What is going in this baby’s mind? If you’d asked people this 30 ago, most people, including psychologists, would have said that baby was irrational, illogical, egocentric — that he couldn’t take the perspective of person or understand cause and effect. In the last 20 years, developmental science has completely overturned picture. So in some ways, we think that this baby’s thinking like the thinking of the most brilliant scientists.
Let give you just one example of this. One thing that this baby could be thinking about, that be going on in his mind, is trying to figure out what’s on in the mind of that other baby. After all, of the things that’s hardest for all of us to do is to figure out what people are thinking and feeling. And maybe the hardest thing of all is to out that what other people think and feel isn’t actually exactly like 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 thing about other people. Now the question is: How could 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 a beautiful stream of consciousness monologue about ponies and and things like that. So how do we actually them the question?
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Well it turns out that secret was broccoli. What we did — Betty Rapacholi, who was one my students, and I — was actually to give the two bowls of food: one bowl of raw broccoli and one bowl of delicious goldfish crackers. Now of the babies, even in Berkley, like the crackers and don’t like the broccoli. (Laughter) But then what Betty did was to take little taste of food from each bowl. And she would act as she 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 the time, what she would do is take a little bit the 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 what the babies wanted. We did this with 15 18 month-old babies. And then she would simply put her hand out and say, “Can you me some?”
So the question 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 walking and talking, would her the crackers if she liked the crackers, but they would her the broccoli if she liked the broccoli. On the hand, 15 month-olds would stare at her for a long time if she acted as if liked the broccoli, like they couldn’t figure this out. But after they stared for a long time, they would give her the crackers, what they thought everybody must like. So there two really remarkable things about this. The first one is these little 18 month-old babies have already discovered this really profound about human nature, that we don’t always want the same thing. what’s more, they felt that they should actually do things help other people get what they wanted.
Even more though, the fact that 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 more and learn more than we ever would have thought. And this just one of hundreds and hundreds of studies over the last 20 that’s actually demonstrated it.
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The question you might though is: Why do children learn so much? And how is possible for them to learn so much in such a short time? I mean, after all, if look at babies superficially, they seem pretty useless. And actually in many ways, they’re worse than useless, because have to put so much time and energy into just keeping them alive. But we turn to evolution for an answer to this puzzle of we spend so much time taking care of useless babies, it out that there’s actually an answer. If we look across many, many species of animals, not just us primates, but also including mammals, birds, even marsupials like kangaroos and wombats, it turns that there’s a relationship between how long a childhood species has and how big their brains are compared to their bodies and how smart and they are.
And sort of the posterbirds for this idea are birds up there. On one side is a New Caledonian crow. crows and other corvidae, ravens, rooks and so forth, are incredibly smart birds. They’re as as chimpanzees in some respects. And this is a on the 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 geese and turkeys basically as dumb 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 babies, the New Caledonian crow babies, are fledglings. They depend on moms to 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 are actually mature within a couple of months. So is the reason why the crows end up on the cover of Science and chickens end up in the soup pot.
There’s something about that long childhood that seems to be to knowledge and learning. Well what kind of explanation could have for this? Well some animals, like the chicken, seem to be beautifully suited to 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 good at doing anything particular, but they’re extremely good at learning about laws of environments.
And of course, we human beings are way on the end of the distribution like the crows. We have bigger relative to our bodies by far than any other animal. We’re smarter, we’re more flexible, we can learn more, survive in more different environments, we migrated to cover the world and even go to space. And our babies and children are dependent on for much longer than the babies of any other species. son is 23. (Laughter) And at least until they’re 23, we’re still those worms into those little open mouths.
All right, why would we see this correlation? Well idea is that that strategy, that learning strategy, is an extremely powerful, great strategy for getting on in world, but it has one big disadvantage. And that one big disadvantage is that, until you do all that learning, you’re going to be helpless. So you don’t to have the mastodon charging at you and be to yourself, “A slingshot or maybe a spear might work. Which would actually better?” You want to know all that before the actually show up. And 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. don’t have to do anything. All we have to do is learn. then as adults, we can take all those things that we learned when we were babies and children actually put them to work to do things out there the world.
So one way of thinking about it is that babies young children are like the research and development division of the human species. So they’re the blue sky guys who just have to go out and learn and have good ideas, and we’re and marketing. We have to take all those ideas that learned when we were children and actually put them to use. Another way thinking about it is instead of thinking of babies children as being like defective grownups, we should think about them being a different developmental stage of the same species — kind of caterpillars and butterflies — except that they’re actually the butterflies who are flitting around the garden and exploring, we’re the caterpillars who are inching along our narrow, grownup, 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 in fact, the baby’s brain to be the most powerful learning computer on the planet. But real computers are actually to be a lot better. And there’s been a revolution in our understanding of machine recently. And it all depends on the ideas of this guy, the Thomas Bayes, who was a statistician and mathematician in 18th century. And essentially what Bayes did was to provide a mathematical way using probability to characterize, describe, the way that scientists find out about the world. So what scientists do is they a hypothesis that they think might be likely to start with. They go out and test against the evidence. The evidence makes them change that hypothesis. Then they test that new hypothesis so on and so forth. And what Bayes showed was a mathematical way you could do that. And that mathematics is at core of the best machine learning programs that we have now. some 10 years ago, I suggested that babies might be the same thing.
So if you want to know what’s going on underneath those brown eyes, I think it actually looks something like this. This is Reverend Bayes’s notebook. So I those babies are actually making complicated calculations with conditional probabilities they’re revising to figure out how the world works. All right, now that might seem like even taller 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 this we used a machine we have called the Blicket Detector. This is a box that up and plays music when you put some things on and not others. And using this very simple machine, my lab others have done dozens of studies showing just how good babies are learning 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 to to begin with that the way to make the detector go would be to a block on top of the detector. But actually, this detector works in a bit a strange way. Because if you wave a block the top of the detector, something you wouldn’t ever think to begin with, the detector will actually activate two out of three times. Whereas, if you the likely thing, put the block on the detector, it will only activate two out six times. So the unlikely 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 four year-olds pattern of evidence, and we just asked them to it go. And sure enough, the four year-olds used the evidence to the object on top of the detector.
Now there two things that are really interesting about this. The first is, again, remember, these are four year-olds. They’re just learning how to count. But unconsciously, they’re these quite complicated calculations that will give them a probability measure. And the other interesting thing is that they’re using that to get to an idea, get to a hypothesis about world, that seems very unlikely to begin with. And in we’ve just been doing in my lab, similar studies, we’ve that four year-olds are actually better at finding out an hypothesis than adults are when we give them exactly same task. So in these circumstances, the children 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 been a bunch interesting studies recently that have shown this playing around really a kind of experimental research program. Here’s one from Cristine Legare’s lab. What Cristine did was use Blicket Detectors. And what she did was show children that yellow ones made it go and red didn’t, and then she showed them an anomaly. And you’ll see is that this little boy will go five hypotheses in the space of two minutes.
(Video) Boy: How about this? Same the other side.
Alison Gopnik: Okay, so his first hypothesis just been falsified.
(Laughter)
Boy: This one lighted up, this one nothing.
AG: Okay, he’s got his experimental notebook out.
Boy: What’s this light up. (Laughter) I don’t know.
AG: Every will recognize that expression of despair.
(Laughter)
Boy: Oh, it’s because this to be like this, and this needs to be 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 out 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, but this doesn’t electricity.
AG: Okay, that’s a fourth hypothesis.
Boy: It’s up. So when you put four. So you put four on one to make it light up and two on 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 you at the way children play, when you ask them to explain something, what they really do is do series of experiments. This is actually 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 these brilliant butterflies who can test five hypotheses in two minutes? Well, if go back to those psychologists and 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 are actually more conscious than we are as adults. here’s what we know about how adult consciousness works. And adults’ and consciousness look kind of like a spotlight. So what for adults is we decide that something’s relevant or important, we should pay attention to it. Our consciousness 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 brain does this.
So what happens when we pay attention is that the prefrontal cortex, the sort of 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 of attention. If we look at babies and young children, we see something very different. I babies and young children seem to have more of a of consciousness than a spotlight of consciousness. So babies and children are very bad at narrowing down to just thing. But they’re very good at taking in lots of information from lots of different 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 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 rid of all the interesting things that could tell something and just looking at the thing that’s important. That’s the kind of attention, the kind of consciousness, that might expect from those butterflies who are designed to learn.
Well we want to think about a way of getting taste of that kind of baby consciousness as adults, I think best thing is think about cases where we’re put in a new situation that we’ve never been before — when we fall in love with someone new, or when we’re in a city for the first time. And what happens then not that our consciousness contracts, it expands, so that 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 of those baby neurotransmitters. So what’s it like to a 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 you waking crying at three o’clock in the morning.
(Laughter)
Now it’s good to be a grownup. I don’t want say too much about how wonderful babies are. It’s to be a grownup. We can do things like our shoelaces and cross the 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 to start thinking more like children.
(Applause)