What going on in this baby’s mind? If you’d asked people this 30 years ago, people, including psychologists, would have said that this baby was irrational, illogical, — that he couldn’t take the perspective of another person 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 is like the thinking of the most brilliant scientists.
Let give you just one example of this. One thing that this baby be thinking about, that could be going on in mind, is trying to figure out what’s going on in mind of that other baby. After all, one of 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 figure out that what other people think and feel isn’t exactly like what we think and feel. Anyone who’s followed politics can testify to how that is for some people to get. We wanted to know 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 is beautiful stream of consciousness monologue about ponies and birthdays and things like that. So how we actually ask them the question?
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Well it turns out the secret was broccoli. What we did — Betty Rapacholi, was one of my students, and I — was actually to give babies two bowls of food: one bowl of raw broccoli and one bowl of delicious crackers. Now all of the babies, even in Berkley, the crackers and don’t like the raw broccoli. (Laughter) But then what Betty did was take a little taste of food from each bowl. And would act as if she liked it or she didn’t. half the time, she acted as if she liked crackers and didn’t like the broccoli — just like baby and any other sane person. But half the time, 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 crackers. Eww, yuck.” So she’d act 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 out and say, “Can you give me some?”
So the is: What would the baby give her, what they liked or what she liked? And the remarkable thing 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. 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 really remarkable things about this. first one is that these little 18 month-old babies have discovered this really profound fact about human nature, that we don’t want the same thing. And what’s more, they felt that they should actually do things to other people get what 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 in three months from when they were 15 months old. children both know more and learn more than we would have thought. And this is just one of hundreds and hundreds of 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 possible for them to learn so much in such a short time? mean, after all, if you look at babies superficially, seem pretty useless. And actually in many ways, they’re worse than useless, we have to put so much time and energy into keeping them alive. But if we turn to evolution an answer to this puzzle of why we spend so much time taking care useless babies, it turns out that there’s actually an answer. we look across many, many different species of animals, not us primates, but also including other mammals, birds, even marsupials like kangaroos and wombats, turns out that there’s a relationship between how long a childhood species has and how big their brains are compared to their bodies and smart and flexible they are.
And sort of the posterbirds for this idea are the 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 smart as in some respects. And this is a bird on cover of science who’s learned how to use a to get food. On the other hand, we have our the domestic chicken. And chickens and ducks and geese and turkeys basically as dumb as dumps. So they’re very, very good pecking for grain, and they’re not much good at doing anything else. Well it out that the babies, the New Caledonian crow babies, are fledglings. They on their moms to drop worms in their little open mouths for as long two years, which is a really long time in the life a bird. Whereas the chickens are actually mature within a couple of months. So childhood is the why the crows end up on the cover of and the chickens end up in the soup pot.
There’s something about that long childhood seems to be connected to knowledge and learning. Well kind of explanation could we have for this? Well animals, like the chicken, seem to be beautifully suited doing just one thing very well. So they seem be beautifully suited to pecking grain in one environment. Other creatures, like the crows, aren’t very 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 bigger brains relative to our bodies by than any other animal. We’re smarter, we’re more flexible, can learn more, we survive in more different environments, we migrated to cover the and even go to outer space. And our babies and children are dependent on us much longer than the babies of any other species. son is 23. (Laughter) And at least until they’re 23, we’re still popping those worms into those little mouths.
All right, why would we see this correlation? Well idea is that that strategy, that learning strategy, is an powerful, great strategy for getting on in the world, but has one big disadvantage. And that one big disadvantage is that, until you actually do that learning, you’re going to be helpless. So you don’t to have the mastodon charging at you and be saying to yourself, “A slingshot or maybe a spear work. Which would actually be better?” You want to know all before the mastodons actually show up. And the way the evolutions 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. don’t have to do anything. All we have to do is learn. And then adults, we can take all those things that we learned when we were babies and children and actually them to work to do things out there in the world.
So way of thinking about it is that babies and young children are like the 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, we’re production and marketing. We have to take all those ideas that we learned when we children and actually put them to use. Another way of thinking about it is instead of thinking babies and children as being like defective grownups, we should 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 the garden and exploring, and we’re the caterpillars who inching along our narrow, grownup, adult path.
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If this true, if these babies 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 have really powerful mechanisms. And in fact, the baby’s brain seems to be most powerful learning computer on the planet. But real computers are actually to be a lot better. And there’s been a revolution in understanding of machine learning recently. And it all depends on ideas of this guy, the Reverend Thomas Bayes, who was a statistician mathematician in the 18th century. And essentially what Bayes did to provide a mathematical way using probability theory to characterize, describe, the way scientists find out about the world. So what scientists do is they have a hypothesis 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 that new hypothesis and so on and so forth. And what Bayes was a mathematical way that you could do that. that mathematics is at the core of the best machine programs that we have now. And some 10 years ago, I suggested that babies might be doing same thing.
So if you want to know what’s going on underneath those beautiful brown eyes, I it actually looks 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 after all, you ask even grownups about statistics, they look extremely stupid. could it be that children are doing statistics?
So to this we used a machine that we have called the Blicket Detector. This a box that lights up and plays music when put some things on it and not others. And this very simple machine, my lab and others have done dozens of showing just how good babies are at learning about world. Let me mention just one that we did with Tumar Kushner, my student. If showed you this detector, you would be likely to think to begin with that the to make the detector go would be to put a block on top of the detector. actually, this detector works in a bit of a strange way. Because if wave a block over the top of the detector, something you wouldn’t ever think of to begin with, detector will actually activate two out of three times. Whereas, if you do likely thing, put the block on the detector, it will activate two out of six times. So the unlikely hypothesis actually has stronger evidence. It as if the waving is a more effective strategy than the other strategy. So did just this; we gave four year-olds this pattern of evidence, we just asked them to make it go. And sure enough, 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 one is, again, remember, these are four year-olds. They’re just learning how to count. But unconsciously, they’re doing quite complicated calculations that will give them a conditional probability measure. And other interesting thing is that they’re using that evidence to to 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 that four year-olds are actually better at finding out unlikely hypothesis than adults are when we give them exactly the same task. So these circumstances, the children are using statistics to find out about 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 of interesting studies recently that have shown this playing around is really a of experimental research program. Here’s one from Cristine Legare’s lab. What Cristine was use our Blicket Detectors. And what she did was show children that yellow ones made go and red ones didn’t, and then she showed them an anomaly. And what you’ll see is this little boy will go through five hypotheses in the space of two minutes.
(Video) Boy: How this? Same as the other side.
Alison Gopnik: Okay, so his first has just been falsified.
(Laughter)
Boy: This one lighted up, and 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 be like this, and this needs to like this.
AG: Okay, hypothesis two.
Boy: That’s why. Oh.
(Laughter)
AG: Now this is his idea. He told the experimenter to do this, to try putting out onto the other location. Not working either.
Boy: Oh, because the 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 to make it up and two on this one to make it light up.
AG: Okay,there’s his hypothesis.
Now that is a particularly — that is particularly adorable and articulate little boy, but what Cristine discovered is is actually quite typical. If you look at the way children play, when you ask to explain something, what they really do is do a series of experiments. This is actually pretty of four year-olds.
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Well, what’s it like to be this kind of creature? What’s it to be one of these brilliant butterflies who can test five hypotheses two minutes? Well, if you go back to those psychologists and philosophers, a lot them have said that babies and young children were barely conscious if they were at all. And I think just the opposite is 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’ attention consciousness look kind of like a spotlight. So what happens for adults is we decide something’s relevant or important, we should pay attention to it. Our consciousness of thing that we’re attending to becomes extremely bright and vivid, and everything sort of goes dark. And we even know something the way the brain does this.
So what happens when pay attention is that the prefrontal cortex, the sort executive part of our brains, sends a signal that makes little part of our brain much more flexible, more plastic, at learning, and shuts down activity in all the of our brains. So we have 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 a lantern of than a spotlight of consciousness. So babies and young children are very at narrowing down to just one thing. But they’re very good taking in lots of information from lots of different sources at once. And you actually look in their brains, you see that they’re flooded with these neurotransmitters that are really good inducing learning and plasticity, and the inhibitory parts haven’t come on yet. So when we say babies and young children are bad at paying attention, what really mean is that they’re bad at not paying attention. So they’re bad at getting rid all the interesting things that could tell them something and looking at the thing that’s important. That’s the kind of attention, the of consciousness, that we might expect from those butterflies who designed to learn.
Well if we want to think a way of getting a taste of that kind of baby consciousness adults, I think the best thing is think about where we’re put in a new situation that we’ve never in before — when we fall in love with someone new, or we’re in a new city for the first time. And happens then is not that our consciousness contracts, it expands, that those three days in Paris seem to be full of consciousness and experience than all the months being a walking, talking, faculty meeting-attending zombie back home. And by the way, 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 the first time after you’ve had three double-espressos. (Laughter) That’s a fantastic way to be, it does tend to leave you waking up crying three o’clock in the morning.
(Laughter)
Now it’s good to be grownup. I don’t want to say too much about how babies are. It’s good to be a grownup. We can do things tie our shoelaces and cross the street by ourselves. And it makes sense that we put a lot effort 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 some of the time we should getting the adults to start thinking more like children.
(Applause)