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