What is going in this baby’s mind? If you’d asked people this 30 ago, most people, including psychologists, would have said that this was irrational, illogical, egocentric — that he couldn’t take the of another person or understand cause and effect. In the last 20 years, developmental science has completely that picture. So in some ways, we think that this baby’s thinking is like the thinking of most brilliant scientists.
Let me give you just one example this. One thing that this baby could be thinking about, that could be going in his mind, is trying to figure out what’s going on in the mind of that baby. After all, one of the things that’s hardest for all of us do is to figure out what other people are thinking and feeling. And maybe the hardest thing of is to figure out that what other people think and feel isn’t actually exactly like what think and feel. Anyone who’s followed politics can testify to how hard that is for some people get. We wanted to know if babies and young children understand this really profound thing about other people. Now the question is: How could we them? Babies, after all, can’t talk, and if you a three year-old to tell you what he thinks, you’ll get is a beautiful stream of consciousness monologue about ponies birthdays and things like that. So how do we actually ask the question?
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Well it turns out that the secret was broccoli. What did — Betty 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 and don’t the raw broccoli. (Laughter) But then what Betty did was to take a little taste of from each bowl. And she would act as if she liked it or she didn’t. So the time, she acted as if she liked the crackers and didn’t like the broccoli — like a baby and any other sane person. But half the time, she would do is take a little bit of the broccoli and go, “Mmmmm, broccoli. I the broccoli. Mmmmm.” And then she would take a little bit of the crackers, she’d go, “Eww, yuck, crackers. I tasted the crackers. Eww, yuck.” So she’d act as if she wanted was just the opposite of what the babies wanted. did this with 15 and 18 month-old babies. And then 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? the remarkable thing was that 18 month-old babies, just walking and talking, would give her the crackers if she liked the crackers, but would give her the broccoli if she liked the broccoli. On other hand, 15 month-olds would stare at her for a long if she acted as if she liked the broccoli, they couldn’t figure this out. But then after they stared for a time, they would just give her the crackers, what they thought must like. So there are two really remarkable things about this. The one is that these little 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 actually things to help other people get what they wanted.
Even remarkably though, the fact that 15 month-olds didn’t do suggests that these 18 month-olds had learned this deep, profound fact human nature in the three months from when they 15 months old. So children both know more and learn more we ever would have thought. And this is just one of hundreds and hundreds of studies over last 20 years that’s actually demonstrated it.
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The question you might ask though is: Why children learn so much? And how is it possible for to learn so much in such a short time? I mean, after all, if you at babies superficially, they seem pretty useless. And actually many ways, they’re worse than useless, because we have put so much time and energy into just keeping them alive. But we turn to evolution for an answer to this puzzle of why spend so much time taking care of 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, it turns out there’s a relationship between how long a childhood a species has and how big their brains are to their bodies and how smart and flexible they are.
And sort the posterbirds for this idea are the birds up there. one side is a 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 a bird the cover of science who’s learned how to use tool to get food. On the other hand, we our friend the domestic chicken. And chickens and ducks and geese and turkeys are as dumb as dumps. So they’re very, very good at pecking for grain, and they’re not much good doing anything else. Well it turns out that the babies, the New Caledonian crow babies, are fledglings. They depend their moms to drop worms in their little open mouths for long as two years, which is a really long in the life of a bird. Whereas the chickens actually mature within a couple of months. So childhood the reason why the crows end up on the cover of Science and the end up in the soup pot.
There’s something about that long childhood that to be connected to knowledge and learning. Well what kind of could we have for this? Well some animals, like chicken, seem to be beautifully suited to doing just one very well. So they seem to be beautifully suited to pecking grain in environment. Other creatures, like the crows, aren’t very good at anything in particular, but they’re extremely good at learning about laws of different environments.
And 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, can learn more, we survive in more different environments, we migrated to cover the world even go to outer space. And our babies and children are on us for much longer than the babies of any species. My son is 23. (Laughter) And at least until they’re 23, we’re popping those worms into those little open mouths.
All right, why we see this correlation? Well an idea is that that strategy, that strategy, is an extremely powerful, great strategy for getting on the world, but it has one big disadvantage. And that one big disadvantage that, until you actually do all that learning, you’re going to helpless. So you don’t want to have the mastodon at you and be saying to yourself, “A slingshot maybe a spear might work. Which would actually be better?” You want to know all before the mastodons actually show up. And the way the evolutions seems to have solved problem is with a kind of division of labor. the idea is that we have this early period we’re completely protected. We don’t have to do anything. All we have do is learn. And then as adults, we can all those things that we learned when we were and children and actually put them to work to do things out there in 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 protected blue sky guys who just have to go and learn and have good ideas, and we’re production and marketing. We have to take those ideas that we learned when we were children and put them to use. Another way of thinking about it is instead of of babies and children as being like defective grownups, we should think about them as being different developmental stage of the same species — kind of like caterpillars and — except that they’re actually the 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 evolutionary would say children are for learning, that’s what they’re for — we might that they would have really powerful learning mechanisms. And fact, the baby’s brain seems to be the most learning computer on the planet. But real computers are actually getting be a lot better. And there’s been a revolution in our understanding machine learning 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 theory characterize, describe, the way that scientists find out about the world. So what scientists do is have 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 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 at the core the 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 to what’s going on underneath those beautiful brown eyes, I think actually looks something like this. This is Reverend Bayes’s notebook. So I think those babies 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 even order to actually demonstrate. Because after all, if you ask grownups about statistics, they look extremely stupid. How could it be that children are doing statistics?
So test this we used a machine that we have called the Detector. This is a box that lights up and plays when you put some things on it and not others. And using this very simple machine, my lab others have done dozens of studies showing just how good babies are at about the world. Let me mention just one that we did with Tumar Kushner, my student. I showed you this detector, you would be likely to think to with that the way to make the detector go would to put a block on top of the detector. But actually, this works in a bit of a strange way. Because you wave a block over the top of the detector, something wouldn’t ever think of to begin with, the detector will actually two out of three times. Whereas, if you do the likely thing, put the block 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 did just this; we gave four year-olds this pattern of evidence, and we just asked them make it go. And sure enough, the four year-olds used the evidence wave the object on top of the detector.
Now there two things that are really interesting about this. The one is, again, remember, these are four year-olds. They’re just learning to count. But unconsciously, they’re doing these quite complicated 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 to begin with. And in studies we’ve just been doing my lab, similar studies, we’ve show that four year-olds are better at finding out an unlikely hypothesis than adults are we give them exactly the same task. So in these circumstances, the are using statistics to find out about the world, but 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 interesting studies recently that 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 made it go and red ones didn’t, and then showed them an anomaly. And what you’ll see is 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 hypothesis has been 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 this, and this needs to be like this.
AG: Okay, hypothesis two.
Boy: That’s why. Oh.
(Laughter)
AG: this is his next idea. He told the experimenter to do this, to try it out onto the other location. Not working either.
Boy: Oh, because the light only to here, not here. Oh, the bottom of box has electricity in here, but this doesn’t have electricity.
AG: Okay, that’s fourth hypothesis.
Boy: It’s lighting up. So when you put four. So you four on this one to 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 — that is a particularly and articulate little boy, but what Cristine discovered is is actually 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 pretty typical four year-olds.
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Well, what’s it like to be this kind creature? What’s it like to be one of these brilliant butterflies can test five hypotheses in two minutes? Well, if go back to those psychologists and philosophers, a lot of them have said that and young children were barely conscious if they were conscious at all. And think just the opposite is true. I think babies and children actually more conscious than we are as adults. Now here’s what we about how adult consciousness works. And adults’ attention and look kind of like a spotlight. So what happens for adults is decide that something’s relevant or important, we should pay attention it. Our consciousness of that thing that we’re attending becomes 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 attention is that the prefrontal cortex, sort of executive part of our brains, sends a signal that makes a part of our brain much more flexible, more plastic, better 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 to more of a lantern of consciousness than a spotlight consciousness. So babies and young children are very bad narrowing down to just one thing. But they’re very at taking in lots of information from lots of different sources at once. And if actually look in their brains, you see that they’re flooded these neurotransmitters that are really good at inducing learning plasticity, and the inhibitory parts haven’t come on yet. when we say that babies and young children are at paying attention, what we really mean is that they’re bad not paying attention. So they’re bad at getting rid of the interesting things that could tell them something and just looking 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 about a way getting a taste of that kind of baby consciousness 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 a new for the first time. And what happens then is not that consciousness contracts, it expands, so that those 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 home. And by the way, that coffee, that wonderful coffee you’ve been downstairs, actually mimics the effect of those baby neurotransmitters. So what’s it like to 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 up crying at three o’clock in the morning.
(Laughter)
Now it’s good to a grownup. I don’t want to say too much about how wonderful babies are. It’s good to be grownup. We can do things like tie our shoelaces and cross the by ourselves. And it makes sense that we put a lot of effort making babies think like adults do. But if what we want is to be like those butterflies, have open-mindedness, open learning, imagination, creativity, innovation, maybe at least some of the time should be getting the adults to start thinking more children.
(Applause)