What is going in this baby’s mind? If you’d asked people this 30 ago, most people, including psychologists, would have said that this was irrational, illogical, egocentric — that he couldn’t take the of another person or understand cause and effect. In the last 20 years, developmental science has completely that picture. So in some ways, we think that this baby’s thinking is like the of the most brilliant scientists.
Let me give you 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 other baby. After all, one of the things that’s hardest for of us to do is to figure out what people are thinking and feeling. And maybe the hardest of all is to figure 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 and young children could understand this really profound thing about other people. Now the question is: How 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 consciousness monologue about and birthdays and things like that. So how do we ask them the question?
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Well it turns 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 bowl of raw and one bowl of delicious goldfish crackers. Now all of the babies, even in Berkley, like the and don’t like the raw broccoli. (Laughter) But then what Betty did to take a little taste of food from each bowl. And would act as if she liked it or she didn’t. So half the time, she acted as if she the crackers and didn’t like the broccoli — just a baby and any other sane person. But half the time, what she do is take a little bit of the broccoli and go, “Mmmmm, broccoli. I tasted broccoli. Mmmmm.” And then she would take a little 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 would simply her hand out and say, “Can you give me some?”
So the question is: What would 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 the crackers if she liked the crackers, but they would give her the if 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 couldn’t figure this out. But then after they stared a long time, they would just give her the crackers, what they thought must like. So there are two really remarkable things about this. The first one that these little 18 month-old babies have already discovered really profound fact about human nature, that we don’t always want the same thing. And what’s more, felt that they should actually do things to help people get what 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 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 and hundreds of over the last 20 years that’s actually demonstrated it.
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The you might ask though is: Why do children learn so much? And how it possible for them to learn so much in such short time? I mean, after all, if you look at babies superficially, they seem pretty useless. actually in many ways, they’re worse than useless, because we to put so much time and energy into just keeping alive. But if we turn to evolution for an answer to this of why we spend so much time taking care useless babies, it turns out that there’s actually an answer. we look across many, many different species of animals, not just us primates, but also other mammals, birds, even marsupials like kangaroos and wombats, it turns out that there’s a between how long a childhood a species has and big their brains are compared to their bodies and smart and flexible they are.
And sort of the posterbirds for this idea are the up there. On one side is a New Caledonian crow. crows and other corvidae, ravens, rooks and so forth, are smart birds. They’re as smart as chimpanzees in some respects. And this is a bird the cover of science who’s learned how to use a tool to get food. On other hand, we have our friend the domestic chicken. And chickens and ducks geese and turkeys are basically as dumb as dumps. So they’re very, good at pecking for grain, and they’re not much at doing anything else. Well it turns out that the babies, New Caledonian crow babies, are fledglings. They depend on their moms to drop worms in their little open for as long as two years, which is a really long time in the life of bird. Whereas the chickens are actually mature within a couple months. So childhood is the reason why the crows end up on cover of Science and the chickens end up in the pot.
There’s something about that long childhood that seems to connected to knowledge and learning. Well what kind of explanation could we for this? Well some animals, like the chicken, seem to beautifully suited to doing just one thing very well. they seem to be beautifully suited to pecking grain one environment. Other creatures, like the crows, aren’t very at doing anything in particular, but they’re extremely good at about laws of different environments.
And of course, we human beings are out on the end of the distribution like the crows. We have bigger brains relative to bodies 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 babies and children are dependent on us much longer than the babies of any other species. My is 23. (Laughter) And 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 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 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. 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 is with a kind of division of labor. So the idea that we have this early period when we’re completely protected. We don’t have do anything. All we have to do is learn. then as adults, we can take all those things that we learned when were babies and children and actually put them to work do things out there in the world.
So one way of thinking about it that babies and young children are like the research and division of the human species. So they’re the protected blue guys who just have to go out and learn and have ideas, and 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 of thinking about it is instead thinking of babies and children as being like defective grownups, we think about them as being a different developmental stage of the same species — kind like caterpillars and butterflies — except that they’re actually the butterflies who are flitting around the garden and exploring, and we’re the caterpillars who are along our narrow, grownup, adult path.
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If this is true, these babies are designed to learn — and this evolutionary story would say children are for learning, that’s they’re for — we might expect that they would really powerful learning mechanisms. And in fact, the baby’s brain seems to be the most learning computer on the planet. But real computers are actually to be a lot better. And there’s been a revolution in our understanding of machine recently. And it all depends on the ideas of guy, the Reverend Thomas Bayes, who was a statistician and mathematician the 18th century. And essentially what Bayes did was to provide mathematical way using probability theory to characterize, describe, the way that scientists find out about world. So what scientists do is they have a hypothesis that they think might be likely start with. They go out and test it against the evidence. The evidence makes them change hypothesis. Then they test that new hypothesis and so on and so forth. And what Bayes showed a mathematical way that you could do 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 the same thing.
So if you want know what’s going on underneath those beautiful brown eyes, I think it actually something like this. This is Reverend Bayes’s notebook. So I think those babies are actually complicated calculations with conditional probabilities that they’re revising to figure how the world works. All right, now that might like an even taller order to actually demonstrate. Because all, if you ask even grownups about statistics, they extremely stupid. How could it be that children are statistics?
So to test this we used a machine that we called the Blicket Detector. This is a box that lights up and plays music when you 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 just one we did with Tumar Kushner, my student. If I showed you this detector, you would likely to think to begin with that the way to make the detector go would to put a block on top of the detector. actually, this detector works in a bit of a strange way. Because if you a block over the top of the detector, something you wouldn’t ever think of to begin with, the will actually activate two out of three times. Whereas, if you the likely thing, put the block on the detector, it will only activate two of 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 make go. And sure enough, the four year-olds used the evidence wave the object on top of the detector.
Now there are two that are really interesting about this. The first one is, again, remember, these are four year-olds. They’re learning how to count. But unconsciously, they’re doing these quite complicated calculations that will give a conditional probability measure. And the other interesting thing that they’re using that evidence to get to an idea, get a hypothesis about the world, that seems very unlikely to begin with. in studies we’ve just been doing in my lab, studies, we’ve show that four year-olds are actually better finding out an unlikely hypothesis than adults are when we them exactly the same task. So in 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 call it “getting into everything” or else “playing.”
And there’s been a bunch interesting studies recently that have shown this playing around is really a kind experimental research program. Here’s one from Cristine Legare’s lab. Cristine did was use our Blicket Detectors. And what she did was children that yellow ones made it go and red didn’t, and then she showed them an anomaly. And what you’ll see is this little boy will go through five hypotheses in space of two minutes.
(Video) Boy: How about this? as the other side.
Alison Gopnik: Okay, so his first hypothesis just been falsified.
(Laughter)
Boy: This one lighted up, and this one nothing.
AG: Okay, he’s got his 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, and this to be like this.
AG: Okay, hypothesis two.
Boy: That’s why. Oh.
(Laughter)
AG: Now this is his next idea. He told the 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 a hypothesis.
Boy: It’s lighting up. So when you put four. you put four on this one to make it up and two on this one to make it light up.
AG: Okay,there’s fifth hypothesis.
Now that is a particularly — that is a particularly adorable and articulate little boy, but Cristine discovered is this is actually quite typical. If you look at way children play, when you ask them to explain something, what they really do is do series of experiments. This is actually 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 of these brilliant butterflies who can test five hypotheses in 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 all. And I think just the opposite is true. I think and children are actually more conscious than we are as adults. here’s what we know about how adult consciousness works. And adults’ and consciousness look kind of like a spotlight. So what happens for adults is decide that something’s relevant or important, we should pay attention to it. Our consciousness of that thing we’re attending 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 the prefrontal cortex, the sort of executive part of brains, sends a signal that makes a little part of our brain much flexible, more plastic, better at learning, and shuts down activity in all the rest of our brains. we have a very focused, purpose-driven kind of attention. If we look at babies young children, we see something very different. I think babies and young children seem to have more of lantern of consciousness than a spotlight of consciousness. So babies and children are very bad at narrowing down to just thing. But they’re very good at taking in lots of information from of different sources at once. And if you actually look in their brains, you see that they’re with these neurotransmitters that are really good at inducing learning and plasticity, and the inhibitory parts haven’t on yet. So when we say that babies and young children are at paying attention, what we really mean is that they’re bad not paying attention. So they’re bad at getting rid all the interesting things that could tell them something just looking at the thing that’s important. That’s the kind of attention, the kind consciousness, that we might expect from those butterflies who are designed to learn.
Well if want to think about a way of getting a taste that 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 never been in — when we fall in love with someone new, or we’re in a new city for the first time. And happens then is not that our consciousness contracts, it expands, that those 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, 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 in love in Paris for the first time after you’ve had three double-espressos. (Laughter) That’s a fantastic way be, but it does tend to leave you waking 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 wonderful babies are. It’s good to be a grownup. We can do things like tie our shoelaces cross the street by ourselves. And it makes sense that we a lot of effort into making babies think like adults do. But if we want is to be like those butterflies, to have open-mindedness, open learning, imagination, creativity, innovation, maybe least some of the time we should be getting the to start thinking more like children.
(Applause)