What is on in this baby’s mind? If you’d asked people 30 years ago, most people, including psychologists, would have that this baby was irrational, illogical, egocentric — that couldn’t take the perspective of another person or understand and effect. In the last 20 years, developmental science has completely overturned that picture. So some ways, we think that this baby’s thinking is like the thinking of the brilliant scientists.
Let me give you just one example this. One thing that this baby could be thinking about, that could be going in his mind, is trying to figure out what’s going on in mind of that other baby. After all, one of the things that’s hardest for of us to do is to figure out what other people are and feeling. And maybe the hardest thing of all is to figure 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 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 question is: How could we them? Babies, after all, can’t talk, and if you ask a three year-old tell you what he thinks, what you’ll get is a beautiful stream of consciousness about ponies and birthdays and things like that. So how we actually ask them the question?
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Well turns out that the secret was broccoli. What we did — Betty Rapacholi, who was one my students, and I — was actually to give the babies two bowls food: one bowl of raw broccoli and one bowl of 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 from 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 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 of the broccoli and go, “Mmmmm, broccoli. I tasted broccoli. Mmmmm.” And then she would take a little bit the crackers, and she’d go, “Eww, yuck, crackers. I tasted crackers. Eww, yuck.” So she’d act as if what she wanted just the opposite of what the babies wanted. We did this with 15 and 18 month-old babies. And she would simply put her hand out and say, “Can you give some?”
So the question is: What would the baby give her, what they or what she liked? And the remarkable thing was that 18 month-old babies, barely walking and talking, would give her the crackers she liked the crackers, but they would give her the if she liked the broccoli. On the other hand, 15 month-olds stare 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 her the crackers, what they everybody must like. So there are two really remarkable things about this. The first one that these little 18 month-old babies have already discovered this 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 more remarkably though, the fact that 15 month-olds didn’t this suggests that these 18 month-olds had learned this deep, fact about human nature in the three months from when they were 15 months old. So children know more and learn more than we ever would have thought. And this just one of hundreds and hundreds of studies over last 20 years that’s actually demonstrated it.
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question you might ask though is: Why do children so much? And how is it possible for them to so much in such a short time? I mean, after all, you look at babies superficially, they seem pretty useless. And actually in many ways, they’re worse than useless, we have to put so much time and energy just keeping them alive. But if we turn to evolution an answer to this puzzle of why we spend so time taking care of useless babies, it turns out that there’s an answer. If we look across many, many different species of animals, not just us primates, but including other mammals, birds, even marsupials like kangaroos and wombats, it turns out that there’s relationship between how long a childhood a species has and how their brains are compared to their bodies and how smart and flexible they are.
And sort of posterbirds for this idea are the birds up there. On one side a New Caledonian crow. And 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 on the cover of 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 geese and turkeys are basically as dumb as dumps. they’re very, very good at pecking for grain, and they’re not good at doing anything else. Well it turns out that babies, the New Caledonian crow babies, are fledglings. They depend their moms to drop worms in their little open mouths for as long two years, which is a really long time in the life a bird. Whereas the chickens are actually mature within a of months. So childhood is the reason why the crows end on the cover of Science and the chickens end up the soup pot.
There’s something about that long childhood seems to be connected to 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 to pecking grain in one environment. Other creatures, like the crows, aren’t very good doing anything in particular, but they’re extremely good at learning about laws of different environments.
And of course, human beings are way out on the end of the distribution the crows. We have bigger brains relative to our by far than any other animal. We’re smarter, we’re more flexible, we can learn more, we in more different environments, we migrated to cover the 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 son is 23. (Laughter) And at least they’re 23, we’re still popping those worms into those little open mouths.
All right, why we see this correlation? Well an idea is that that strategy, that learning strategy, an extremely powerful, great strategy for getting on in world, but it has one big disadvantage. And that big disadvantage is that, until you actually do all that learning, you’re to be helpless. So you don’t want to have the mastodon charging at you and be to yourself, “A slingshot or maybe a spear might work. Which would actually be better?” want to know all that before the mastodons actually up. And the way the evolutions seems to have solved problem 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 to do anything. All we have do is learn. And then as adults, we can all those things that we learned when we were and children and actually put them to work to do things there in the world.
So one way of thinking 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 to take all those ideas that we learned when we were children and actually put to use. Another way of thinking about it is instead of thinking of and children as being like defective grownups, we should about them as being a different developmental stage of the species — kind of like caterpillars and butterflies — that they’re actually the brilliant butterflies who are flitting the garden and exploring, and we’re the caterpillars who are inching 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 what they’re — we might expect that they would have really powerful learning mechanisms. And in fact, baby’s brain seems to be the most powerful learning computer the planet. But real computers are actually getting to a lot better. And there’s been a revolution in understanding of machine learning recently. And it all depends on the ideas of this guy, the Reverend Bayes, who was a statistician and mathematician in the 18th century. And essentially what Bayes did to provide a mathematical way using probability theory to characterize, describe, the way scientists find out about the world. So what scientists do is have a hypothesis that they think might be likely to start with. They go out test it against the evidence. The evidence makes them change that hypothesis. Then they test that hypothesis and so on and so forth. And what showed was a mathematical way that you could do that. And mathematics is at the core of the best machine learning that we have now. And some 10 years ago, I that babies might be doing the same thing.
So if you want to what’s going on underneath those beautiful brown eyes, I it actually looks something like this. This is Reverend Bayes’s notebook. So I think those are actually making complicated calculations with conditional probabilities that they’re to figure out how the world works. All right, that might seem like an even taller order to actually demonstrate. Because after all, if you ask even about statistics, they look extremely stupid. How could it be that children doing statistics?
So to test this we used a machine that have called the Blicket Detector. This is a box that lights up plays music when you put some things on it and others. And using this very simple machine, my lab others have done dozens of studies showing just how good babies are at learning about world. Let me mention just one that we did Tumar Kushner, my student. If I showed you this detector, would be likely to think to begin with that the way to make detector go would be to put a block on top the detector. But actually, this detector works in a bit of strange way. Because if you wave a block over the of the detector, something you wouldn’t ever think of begin with, the detector will actually activate two out of times. Whereas, if you do the likely thing, put the on the detector, it will only activate two out of six times. So the unlikely hypothesis actually has evidence. It looks as if the waving is a more effective strategy than other strategy. So we did just this; we gave four year-olds this of evidence, and we just asked them to make it go. And enough, the four year-olds used the evidence to wave object on top 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 quite complicated calculations that will give them a conditional measure. And the other interesting thing is that they’re that evidence to get to an idea, get to a hypothesis about world, that seems very unlikely to begin with. And in studies we’ve just been in my lab, similar studies, we’ve show that four year-olds actually better at finding out an unlikely hypothesis than adults are when give them exactly the same task. So in these circumstances, the children are using to find out about the world, but after all, also do experiments, and we wanted to see if are doing experiments. When children do experiments we call “getting into everything” or else “playing.”
And there’s been a of interesting studies recently that have shown this playing is really a kind of experimental research program. Here’s one Cristine Legare’s lab. What Cristine did was use our Blicket Detectors. And what she did was show that yellow ones made it go and red ones didn’t, then she showed them an anomaly. And what you’ll see that this little boy will go through five hypotheses in the space two 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 out.
Boy: What’s making this light up. (Laughter) I don’t know.
AG: Every scientist will recognize that expression 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: this is his next idea. He told the experimenter do this, to try putting it out onto the location. Not working either.
Boy: Oh, because the light goes only to here, not here. Oh, the 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. you put 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 is a particularly — that is a particularly adorable and little boy, but what Cristine discovered is this is actually quite typical. If look at the way children play, when you ask to explain something, what they really do is do a series of experiments. This is pretty typical of four year-olds.
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Well, what’s it to 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 to those psychologists and philosophers, a lot of them said that babies and young children were barely conscious if were conscious at all. And I think just the opposite is true. I babies and children are actually more conscious than we as adults. Now here’s what we know about how consciousness 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, should pay attention to it. Our consciousness of that thing that we’re to becomes extremely bright and vivid, and everything else sort goes dark. And we even know something about the the brain does this.
So what happens when we pay is that the prefrontal cortex, the sort of executive part our brains, sends a signal that makes a little part of brain much more flexible, more plastic, better at learning, and shuts down activity in all rest of our brains. So 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 children seem to have more of a lantern of consciousness than a of consciousness. So babies and young children are very bad at narrowing down to just thing. But they’re very good at taking in lots information from lots of different sources at once. And you actually look in their brains, you see that they’re with these neurotransmitters that are really good at inducing learning and plasticity, the inhibitory parts haven’t come on yet. So when we say babies and young children are bad at paying attention, what really mean is that they’re bad at not paying attention. they’re bad at getting rid of all the interesting things that could tell them something and just looking the thing that’s important. That’s the kind of attention, kind of consciousness, that we might expect from those butterflies who are to learn.
Well if we want to think about a way 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 situation we’ve never been in before — when we fall in love with new, or when we’re in a new city for the first time. what 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, faculty meeting-attending zombie back home. And the way, that coffee, that wonderful coffee you’ve been drinking downstairs, actually mimics the effect those baby neurotransmitters. So 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 the morning.
(Laughter)
Now it’s good to be a grownup. I don’t 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 street by ourselves. And it makes sense that we put lot of effort into making babies think like adults do. if what we want is to be like those butterflies, have open-mindedness, open learning, imagination, creativity, innovation, maybe at some of the time we should be getting the adults to start more like children.
(Applause)