What is going on 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 perspective of another person or understand cause and effect. In the last 20 years, developmental science completely overturned that picture. So in some ways, we think that this baby’s thinking like the thinking of the most brilliant scientists.
Let me give you just one example of this. One that this baby could be thinking about, that could be going on in his mind, is trying to out what’s going on in the mind of that 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 all is to figure out that what other people think and feel isn’t exactly like what we think and feel. Anyone who’s followed can testify to how hard that is for some people get. We wanted to know if babies and young could understand this really profound thing about other people. the question is: How could we ask them? Babies, all, can’t talk, and if you ask a three year-old to tell you what thinks, what you’ll get is a beautiful stream of consciousness monologue about and birthdays and things like that. So how do actually ask them the question?
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Well it out that the secret was broccoli. What we did — Rapacholi, who was one of my students, and I — was actually give the babies two bowls of food: one bowl of 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 did was to take a taste of food from each bowl. And she would act as if liked it or she didn’t. So half the time, acted as if she liked the crackers and didn’t 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 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 was the opposite of what the babies wanted. We did this with 15 and 18 month-old babies. And she would simply put her hand out and say, “Can you give me some?”
So the question is: would the baby give her, what they liked or what she liked? And the remarkable was that 18 month-old babies, just barely walking and talking, give her the crackers if she liked the crackers, they would give 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 if she liked the broccoli, like they couldn’t figure this out. But then after they stared a long time, they would just give her the crackers, what they thought everybody must like. there are two really remarkable things about this. The first one is that these 18 month-old babies have already discovered this really profound fact about human nature, that we don’t want the same thing. And what’s more, they felt that should actually do things to help other people get what they wanted.
Even more remarkably though, 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 from when they 15 months old. So children both know more and learn than we ever would have thought. And this is just one of hundreds and 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 learn much? And how is it possible for them to learn so much in a 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 just keeping them alive. But if we turn to for an answer to this puzzle of why we so much time taking care of useless babies, it turns that there’s actually an answer. If we look across many, many species 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 between how long a a species has and how big their brains are compared to their bodies how smart and flexible they are.
And sort of the posterbirds this idea are the birds up there. On one side is 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 is bird on the cover of science who’s learned how to use a tool to food. On the other hand, we have our friend 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 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 really long time the life of a bird. Whereas the chickens are actually within a couple of months. So childhood is the reason why the crows up on the cover of Science and the chickens end up the soup pot.
There’s something about that long childhood that seems to be to knowledge and learning. Well what kind of explanation could we have this? Well some animals, like the chicken, seem to be beautifully suited to doing just thing very well. So they seem to be beautifully suited pecking 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 different environments.
And of course, we human beings are way out on the end of distribution like the crows. We have bigger brains relative to our bodies by far 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 us for much than the babies of any other species. My son 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 an idea that that strategy, that learning strategy, is an extremely powerful, strategy for getting on in the world, but it one big disadvantage. And that one big disadvantage is that, until actually do all that learning, you’re going to be helpless. you don’t want to have the mastodon charging at you and be to yourself, “A slingshot or maybe a spear might work. would actually be better?” You want to know all that before mastodons actually show up. And the way the evolutions seems to have that problem is with a kind of division of labor. So the idea is we have this early period when we’re completely protected. We don’t have to do anything. All we to do is learn. And then as adults, we take all those things that we learned when we were babies and children and actually put to work to do things out there in the world.
So one way of thinking about it is babies and young children are like the research and development division of the species. So they’re the protected blue sky guys who have to 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 them to use. Another way of thinking about it is instead of thinking babies and children as being like defective grownups, we think about them as being a different developmental stage of same species — kind of like caterpillars and butterflies — that they’re actually the brilliant butterflies who are flitting around the and exploring, and we’re the caterpillars who are inching along our narrow, grownup, path.
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If this is true, if these are designed to learn — and this evolutionary story would children are for learning, that’s what they’re for — we might expect that they would really powerful learning mechanisms. And in fact, the baby’s brain seems be the most powerful learning computer on the planet. But real computers are getting to be a lot better. And there’s been a revolution in understanding of machine learning recently. And it all depends the ideas of this guy, the Reverend Thomas Bayes, was a statistician and mathematician in the 18th century. And essentially what Bayes did was provide a mathematical way using probability theory to characterize, describe, the way that scientists find out about world. So what scientists do is they have a that they think might be likely to start with. They go and test it against the evidence. The evidence makes them change hypothesis. Then they test that new hypothesis and so on and so forth. And what Bayes showed a mathematical way that you could do that. And that mathematics is the core of the best machine learning programs that we have now. some 10 years ago, I suggested that babies might be doing the same thing.
So if want to know what’s going on underneath those beautiful eyes, I 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 figure out how world works. All right, now that might seem like an even taller order to actually demonstrate. after 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 we have the Blicket Detector. This is a box that lights up and plays music when you put some on it and not others. And using this very machine, my lab and others have done dozens of studies showing just good babies are at learning about the world. Let me 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 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 strange way. Because if you wave 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 you the likely thing, put the block on the detector, it only activate two out of six times. So the unlikely actually has stronger evidence. It looks as if the 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 enough, the four year-olds used the evidence to wave the object top of the detector.
Now there are two things that are really interesting about this. The first is, again, remember, these are four year-olds. They’re just learning how 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 that evidence to get to an idea, get to a hypothesis about the world, that seems very to begin with. And in studies we’ve just been doing in my lab, similar studies, we’ve show that year-olds are actually better at finding out an unlikely hypothesis than adults are 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 also experiments, and we wanted to see if children are experiments. When children do experiments we call it “getting into everything” or “playing.”
And there’s been a bunch of interesting 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 was use our Detectors. And what she did was show children that yellow ones made go and red ones didn’t, and then she showed an anomaly. And what you’ll see is that this little boy will go through five hypotheses in the of two minutes.
(Video) Boy: How about this? Same the other side.
Alison Gopnik: Okay, so his first has just been falsified.
(Laughter)
Boy: This one lighted up, and this nothing.
AG: Okay, he’s got 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 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 out onto the other location. Not either.
Boy: Oh, because the light goes only to here, not here. Oh, the bottom of this has electricity in here, but this doesn’t have electricity.
AG: Okay, that’s a fourth hypothesis.
Boy: It’s lighting up. So you put four. So you put four on this one make it light up and two on this one to make it up.
AG: Okay,there’s his fifth hypothesis.
Now that is a particularly — is a particularly adorable and articulate little boy, but Cristine discovered is this is actually quite typical. If look at the way children play, when you ask them to explain something, what they really do do a series of experiments. This is actually pretty typical four year-olds.
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Well, what’s it like to be this kind of creature? What’s it like to one of 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 I think just the opposite is true. I babies and children are actually more conscious than we are adults. Now here’s what we know about how adult works. And adults’ attention and consciousness look kind of a spotlight. So what happens for adults 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 bright and vivid, and everything else sort of goes dark. And we even know about the way the brain does this.
So what happens when we pay attention that the prefrontal cortex, the sort of executive part our brains, sends a signal that makes a little part of our brain more flexible, more plastic, better at learning, and shuts down activity in the rest of our brains. So we have a very focused, purpose-driven kind of attention. we look at babies and young children, we see something very different. I think babies and young children to have more of a lantern of consciousness than a spotlight of consciousness. babies and young children are very bad at narrowing down just one thing. But they’re very good at taking lots 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 good at learning and plasticity, and the inhibitory parts haven’t come yet. So when we say that babies and young are bad at paying attention, what we really mean that they’re bad at not paying attention. So they’re at getting rid of all the interesting things that could tell them and just looking at the thing that’s important. That’s kind of attention, the kind of consciousness, that we 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 the best thing is think cases where we’re put in a new situation that we’ve never in before — when we fall in love with someone new, or when we’re a new city for the first time. And what happens then not 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 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 effect of those baby neurotransmitters. So what’s it like to a baby? It’s like being in love in Paris for the first time after you’ve three double-espressos. (Laughter) That’s a fantastic way to be, it does tend to leave you waking up crying at three o’clock in the morning.
(Laughter)
Now it’s to be a grownup. I don’t want to say too much how wonderful babies are. It’s good to be a grownup. We can do things like our shoelaces and cross the street by ourselves. And it makes sense that we put a lot of into making babies think like adults do. But if what we want is to be like butterflies, to have open-mindedness, open learning, imagination, creativity, innovation, maybe at least of the time we should be getting the adults to start more like children.
(Applause)