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 was irrational, illogical, — that he 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 in some ways, think that this baby’s thinking is like the thinking the most brilliant scientists.
Let me give you just example of this. One thing that this baby could be thinking about, that could be going on his mind, is trying to figure out what’s going on in the mind of that baby. After all, one of the things that’s hardest all of us to do is to figure out what other people are and feeling. And maybe the hardest thing of all is to figure out that what other people think feel isn’t actually exactly like what we think and feel. Anyone who’s followed politics testify to how hard that is for some people get. We wanted to know if babies and young children could understand this really thing about other people. Now the question is: How we ask them? Babies, after all, can’t talk, and if you ask three year-old to tell you what he thinks, what you’ll get is beautiful stream of consciousness monologue about ponies and birthdays and like that. So how do we actually ask them the question?
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Well turns out that the secret was broccoli. What we did — Rapacholi, who was one of my students, and I — actually to give the babies two bowls of food: bowl of raw broccoli and one bowl of delicious goldfish crackers. Now of the babies, even in Berkley, like the crackers don’t like the raw broccoli. (Laughter) But then what Betty was to take a little taste of food from each bowl. And she would act as if liked it or she didn’t. So half the time, she acted as she liked the crackers and didn’t like the broccoli — like a baby and any other sane person. But half the time, what would do is take a 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.” So she’d as if what she wanted was just the opposite of what the babies wanted. We did with 15 and 18 month-old babies. And then she would simply put her hand and say, “Can you give me some?”
So the 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 and talking, would give her the crackers if she the crackers, but they would give her the broccoli if she liked broccoli. On the other hand, 15 month-olds would stare at her a long time if she acted as if she liked the broccoli, they couldn’t figure this out. But then after they stared for a long time, they just give her the crackers, what they thought everybody like. So there are two really remarkable things about this. first one is that these little 18 month-old babies have discovered this really profound fact about human nature, that don’t always want the same thing. And what’s more, they felt they should actually do things to help other people what they wanted.
Even more remarkably though, the fact 15 month-olds didn’t do this suggests that these 18 month-olds had learned this deep, profound about human nature in the three months from when were 15 months old. So children both know more learn more than we ever would have thought. And this is just one of hundreds hundreds of studies over the last 20 years that’s actually it.
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The question you might ask though is: do children learn so much? And how 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 keeping them alive. But if we turn to evolution for answer to this puzzle of why we spend so much taking care of useless babies, it turns out that there’s actually an answer. If 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 a relationship between long a childhood a species has and how big their brains are compared to bodies and how smart and flexible they are.
And sort the posterbirds for this idea are the birds up there. On one side is a New Caledonian crow. And and other corvidae, ravens, rooks and so forth, are incredibly smart birds. They’re smart as chimpanzees in some respects. And this is a bird on 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 and and turkeys are basically as dumb as dumps. So they’re very, very good at pecking for grain, and they’re not good at doing anything else. Well it turns out that the babies, the New crow babies, are fledglings. They depend on their moms to drop worms in little open mouths for as long as two years, which is a long time in the life of a bird. Whereas chickens are actually mature within a couple of months. childhood is the reason why the crows end up the cover of Science and the chickens end up in the pot.
There’s something about that long childhood that seems to be connected knowledge and learning. Well what kind of explanation could have for this? Well some animals, like the chicken, seem be beautifully suited to doing just one thing very well. So they seem to be beautifully suited to grain in one environment. Other creatures, like the crows, aren’t very at doing anything in particular, but they’re extremely good learning about laws of different environments.
And of course, we beings are way out on the end of the distribution like the crows. We bigger brains relative to our 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 to the world and even go to outer space. And our babies and children are dependent on for much longer than the babies of any other species. My son 23. (Laughter) And at least until they’re 23, we’re popping those worms into 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 big disadvantage. And that big disadvantage is that, until you actually do all that learning, you’re going to helpless. So you don’t want to have the mastodon at you and be saying to yourself, “A slingshot or maybe spear might work. Which would actually be better?” You want to know all that before mastodons actually show up. And the way the evolutions to have 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 have do is learn. And then as adults, we can take all those that we learned when we were babies and children actually put them to work to do things out there in the world.
So one way thinking about it is that babies and young children are like the research 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 to use. Another way of thinking about it is instead thinking of babies and children as being like defective grownups, should think about them as being a different developmental stage the same species — kind of like caterpillars and butterflies — except that they’re actually the brilliant who are flitting around the garden and exploring, and we’re the caterpillars who are inching our narrow, grownup, adult path.
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If this is true, if these babies designed to learn — and this evolutionary story would children are for learning, that’s what they’re for — we might that they would have really powerful learning mechanisms. And 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 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 a mathematical using probability theory to characterize, describe, the way that scientists find out about the world. what scientists do is they have a hypothesis that think might be likely to start with. They go out and test against the evidence. The evidence makes them change that hypothesis. they test that new hypothesis and so on and forth. And what Bayes showed was a mathematical way you could do that. And that mathematics is at the core of best machine learning programs that we have now. And some 10 ago, I suggested that babies might be doing the same thing.
So if 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. 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, you ask even grownups about statistics, they look extremely stupid. could it be that children are doing statistics?
So to test this we used a machine that we called the Blicket Detector. This is a box that lights and plays music when you put some things on it and others. And using this very simple machine, my lab and others have done dozens of studies just how good babies are at learning about the world. me mention just one that we did with Tumar Kushner, student. If I showed you this detector, you would be likely to think to begin with that way to make the detector go would be to put a on top of the detector. But actually, this detector works in a bit of a way. Because if you wave a block over the top of detector, something you wouldn’t ever think of to begin with, the will actually activate two out of three times. Whereas, if you do the likely thing, put block on the detector, it will only activate two out of times. So the unlikely hypothesis actually has stronger evidence. It as if the waving is a more effective strategy than the other strategy. So did just this; we gave four year-olds this pattern of evidence, and we just them to make it go. And sure enough, the four year-olds used the evidence wave the object on top of the detector.
Now are two things that are really interesting about this. first one is, again, remember, these are four year-olds. They’re just how to count. But unconsciously, they’re doing these quite complicated calculations that give them a conditional probability measure. And the other interesting thing is that they’re using that evidence to to an idea, get to a hypothesis about the world, that seems unlikely to begin with. And in studies we’ve just been doing in lab, similar studies, we’ve show that four year-olds are better at finding out an unlikely hypothesis than adults when we give them exactly the same task. So in circumstances, the children are using statistics to find out about the world, but after all, scientists do experiments, and we wanted to see if children are experiments. When children do experiments we call it “getting everything” or 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 one from Legare’s lab. What Cristine did was use our Blicket Detectors. And she did was show children that yellow ones made it go red ones didn’t, and then she showed them an anomaly. And what you’ll see is that little boy will go through five hypotheses in the of two minutes.
(Video) Boy: How about this? Same as the 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 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 like this, and this 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, to try it out onto the other location. Not working either.
Boy: Oh, because the light goes only 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. So when you put four. So put four on this one to make it light up and two 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, when you them to explain something, what they really do is do a series of experiments. This is actually typical of four year-olds.
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Well, what’s it to be this kind of creature? What’s it like 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 and young children were barely conscious if they were at all. And I think just the opposite is true. think babies and children are actually more conscious than we are as adults. Now here’s what we about how adult consciousness works. And adults’ attention and consciousness kind of like a spotlight. So what happens for adults is decide that something’s relevant or important, we should pay attention to it. consciousness of that thing that we’re attending to becomes extremely bright and vivid, everything else sort of goes dark. And we even know something about the way the does this.
So what happens when we pay attention is that the prefrontal cortex, the sort executive part of our brains, sends a signal that makes little part of our brain much more flexible, more plastic, better learning, and shuts down activity in all the rest our brains. So we have a very focused, purpose-driven kind attention. If we look at babies and young children, see something very different. I think babies and young children seem have 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 sources at once. And if you actually look in brains, you see that they’re flooded with these neurotransmitters that really good at inducing learning and plasticity, and the parts haven’t come on yet. So when we say that and young children are bad at paying attention, what we really mean is that they’re bad at paying attention. So they’re bad at getting rid of all interesting things 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 from those butterflies who are designed to learn.
Well if we to think about a way of getting a taste of kind of baby consciousness as adults, I think the thing is think about cases where we’re put in a situation that we’ve never been in before — when we in love with someone new, or when we’re in new city for the first time. And what happens then is that our consciousness contracts, it expands, so that those three days in Paris seem to be more of consciousness and experience than all the months of being walking, talking, faculty meeting-attending zombie back home. And by the way, coffee, that wonderful coffee you’ve been drinking downstairs, actually mimics the of 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 three double-espressos. (Laughter) That’s fantastic way to be, but it does tend to leave you waking up 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 and the street by ourselves. And it makes sense that we put a lot effort into making babies think like adults do. But if what we want is to like those butterflies, to have open-mindedness, open learning, imagination, creativity, innovation, maybe at least some of the time should be getting the adults to start thinking more children.
(Applause)