much good at doing else. Well it turns out 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 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 soup pot.
There’s about that long childhood that seems to be connected knowledge and learning. Well what kind of explanation could we for this? Well some animals, like the chicken, seem to be beautifully suited doing just one thing very well. So they seem to be beautifully suited to pecking in one environment. Other creatures, like the crows, aren’t good at doing anything in particular, but they’re extremely good at learning laws of different environments.
And of course, we human beings are way out on end of the distribution like the crows. We have bigger brains relative to our bodies by than any other animal. We’re smarter, we’re more flexible, can learn 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 than the babies of any other species. My son is 23. (Laughter) at least until they’re 23, we’re still popping those worms those little open mouths.
All right, why would we see this correlation? Well an is that that strategy, that learning strategy, is an extremely powerful, strategy for getting on in the world, but it has one disadvantage. And that one big disadvantage is that, until you actually do all that learning, you’re to be helpless. So you don’t want to have mastodon charging at you and be saying to yourself, “A slingshot or maybe a spear might work. Which would be better?” You want to know all that before the actually 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 period we’re completely protected. We don’t have to do anything. All we to do is learn. And then as adults, we take all those things that we learned when we were and children and actually put them to work to do things out there in the world.
So way of thinking about it is that babies and young children are the research and development division of the human species. So they’re the protected blue sky guys just have to go out and learn and have ideas, and we’re production and marketing. We have to all those ideas that we learned when we were children and actually put them use. Another way of thinking about it is instead of thinking of babies and children as like defective grownups, we should think about them as being different developmental stage of the same species — kind of like caterpillars and — except that they’re actually the brilliant butterflies who flitting around the garden and exploring, and we’re the caterpillars who are inching along narrow, grownup, adult path.
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If this is true, if these babies are designed learn — and this evolutionary story would say children are learning, that’s what they’re for — we might expect they would have really powerful learning mechanisms. And in fact, the baby’s brain seems to be 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 learning recently. And it depends on the ideas of this guy, the Reverend Bayes, who was a statistician and mathematician in the 18th century. And what Bayes did was to provide a mathematical way using theory to characterize, describe, the way that scientists find out about the world. So what scientists is they have a hypothesis that they think might be likely to start with. They go and test it against the evidence. The evidence makes them change hypothesis. Then they test that new hypothesis and so and so forth. And what Bayes showed was a way that you could do that. And that mathematics is the core of the best machine learning programs that we have now. And some 10 years ago, I that babies might be doing the same thing.
So you want to know what’s going on underneath those brown eyes, I think it actually looks something like 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 an even taller 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 used a machine that we have called the Blicket Detector. This is a box that up and plays music when you put some things on and not others. And using this very simple machine, my lab and others have done dozens studies showing just how good babies are at learning about the world. Let me mention just one that did with Tumar Kushner, my student. If I showed you this detector, you would be likely to think begin with that the way to make the detector go would be to a block on top of 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 think of to begin with, the detector will actually activate two of three times. Whereas, if you do the likely thing, put the block the detector, it will only activate two out of six times. So unlikely hypothesis actually has stronger evidence. It looks as the waving is a more effective strategy than the strategy. So we did just this; we gave four year-olds this pattern of evidence, and we just asked to make it go. And sure enough, the four year-olds used the evidence to wave object on top of the detector.
Now there are things that are really interesting about this. The first one is, again, remember, these are year-olds. They’re just learning how to count. But unconsciously, they’re doing these complicated calculations that will give them a conditional probability measure. And the interesting thing 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 studies we’ve been doing in my lab, similar studies, we’ve show that four year-olds are actually better at finding an unlikely hypothesis than adults are when we give them the same task. So in these circumstances, the children are using to find out about the world, but after all, scientists also experiments, and we wanted to see if children are experiments. When children do experiments we call it “getting into everything” else “playing.”
And there’s been a bunch of interesting studies recently that have this playing around is really a kind of experimental research program. Here’s from Cristine Legare’s lab. What Cristine did was use Blicket Detectors. And what she did was show children that yellow ones made 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 in the space two minutes.
(Video) Boy: How about this? Same as other side.
Alison Gopnik: Okay, so his first hypothesis has just falsified.
(Laughter)
Boy: This 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 will recognize 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 next idea. He told the experimenter to do this, to try putting it out onto the location. Not working either.
Boy: Oh, because the light goes to here, not here. Oh, the bottom of this box has electricity here, but this doesn’t have electricity.
AG: Okay, that’s fourth hypothesis.
Boy: It’s lighting up. So when you put four. So you put four on this one make it light up and two on this one to 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 typical. If you look at the way children play, when you ask them to explain something, what they do is do a series of experiments. This is pretty typical of four year-olds.
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Well, what’s it like be 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 those psychologists and philosophers, a lot of them have said that babies young children were barely conscious if they were conscious all. And I think just the opposite is true. think babies and children are actually more conscious than are as adults. Now here’s what we know about 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 should pay to it. Our consciousness of that thing that we’re attending to extremely bright and vivid, and everything else sort of goes dark. And we know something about the way the brain does this.
So what when we pay attention is that the prefrontal cortex, the sort of executive part our brains, sends a signal that makes a little part of our brain much flexible, more plastic, better at learning, and shuts down activity in the rest of our brains. So we have a very focused, purpose-driven kind of attention. If we look babies and young children, we see something very different. think babies and young children seem to have more of a lantern of consciousness 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 lots of information from lots of different sources at once. if you actually look in their brains, you see they’re flooded with these neurotransmitters that are really good at learning and plasticity, and the inhibitory parts haven’t come yet. So when we say that babies and young children are at paying attention, what we really mean is that they’re bad at paying attention. So they’re bad at getting rid of the interesting things that could tell them something and looking at the thing that’s important. That’s the kind attention, the kind of consciousness, that we might expect from those who are designed to learn.
Well if we want to think a way of getting a taste of that kind of baby consciousness adults, I think the best thing is think about cases where we’re put in a new that we’ve never been in before — when we fall in love with someone new, or when we’re a new city for the first time. And what happens is not that our consciousness contracts, it expands, so that those three days in Paris seem be more full of consciousness and experience than all the months of being a walking, talking, meeting-attending zombie back home. And by the way, that coffee, that coffee you’ve been drinking downstairs, actually mimics the effect of baby neurotransmitters. So what’s it like to be a baby? It’s like being love in Paris for the first time after you’ve had 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 babies are. It’s good to be a grownup. We can do things tie our shoelaces and cross the street by ourselves. it makes sense that we put a lot of effort into making babies think like do. But if what we want is to be like butterflies, to have open-mindedness, open learning, imagination, creativity, innovation, maybe at some of the time we should be getting the adults to thinking more like children.
(Applause)