What is going on in this baby’s mind? you’d asked people this 30 years ago, most people, psychologists, would have said that this baby was irrational, illogical, egocentric — that couldn’t take the perspective of another person or understand cause and effect. the last 20 years, developmental science has completely overturned that picture. So in ways, we think that this baby’s thinking is like the thinking of most brilliant scientists.
Let me give you just one example of this. thing that this baby could be thinking about, that be going on in his mind, is trying to figure out what’s going on the mind of that other baby. After all, one of the things that’s for all of us to do is to figure out what other people thinking and feeling. And maybe the hardest thing of all to figure out that what other people think and feel isn’t actually like what we think and feel. Anyone who’s followed politics can testify to how hard that is some people to get. We wanted 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, and you ask a three year-old to tell you what he thinks, what you’ll get a 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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it 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 of food: one bowl 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 to take 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 if she liked the crackers and didn’t like the broccoli — just like a baby any other sane person. But half the time, what she would do is take a little bit the broccoli and go, “Mmmmm, broccoli. I tasted the broccoli. Mmmmm.” And she would take a little bit of the crackers, and she’d go, “Eww, yuck, crackers. tasted the crackers. Eww, yuck.” So she’d act as if what she wanted just the opposite of what the babies wanted. We did with 15 and 18 month-old babies. And then she simply put her hand out and say, “Can you give me some?”
So the question is: What the baby give her, what they liked or what she liked? And the thing was that 18 month-old babies, just barely walking and talking, would give her crackers if she liked the crackers, but they would give 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 couldn’t figure this out. But then after they stared for a long time, would just give her the crackers, what they thought everybody must like. So there are really remarkable things about this. The first one is that little 18 month-old babies have already discovered this really profound fact human nature, that we don’t always want the same thing. what’s more, they felt that they should actually do things to help other people get they wanted.
Even more remarkably though, the fact that 15 month-olds didn’t do suggests that these 18 month-olds had learned this deep, profound fact about human nature the three months from when they were 15 months old. So children both know more and learn more than ever would have thought. And this is just one of and hundreds of studies over the last 20 years that’s actually demonstrated it.
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The question you might though is: Why do children learn so much? And how is it possible for them to so much in such a short time? I mean, after all, if you look babies superficially, they seem pretty useless. And actually in many ways, they’re worse than useless, because we to put so much time and energy into just keeping them alive. But if we turn evolution for an answer to this puzzle of why we spend so time taking care of useless babies, it turns out there’s actually an answer. If we look across many, many different of animals, not just us primates, but also including other mammals, birds, even marsupials like and wombats, it turns out that there’s a relationship how long a childhood a species has and how big their are compared to their bodies and how smart and flexible are.
And sort of the posterbirds for this idea are the birds up there. one side is a New Caledonian crow. And crows 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 the of science 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 and and turkeys are basically as dumb as dumps. So they’re very, very at pecking for grain, and they’re not much good at doing anything else. Well it turns out the babies, the New Caledonian crow babies, are fledglings. They depend on their moms to drop worms their little open mouths for as long as two years, which a really long time in the life of a bird. Whereas the chickens are actually mature within a couple months. So childhood is the reason why the crows end on the cover of Science and the chickens end in the soup pot.
There’s something about that long that seems to be connected to knowledge and learning. what kind of explanation could we have for this? Well some animals, like the chicken, seem to beautifully suited to doing just one thing very well. they seem to be beautifully suited to pecking grain in one environment. Other creatures, the crows, aren’t very good at doing anything in particular, but they’re extremely good at learning about laws 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 other animal. We’re smarter, we’re more flexible, we can more, we survive in more different environments, we migrated to cover world and even go to outer space. And our and children are dependent on us for much longer than babies of any other species. My son is 23. (Laughter) And least until they’re 23, we’re still popping those worms those little open mouths.
All right, why would we this correlation? Well an idea is that that strategy, that learning strategy, is an extremely powerful, strategy for getting on in the world, but it has big disadvantage. And that one big disadvantage is that, until actually do all that learning, you’re going to be helpless. So you don’t want to have the charging at you and be saying to yourself, “A slingshot or maybe a spear work. Which would actually be better?” You want to know that before the mastodons actually show up. And the the evolutions seems to have solved that problem is with a kind of division of labor. the idea is that we have this early period when we’re completely protected. We don’t have to anything. All we have to do is learn. And as adults, we can take all those things that learned when we were babies and children and actually put them to work to do out there in 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 protected sky guys who just have to go out and learn and good 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 of thinking of and children as being like defective grownups, we should think about them as being a different developmental of the same species — kind of like caterpillars and butterflies — except they’re actually the brilliant butterflies who are flitting around garden and exploring, and we’re the caterpillars who are inching along narrow, grownup, adult path.
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If this is true, if these are designed to learn — and this evolutionary story would say children are for learning, that’s they’re for — we might expect that they would have really powerful mechanisms. And in fact, the baby’s brain seems to be the most learning computer on the planet. But real computers are actually getting to a lot better. And there’s been a revolution in our understanding of machine learning recently. And all depends on the ideas of this guy, the Reverend Thomas Bayes, who was a and mathematician in the 18th century. And essentially what did was to provide a mathematical way using probability theory to characterize, describe, the way that scientists find about the world. So what scientists do is they a hypothesis that they think might be likely to start with. go out and test it against the evidence. The evidence them change that hypothesis. Then they test that new and so on and so 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 years ago, I suggested that might be doing the same thing.
So if you want know what’s going on underneath those beautiful brown eyes, think it actually looks something like this. This is Bayes’s notebook. So I think those babies are actually complicated calculations with conditional probabilities that they’re revising to out how the world works. All right, now that seem like an even taller order to actually demonstrate. Because after all, if ask even grownups about statistics, they look extremely stupid. could it be that children are doing statistics?
So to test this we used machine that we have called the Blicket Detector. This is a that lights up and plays music when you put some on it and not others. And using this very simple machine, my lab and others have dozens of studies showing just how good babies are at learning the world. Let me mention just one that we did with 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 in bit of a strange way. Because if you wave a block over the top of the detector, you wouldn’t ever think of to begin with, the detector will activate two out of three times. Whereas, if you do the 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 waving is a 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 make it go. And sure enough, the year-olds used the evidence to wave the object on top of detector.
Now there are two things that are really about this. The first one is, again, remember, these are year-olds. They’re just learning how to count. But unconsciously, they’re these quite complicated calculations that will give them a conditional probability measure. And other interesting thing is that they’re using that evidence to get an idea, get to a hypothesis about the world, that seems very unlikely to with. And in studies we’ve just been doing in my lab, similar studies, we’ve show that four year-olds actually better at finding out an unlikely hypothesis than are when we give them exactly the same task. So in these circumstances, the children are statistics to find out about the world, but after all, scientists also do experiments, and we wanted to if children are doing experiments. When children do experiments call it “getting into everything” or else “playing.”
And there’s been a bunch of interesting studies recently have shown this playing around is really a kind of experimental research program. Here’s from Cristine Legare’s lab. What Cristine did was use Blicket Detectors. And what she did was show children yellow ones made it go and red ones didn’t, then she showed them an anomaly. And what you’ll is that this little boy will go through five hypotheses in space of two minutes.
(Video) Boy: How about this? as the other 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 his experimental notebook out.
Boy: What’s making this light up. (Laughter) I don’t know.
AG: Every scientist will recognize that of despair.
(Laughter)
Boy: Oh, it’s because this needs to be like this, and this needs to like this.
AG: Okay, hypothesis two.
Boy: That’s why. Oh.
(Laughter)
AG: Now this is next idea. He told the experimenter to do this, to try putting it out onto other location. Not working either.
Boy: Oh, because the light goes only here, not here. Oh, the bottom of this box electricity in here, but this doesn’t have electricity.
AG: Okay, that’s a hypothesis.
Boy: It’s lighting up. So when you put four. So you put four on this to make it light up and two on this one to it light up.
AG: Okay,there’s his fifth hypothesis.
Now that a particularly — that is a particularly adorable and articulate little boy, what Cristine discovered is this is actually quite typical. If you look at the way play, when you ask them to explain something, what 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 these 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 conscious they were conscious at all. And I think just the is true. I think babies and children are actually more than we are as adults. Now here’s what we know about adult consciousness works. And adults’ attention and consciousness look of like a spotlight. So what happens for adults we 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 the way the brain does this.
So what happens we pay attention is that the prefrontal cortex, the sort of executive part of our brains, a signal that makes a little part of our brain much more flexible, more plastic, at learning, and shuts down activity in all the rest of brains. So we have a very focused, purpose-driven kind of attention. we look at babies and young children, we see very different. I think babies and young children seem have more of a lantern of consciousness than a spotlight of consciousness. So babies young children are very bad at narrowing down to just one thing. But they’re very at taking in lots of information from lots of different sources at once. if you actually look in their brains, you see that they’re flooded with these neurotransmitters that are good at inducing learning and plasticity, and the inhibitory parts haven’t come on yet. So we say that babies and young children are bad at paying attention, what we really is that they’re bad at not paying attention. So they’re at getting rid of all the interesting things that could them something and just looking at the thing that’s important. That’s kind of attention, the kind of consciousness, that we might expect 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 best thing is think about cases we’re put in a new situation that we’ve never been in before — when fall 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 seem to be more full of consciousness and experience than all the months of 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 love in Paris for the first time after you’ve had double-espressos. (Laughter) That’s a fantastic 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 grownup. I don’t want to say too much about wonderful babies are. It’s good to be a grownup. can do things like tie our shoelaces and cross street by ourselves. And it makes sense that we put a lot of effort into making babies think adults do. But if what we want is to be like those butterflies, to have open-mindedness, learning, imagination, creativity, innovation, maybe at least some of the time should be getting the adults to start thinking more children.
(Applause)