What is on in this baby’s mind? If you’d asked people this 30 years ago, most people, including psychologists, would said that this baby was irrational, illogical, egocentric — he couldn’t take the perspective of another person or understand cause and effect. In the last 20 years, science has completely overturned that picture. So in some ways, we think that this baby’s is like the thinking of the most brilliant scientists.
Let me give you one example of this. One thing that this baby could be thinking about, that be going on in his mind, is trying to figure what’s going on in the mind of that other baby. After all, one of the that’s hardest for all of us to do is to figure out other 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 how hard that is for some people to get. We to know if babies and young children could understand this really profound about other people. Now the question is: How could we ask them? Babies, after all, can’t talk, if you ask a three year-old to tell you he thinks, what you’ll get is a beautiful stream of monologue about ponies and birthdays and things like that. how do we actually ask them the question?
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Well it turns out that the secret was broccoli. we did — Betty Rapacholi, who was one of my students, I — was actually to give the babies two bowls food: one bowl of raw broccoli and one bowl delicious goldfish crackers. Now all of the babies, even Berkley, like the crackers and don’t like the raw broccoli. (Laughter) But then what did was to take a little taste of food from bowl. And she would act as if she liked it 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 any other sane person. 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 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 wanted. We 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 question is: What would the baby give her, what they liked 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 would stare at her for a long if she acted as if she liked the broccoli, like they couldn’t figure this out. But then after stared for a long time, they would just give the crackers, what they thought everybody must like. So are two really remarkable things about this. The first is that these little 18 month-old babies have already discovered really profound fact about human nature, that we don’t always want same thing. And what’s more, they felt that they should do things to help other people get what they wanted.
Even remarkably though, the fact that 15 month-olds didn’t do this suggests that 18 month-olds had learned this deep, profound fact about nature in the three months from when they were 15 old. So children both know more and learn more than we ever would have thought. And this is one of hundreds and hundreds of studies over the last 20 that’s actually demonstrated 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 such a short time? I mean, after all, if you look at babies superficially, they pretty useless. And actually in many ways, they’re worse than useless, because we have to put so time and energy into just keeping them alive. But if we to evolution for an answer to this puzzle of why spend so much time taking care of useless babies, it turns out there’s actually an answer. If we look across 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 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 the 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, incredibly smart birds. They’re as smart as chimpanzees in some respects. And this a bird on the cover of science who’s learned how to a tool to get food. On the other hand, we our friend 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, and they’re not much good at doing else. Well it turns out that the babies, the New Caledonian crow babies, are fledglings. depend on their moms to drop worms in their little open mouths as long as two years, which is a really long in the life of a bird. Whereas the chickens are actually mature a couple of months. So childhood is the reason why the crows end up on the cover Science and the chickens end up in the soup pot.
There’s something about long childhood that seems to be connected to knowledge and learning. Well what of explanation could we have for this? Well some animals, like the chicken, seem to be beautifully suited to just one thing very well. So they seem to beautifully suited to pecking grain in one environment. Other creatures, like the crows, aren’t good at doing anything in particular, but they’re extremely good learning about laws of different environments.
And of course, we human beings are way out on 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 in more different environments, we to cover the world and even go to outer space. our babies and children are dependent on us for much 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 those open mouths.
All right, why would we see this correlation? Well an idea is that that strategy, learning strategy, is an extremely powerful, great strategy for getting on in the world, but has one big disadvantage. And that one big disadvantage that, until you actually do all that learning, you’re going be helpless. So you don’t want to have the charging at you and be saying to yourself, “A or maybe a spear might work. Which would actually be better?” You want to all that before the 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 when we’re completely protected. We don’t have do anything. All we have to do is learn. And then as adults, we take all those things that we learned when we babies and children and actually put them to work to do 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 sky guys who just have to go out and and have good ideas, and we’re production and marketing. We have to take all those ideas that 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, should think about them as being a different developmental stage of the same species — of like caterpillars and butterflies — except that they’re the brilliant butterflies who are flitting around the garden exploring, and we’re the caterpillars who are inching along narrow, grownup, adult path.
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If this is true, if these babies are designed to learn — this evolutionary story would say children are for learning, that’s what they’re for — might expect that they would have really powerful learning mechanisms. in fact, the baby’s brain seems to be the powerful learning computer on the planet. But real computers are 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. essentially what Bayes did was to provide a mathematical using probability theory to characterize, describe, the way that scientists out about the world. So what scientists do is they have hypothesis that they think might be likely to start with. go out and test it 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 that you do that. And that mathematics is at the core of the best machine learning programs we have now. And some 10 years ago, I suggested that babies 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 making complicated calculations with conditional probabilities that they’re revising to figure out how the works. All right, now that might seem 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 have called the Blicket Detector. This is a box that lights up and 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 about the world. Let me mention just one that did with Tumar Kushner, my student. If I showed you this detector, you would be likely think to begin with that the way to make the detector go be to put a block on top of the detector. But actually, this detector works a bit of a strange way. Because if you wave a block the top of the detector, something you wouldn’t ever of to begin with, the detector will actually activate two out three times. Whereas, if you do the likely thing, put the block on the detector, it only activate two out of six times. So the hypothesis actually has stronger evidence. It looks as if the waving is more effective strategy than the other strategy. So we did just this; we gave year-olds this pattern of evidence, and we just asked them make it go. And sure enough, the four year-olds used evidence to wave the object on top of the detector.
Now there are two that are really interesting about this. The first one is, again, remember, are four year-olds. They’re just learning how to count. But unconsciously, they’re doing these quite calculations that will give them a conditional probability measure. And the other interesting thing is that they’re using evidence to get to an idea, get to a hypothesis about the world, that very unlikely to begin with. And in studies we’ve just been doing in my lab, similar studies, we’ve that four year-olds are actually better at finding out an unlikely than adults are when we give them exactly the task. So in these circumstances, the children are using statistics to find out the world, but after all, scientists also do experiments, and wanted to see if children are doing experiments. When children do experiments we call “getting into everything” or else “playing.”
And there’s been a bunch of studies recently that have shown this playing around is a kind of experimental research program. Here’s one from Cristine Legare’s lab. What Cristine did use our Blicket Detectors. And what she did was show that yellow ones made it go and red ones didn’t, and then she showed them an anomaly. And you’ll see is that this little boy will go through hypotheses in the space of two minutes.
(Video) Boy: How about this? Same as the side.
Alison Gopnik: Okay, so his first hypothesis has just been falsified.
(Laughter)
Boy: one lighted up, and this one nothing.
AG: Okay, he’s his experimental notebook out.
Boy: What’s making this light up. (Laughter) don’t know.
AG: Every scientist will recognize that expression 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 putting it out onto other location. Not working either.
Boy: Oh, because the goes only to here, not here. Oh, the bottom of this box has in here, but this doesn’t have electricity.
AG: Okay, that’s a fourth hypothesis.
Boy: It’s up. So when you put four. So you put four on this one to make light up and two on this one to make light up.
AG: Okay,there’s his fifth hypothesis.
Now that is a particularly — that a particularly adorable and articulate little boy, but what Cristine discovered this is actually quite 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. is actually pretty 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 butterflies who can test five hypotheses in two minutes? Well, you go back to those psychologists and philosophers, a lot of them have said that babies young children were barely conscious if they were conscious at all. And I think just the opposite true. I think babies and children are actually more than we are as adults. Now here’s what we know about how adult consciousness works. And adults’ and consciousness look kind of like a spotlight. So what happens for is we decide that something’s relevant or important, we should pay attention to it. Our of that thing that we’re attending to becomes extremely bright and vivid, and else sort of goes dark. And we even know something about the way the brain does this.
So happens when we pay attention is that the prefrontal cortex, the sort of executive of our brains, sends a signal that makes a little of our brain much more flexible, more plastic, better at learning, shuts down activity in all the rest of our brains. So we a very focused, purpose-driven kind of attention. If we at babies and young children, we see something very different. I babies and young children seem to have more of lantern of consciousness than a spotlight of consciousness. So and young children are very bad at narrowing down to just one thing. But they’re very good taking in lots of information from lots of different sources once. And if you actually look in their brains, you see that they’re flooded with these neurotransmitters that really good at inducing learning and plasticity, and the inhibitory parts haven’t on yet. So when we say that babies and children are bad at paying attention, what we really is that they’re bad at not paying 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 kind of attention, the kind of consciousness, that we might expect from butterflies who are designed to learn.
Well if we want to think about a way of getting a of that kind of baby consciousness as adults, I think the best thing is think cases where we’re put in a new situation that we’ve been in before — when we fall in love with new, or when we’re in a new city for the first time. And what happens is not that our consciousness contracts, it expands, so that those days in Paris seem to be more full of consciousness and experience than 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 mimics the of those baby neurotransmitters. So what’s it like to be baby? It’s like being in love in Paris for the time after you’ve had three double-espressos. (Laughter) That’s a way to be, but it does tend to leave waking up crying at three o’clock in the morning.
(Laughter)
Now it’s good to be a grownup. I don’t want to too much about how wonderful babies are. It’s good to be a grownup. can do things like tie our shoelaces and cross the street by ourselves. And it sense that we put a lot of effort into making babies like adults do. But if what we want is to be those butterflies, to have open-mindedness, open learning, imagination, creativity, innovation, at least some of the time we should be getting the adults start thinking more like children.
(Applause)