What is going on in this baby’s mind? you’d asked people this 30 years ago, most people, including psychologists, would said that this baby was irrational, illogical, egocentric — that he couldn’t take the perspective of another or understand cause and effect. In the last 20 years, developmental science has completely overturned that picture. So in ways, we think that this baby’s thinking is like thinking of the most brilliant scientists.
Let me give you one example of this. One thing that this baby could be about, that could be going on in his mind, trying to figure out what’s going on in the of that other baby. After all, one of the things that’s hardest for of us to do is to figure out what other are thinking and feeling. And maybe the hardest thing of all 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 babies and young children could understand this really profound thing about other people. the question 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, you’ll get is a beautiful stream of consciousness monologue about ponies and birthdays things like that. So how do we actually ask them the question?
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it turns out that the secret was broccoli. What we — Betty Rapacholi, who was one of my students, and — was actually to give the babies two bowls food: one bowl of raw broccoli and one bowl of delicious goldfish crackers. all of the babies, even in Berkley, like the crackers and don’t the raw broccoli. (Laughter) But then what Betty did was take a little taste of food from each bowl. And she would as if she liked it or she didn’t. So half the time, she acted as if liked the crackers and didn’t like the broccoli — just like a baby and other sane person. But half the time, what she would do is take a little bit of broccoli and go, “Mmmmm, broccoli. I tasted the broccoli. Mmmmm.” And then she would take a little bit of crackers, and she’d go, “Eww, yuck, crackers. I tasted the crackers. Eww, yuck.” So she’d act if what she wanted was just the opposite of what babies wanted. We did this with 15 and 18 month-old babies. And then she simply put her hand out and say, “Can you give me some?”
So the is: What would the baby give her, what they liked or what she liked? And the remarkable thing that 18 month-old babies, just barely walking and talking, give her the crackers if she liked the crackers, but they would her the broccoli if she liked the broccoli. On the other hand, 15 month-olds would stare at her a long time if she acted as if she liked the broccoli, like they couldn’t this out. But then after they stared for a long time, 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 this really fact about human nature, that we don’t always want the thing. And what’s more, they felt that they should actually do things to help other people get what wanted.
Even more remarkably though, the fact that 15 month-olds didn’t do this suggests that 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 and 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: Why do children so much? And how is it possible for them learn so much in such a short time? I mean, all, if you look at babies superficially, they seem pretty useless. And actually in many ways, they’re 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 to this puzzle of why we so much time taking care of useless babies, it turns out that there’s an answer. If we look across many, many different species of animals, just us primates, but also including other mammals, birds, even like kangaroos and wombats, it turns out that there’s a relationship between how long a childhood a species and how big their brains are compared to their and how smart and flexible they are.
And sort of the posterbirds for idea are the birds up there. On one side is New Caledonian crow. And crows and other corvidae, ravens, rooks and so forth, are incredibly smart birds. They’re smart as chimpanzees in some respects. And this is a on the cover of science who’s learned how to a tool to get food. On the other hand, we have our friend the domestic chicken. And and ducks and geese and turkeys are basically as as dumps. So they’re very, very good at pecking for grain, and they’re much good at doing anything else. Well it turns out that the babies, the Caledonian crow babies, are fledglings. They depend on their moms 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 mature within a couple of months. So 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 connected to knowledge and learning. Well what kind of explanation could we have for this? Well some animals, the chicken, seem to be beautifully suited to doing one thing very well. So they seem to be beautifully to pecking grain in one environment. Other creatures, like crows, aren’t very good at doing anything in particular, but they’re extremely good learning about laws of different environments.
And of course, we human beings are out on the end of the distribution like the crows. We have brains relative to our bodies by far than any animal. We’re smarter, we’re more flexible, we can learn more, we survive more different environments, we migrated to cover the world even go to outer space. And our babies and children are on us for much longer than the babies of any other species. My son 23. (Laughter) And at least until they’re 23, we’re still popping those worms into little open mouths.
All right, why would we see correlation? Well an idea is that that strategy, that learning strategy, an extremely powerful, great strategy for getting on in the world, it has one big disadvantage. And that one big is that, until you actually do all that learning, you’re going to be helpless. So don’t want to have the mastodon charging at you and be saying to yourself, “A or maybe a spear might work. Which would actually be better?” You want to know that before the mastodons actually show up. And the way the seems to have solved that problem is with a kind division of labor. So the idea is that we have this early period when we’re protected. We don’t have to do anything. All we to do is learn. And then as adults, we can take all those things we learned when we were babies and children and put them to work to do things out there the world.
So one way of thinking about it is that babies and young children are the research and development division of the human species. they’re the protected blue sky guys who just have 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 children and actually put them to use. Another of thinking about it is instead of thinking of babies and children as being like defective grownups, we think about them as being a different developmental stage of the same species — of like caterpillars and butterflies — except that they’re actually brilliant butterflies who are flitting around the garden and exploring, and we’re the caterpillars are inching along our narrow, grownup, adult path.
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If this true, if these babies are designed to learn — and evolutionary story would say children are for learning, that’s what they’re for — might expect that they would have really powerful learning mechanisms. And fact, the baby’s brain seems to be the most powerful learning computer on the planet. But real are actually getting to be a lot better. And there’s been revolution in our understanding of machine learning recently. And it all on the ideas of this guy, the Reverend Thomas Bayes, was a statistician and mathematician in the 18th century. And essentially Bayes did was to provide a mathematical way using probability theory characterize, describe, the way that scientists find out about the world. what scientists do is they have a hypothesis that they think might be likely to with. They go out and test it against the evidence. The evidence makes them change that hypothesis. Then they that new hypothesis and so on and so forth. what Bayes showed was a mathematical way that you could that. And that mathematics is at the core of the best machine programs that we have now. And some 10 years ago, suggested that babies might be doing the same thing.
So if you want to know what’s 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 making calculations with conditional probabilities that they’re revising to figure out the world works. All right, now that might seem like an even order to actually demonstrate. Because after all, if you ask grownups about statistics, they look extremely stupid. How could be that children are doing statistics?
So to test we used a machine that we have called the Blicket Detector. This is box that lights up and plays music when you put some things on it and others. And using this very simple machine, my lab and others have done of studies showing just how good babies are at learning about world. Let me mention just one that we did with Tumar Kushner, my student. If I showed you detector, you would be likely to think to begin with that the to make the detector go would be 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 wouldn’t ever think of to begin with, the detector actually activate two out of three times. Whereas, if do the likely thing, put the block on the detector, it will only activate two out of times. So the unlikely hypothesis actually has stronger evidence. It looks as the waving is a more effective strategy than the other strategy. So we did this; we gave four year-olds this pattern of evidence, and we just them to make it go. And sure enough, the year-olds used the evidence to wave the object on top the detector.
Now there are two things that are really interesting about this. first one is, again, remember, these are four year-olds. They’re learning how to count. But unconsciously, they’re doing these complicated calculations that will give them a conditional probability measure. And the other interesting thing is they’re using that evidence to get to an idea, to a hypothesis about the world, that seems very unlikely to begin with. in studies we’ve just been doing in my lab, similar studies, we’ve show four year-olds are actually better at finding out an unlikely hypothesis than adults are when we give them the same task. So in these circumstances, the children are statistics to find out about the world, but after all, scientists do experiments, and we wanted to see if children are doing experiments. children do experiments we call it “getting into everything” else “playing.”
And there’s been a bunch of interesting studies recently that have shown playing around is really a kind of experimental research program. Here’s one from Cristine Legare’s lab. What Cristine was use our Blicket Detectors. And what 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 this boy will go through five hypotheses in the space of two minutes.
(Video) Boy: How this? Same 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 scientist will 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 the experimenter to do this, to try putting it onto the other location. Not working either.
Boy: Oh, because the light goes to here, not here. Oh, the bottom of this has electricity in here, but this doesn’t have electricity.
AG: Okay, that’s fourth hypothesis.
Boy: It’s lighting up. So when you four. So you put four on this one to make it up and 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 articulate boy, but what Cristine discovered is this is actually quite typical. If look at the way children play, when you ask them to something, what they really do is do a series of experiments. This is actually pretty typical four year-olds.
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Well, what’s it like to this kind of creature? What’s it like to be one of brilliant butterflies who can test five hypotheses in two minutes? Well, if you go back to those and philosophers, a lot of them have said that babies and young children were barely if they were conscious at all. And I think just the is true. I think babies and children are actually more conscious than we as adults. Now here’s what we know about how adult consciousness works. And adults’ attention consciousness look kind of like a spotlight. So what happens for is we decide that something’s relevant or important, we should pay to it. Our consciousness of that thing that we’re attending to becomes extremely bright and vivid, everything else sort of goes dark. And we even know about the way the brain does this.
So what happens we pay attention is that the prefrontal cortex, the sort executive part of our brains, sends a signal 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 a very focused, purpose-driven kind of attention. If we look at and young children, we see something very different. I think and young children seem to have more of a lantern of consciousness than a spotlight of consciousness. So and young children are very bad at narrowing down just one thing. But they’re very good at taking in of information from lots of different sources at once. And if you actually look in their brains, see that they’re flooded with these neurotransmitters that are really at inducing learning and plasticity, and the inhibitory parts haven’t come on yet. So when we say that babies young children are bad at paying attention, what we really mean is that they’re bad at not attention. So they’re bad at getting rid of all the 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 expect from those butterflies who designed to learn.
Well if we want to think about a of getting a taste of that kind of baby as adults, I think the best thing is think about cases we’re put in a new situation that we’ve never in before — when we fall in love with someone new, or we’re in a new city for the first time. And what then is not that our consciousness contracts, it expands, that those three days in Paris seem to be more full consciousness and experience than all the months of being a walking, talking, faculty meeting-attending zombie back home. by the way, that coffee, that wonderful coffee you’ve been drinking downstairs, actually the effect of those baby neurotransmitters. So what’s it like be a baby? It’s like being in love in Paris for the time after you’ve had three double-espressos. (Laughter) That’s a fantastic way 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 how wonderful babies are. It’s to be a grownup. We can do things like tie our and cross the street by ourselves. And it makes sense that we put lot of effort into making babies think like adults do. But if what we want is be like those butterflies, to have open-mindedness, open learning, imagination, creativity, innovation, maybe least some of the time we should be getting the adults to start more like children.
(Applause)