What is going on in this baby’s mind? you’d asked people this 30 years ago, most people, including psychologists, would have said this baby was irrational, illogical, egocentric — that he couldn’t take the perspective of another person 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 brilliant scientists.
Let me give you just one example of this. thing that this baby could be thinking about, that be going on in his mind, is trying to figure out what’s going on the mind of that 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 thing all is to figure out that what other people think and isn’t actually exactly like what we think and feel. Anyone who’s followed politics can testify to how that is for some people to get. We wanted to know if babies and young children could this really profound thing about other people. Now the is: How could we ask them? Babies, after all, can’t talk, and if ask a three year-old to tell you what he thinks, what you’ll get is beautiful stream of consciousness monologue about ponies and birthdays things like that. So how do we actually ask 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 give babies two bowls of food: one bowl of raw and one bowl of delicious goldfish crackers. Now all the babies, even in Berkley, like the crackers and don’t like the raw broccoli. (Laughter) then what Betty did was to take a little of food from each bowl. And she would act 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 like a and any other sane person. But half the time, what she would do is take little bit of the broccoli and go, “Mmmmm, broccoli. tasted the broccoli. Mmmmm.” And then she would take a little of 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 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 the question is: What would the give her, what they liked or what she liked? And the remarkable thing was 18 month-old babies, just barely walking and talking, would give 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 if she acted as if she liked the broccoli, like couldn’t figure this out. But then after they stared for long time, they would just give her the crackers, what thought everybody must like. So there are two really remarkable things about this. The first is that these little 18 month-old babies have already discovered this really fact about human nature, that we don’t always want same thing. And what’s more, they felt that they should actually do things to help other get what they wanted.
Even more remarkably though, the fact 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 when they were 15 months old. So children both know and learn more than we ever would have thought. And this is one of hundreds and hundreds of studies over the 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 is 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 have to so much time and energy into just keeping them alive. But if we turn evolution for an answer to this puzzle 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 primates, but also including other mammals, birds, even marsupials like kangaroos wombats, it 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 idea are the birds up there. one side is a New Caledonian crow. And crows and corvidae, ravens, rooks and so forth, are incredibly smart birds. They’re smart as chimpanzees in some respects. And this is a bird the cover of science who’s learned how to use a tool get food. On the other hand, we have our the domestic chicken. And chickens and ducks and geese and turkeys are basically as as dumps. So they’re very, very good at pecking for grain, they’re not much good at doing anything else. Well it turns out the babies, the New Caledonian crow babies, are fledglings. They depend on their to drop worms in their little open mouths for as as two years, which is a really long time in life of a bird. Whereas the chickens are actually mature within a couple months. So childhood is the reason why the crows end up the cover of Science and the chickens end up in soup pot.
There’s something about that long childhood that seems to connected to knowledge and learning. Well what kind of explanation we have 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 pecking grain in one environment. Other creatures, like the crows, aren’t very good at anything in particular, but they’re extremely good at learning about laws of environments.
And of course, we human beings 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 cover the world and even go to outer space. And our babies and children dependent on us for much longer than the babies of other species. My son is 23. (Laughter) And at least they’re 23, we’re still popping those worms into those little open mouths.
All right, would we see this correlation? Well an idea is that that strategy, that strategy, is an extremely powerful, great strategy for getting on in the world, but has one big disadvantage. And that one big disadvantage is that, until actually do all that learning, you’re going to be helpless. you don’t want to have the mastodon charging at you be saying to yourself, “A slingshot or maybe a 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 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. And then as adults, can take all those things that we learned when we babies and children and actually put them to work to things out there in the world.
So one way thinking about it is that babies and young children are like the research and development division of the species. So they’re the protected blue sky guys who just to go out and learn and have good ideas, and we’re production and marketing. We have take 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 children as like defective grownups, we should think about them as being different developmental stage of the same species — kind 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 — this evolutionary story would say children are for learning, that’s they’re for — we might expect that they would have really powerful learning mechanisms. in fact, the baby’s brain seems to be the most powerful computer on the planet. But real computers are actually getting to be a lot better. there’s been a revolution in our understanding of machine learning recently. And it all depends the ideas of this guy, the Reverend Thomas Bayes, who was a and mathematician in the 18th century. And essentially what Bayes was to provide a mathematical way using probability theory to characterize, describe, the way scientists find out about the world. So what scientists do is they have a that they think might be likely to start with. They go out and it against the evidence. The evidence makes them change that hypothesis. Then test that new hypothesis and so on and so forth. And Bayes showed was a mathematical way that you could that. And that mathematics is at the core of the best machine learning that we have now. And some 10 years ago, suggested that babies might be doing the same thing.
So you want to know what’s going on underneath those beautiful brown eyes, I think actually looks something like this. This is Reverend Bayes’s notebook. So 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 taller order to actually demonstrate. Because after all, if you ask even grownups about statistics, they look stupid. How could it be that children are doing statistics?
So to test we used a machine that we have called the Blicket Detector. is a box that lights up and plays music you put some things on it and not others. using this very simple machine, my lab and others have done dozens studies showing just how good babies are at learning the world. Let me mention just one that we with Tumar Kushner, my student. If I showed you this detector, you would be likely to to begin with that the way to make the go would be to put a block on top the detector. But actually, this detector works in a bit of a way. Because if you wave a block over the of the detector, something you wouldn’t ever think of to with, the detector will actually activate two out of three times. Whereas, you do the likely thing, put the block on the detector, it will activate two out of six times. So the unlikely hypothesis has stronger evidence. It looks as if the waving is a more effective than the other strategy. So we did just this; we four year-olds this pattern of evidence, and we just asked them make it go. And sure enough, the four year-olds used the evidence to wave the object on of the detector.
Now there are two things that are really about this. The first one is, again, remember, these four year-olds. They’re just learning how to count. But unconsciously, they’re doing these quite complicated that will give them a conditional probability measure. And the other interesting thing that they’re using that evidence to get to an idea, to a hypothesis about the world, that seems very to begin with. And in studies we’ve just been doing in my lab, similar studies, we’ve show that 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 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 we call it “getting into everything” or else “playing.”
And there’s a bunch 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 Cristine did was use our Detectors. And what she did was show children that yellow made it go and red ones didn’t, and then showed them an anomaly. And what you’ll see is 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 first hypothesis has just been falsified.
(Laughter)
Boy: This one 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 scientist will recognize 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 is his next idea. He told the experimenter to do this, try putting it out onto the other location. Not either.
Boy: Oh, because the light goes only to here, not here. Oh, bottom of this box has electricity in here, but this doesn’t electricity.
AG: Okay, that’s a fourth hypothesis.
Boy: It’s lighting up. So when you put four. So you four on this one to make it light up two on this one to make it light up.
AG: Okay,there’s his fifth hypothesis.
Now that is particularly — that is a particularly adorable and articulate little boy, but Cristine discovered is this is actually quite typical. If you look at the way children play, you ask them to explain something, what they really is do a series of experiments. This is actually typical of four year-olds.
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Well, what’s it like to be kind of creature? What’s it like to be one of these brilliant butterflies can test five hypotheses in two minutes? Well, if you go back to those psychologists philosophers, a lot of them have said that babies and 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 are as adults. Now here’s what we know about how adult consciousness works. And adults’ attention and look kind of like a spotlight. So what happens for adults is we decide 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 goes dark. And we even know something about the way the brain does this.
So what happens we pay attention is that the prefrontal cortex, the sort of executive part of our brains, sends a that makes a little part of our brain much flexible, more plastic, better at learning, and shuts down in all the rest of our brains. So we have very focused, purpose-driven kind of attention. If we look at and young children, we see something very different. I think babies and young children seem have more of a lantern of consciousness than a spotlight of consciousness. So babies young children are very bad at narrowing down to just thing. But they’re very good at taking in lots of information 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 good inducing 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 we really mean is they’re bad at not paying attention. So they’re bad at getting rid of all the interesting that could tell them something and just looking at the thing that’s important. That’s the of attention, the kind of consciousness, that we might expect from those who are designed to learn.
Well if we want to think about a way of getting a taste that kind of baby consciousness as adults, I think best thing is think about cases where we’re put a new situation that we’ve never been in before — when fall in love with someone new, or when we’re in new city for the first time. And what happens then is not our consciousness contracts, it expands, so that those three days in Paris seem be more full of consciousness and experience than all the of 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 in Paris for the first time after you’ve had double-espressos. (Laughter) That’s a fantastic way to be, but it does to leave you waking up crying at three o’clock in the morning.
(Laughter)
Now it’s good be a grownup. I don’t want to say too much about how wonderful babies are. It’s to be a grownup. We can do things like tie our shoelaces and cross the street ourselves. And it makes sense that we put a of effort into making babies think like adults do. But what 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 adults to start thinking more like children.
(Applause)