What is on in this baby’s mind? If you’d asked people this 30 years ago, people, including psychologists, would have said that this baby irrational, illogical, egocentric — that he couldn’t take the of another person or understand cause and effect. In last 20 years, developmental science has completely overturned that picture. in some ways, we think that this baby’s thinking like the thinking of the most brilliant scientists.
Let give you just one example of this. One thing this baby could be thinking about, that could be going on in his mind, trying to figure out what’s going on in the mind of that other baby. After all, of the things that’s hardest for all of us to do to figure out what other people are thinking and feeling. And the hardest thing of all is to figure out that what other think and feel isn’t actually exactly like what we think and feel. Anyone who’s politics can testify to how hard that is for people to get. We wanted to know if babies and young could understand this really profound thing about other people. Now the question is: How we ask them? Babies, after all, can’t talk, and if you ask a three year-old to you what he thinks, what you’ll get is a beautiful stream of consciousness monologue about ponies birthdays and things like that. So how do we ask them the question?
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Well it turns out that the secret was broccoli. we did — Betty Rapacholi, who was one of students, and I — was actually to give the two bowls of food: one bowl of raw broccoli and one bowl delicious goldfish crackers. Now all of the babies, even in Berkley, like the crackers and don’t like the broccoli. (Laughter) But then what Betty did was to take a little taste food from each bowl. And she 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 like the broccoli — just like baby and any other sane person. But half the time, what she would do is take little bit of the broccoli and go, “Mmmmm, broccoli. I tasted 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 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 question is: What 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, would her the crackers if she liked the crackers, but they 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 as if she liked broccoli, like they couldn’t figure this out. But then after they stared for a long time, they would give her the crackers, what they thought everybody must like. So there are really remarkable things about this. The first one is these little 18 month-old babies have already discovered this profound fact about human nature, that we don’t always want the same thing. And what’s more, felt that they should actually do things to help other people get what wanted.
Even more remarkably though, the fact that 15 month-olds didn’t this suggests that these 18 month-olds had learned this deep, profound fact about human in the three months from when they were 15 months old. So children both more and learn more than we ever would have thought. And this is one of hundreds and hundreds of studies over the 20 years that’s actually demonstrated it.
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The question you ask though is: Why do children learn so much? And how is possible for them to learn so much in such a short time? I mean, all, if you look at babies superficially, they seem useless. And actually in many ways, they’re worse than useless, because we have to put so much and energy into just keeping them alive. But if we turn to evolution an answer to this puzzle of why we spend so much time taking of useless babies, it turns out that there’s actually an answer. we look across many, many different species of animals, 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 and how and flexible they are.
And sort of the posterbirds for this idea are birds up there. On one side is a New crow. And crows and other corvidae, ravens, rooks and forth, are incredibly smart birds. They’re as smart as in some respects. And this is a bird on the cover science who’s learned how to use a tool to get food. On the other hand, we have friend the domestic chicken. And chickens and ducks and geese and are basically as dumb as dumps. So they’re very, very good at for grain, and they’re not much good at doing anything else. Well it turns out that the babies, New Caledonian crow babies, are fledglings. They depend on their moms to drop worms in their little open for as long as two years, which is a really long time the life of a bird. Whereas the chickens are actually mature within a couple of months. So childhood the reason why the crows end up on the cover Science and the chickens end up in the soup pot.
There’s something about long childhood that seems to be connected to knowledge and learning. Well what kind explanation could we have for this? Well some animals, like the chicken, seem be beautifully suited to doing just one thing very well. they seem to be beautifully suited to pecking grain in one environment. Other creatures, like crows, aren’t very good at doing anything in particular, but they’re extremely good learning about laws of different environments.
And of course, we human beings are out on the end of the distribution like the crows. have bigger brains 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, migrated to cover the world and even go to space. And our babies and children are dependent on for much longer than the babies of any other species. My is 23. (Laughter) And at least until they’re 23, we’re popping those worms into those little open mouths.
All right, would we see this correlation? Well an idea is that that strategy, that learning strategy, is an powerful, great strategy for getting on in the world, but it one big disadvantage. And that one big disadvantage is that, until you do all that learning, you’re going to be helpless. So don’t want to have the mastodon charging at you and be saying to yourself, “A or maybe a spear might work. Which would actually better?” You want to know all that before the mastodons actually up. And 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 do anything. All we have to do is learn. And then as adults, can take all those things that we learned when we were babies and and actually put them to work to do things out there in world.
So one way of thinking about it is that babies and young children like the research and development division of the human species. So they’re the protected blue sky who just have to go out and learn and good ideas, and we’re production and marketing. We have to take all those that we learned when we were children and actually put them to use. Another way of thinking it is instead of thinking of babies and children being like defective grownups, we should think about them as being a different developmental stage of the 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 along our 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 learning, that’s what they’re for — we might expect they would have really powerful learning mechanisms. And in fact, the baby’s brain seems to the most powerful learning computer on the planet. But real are actually getting to be a lot better. And there’s been revolution in our understanding of machine learning recently. And it depends on the ideas of this guy, the Reverend Thomas Bayes, who a statistician and mathematician in the 18th century. And what Bayes did was to provide a mathematical way 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. They go out and test against the evidence. The evidence makes them change that hypothesis. Then they test that new and so on and so forth. And what Bayes showed was a mathematical way that you do that. And that mathematics is at the core of the best machine learning programs 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 it actually 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 out how the world works. All right, now that might seem like an even taller order to demonstrate. Because after all, if you ask even grownups about statistics, they look extremely stupid. How could be that children are doing statistics?
So to test this we used a machine that we have the Blicket Detector. This is a box that lights up plays music when you put some things on it and others. And using this very simple machine, my lab and others have done of studies showing just how good babies are at learning the world. Let me mention just one that we did with Tumar Kushner, student. If I showed you this detector, you would be likely to think begin with that the way to make the detector go be to put a block on top of the detector. But actually, this detector in a bit of a strange way. Because if wave a block over the top of the detector, you wouldn’t ever think of to begin with, the detector will actually activate two 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 we did just this; we gave four year-olds this of evidence, and we just asked them to make it go. And sure enough, the four year-olds 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 four year-olds. They’re just learning how count. But unconsciously, they’re doing these quite complicated calculations that will give them conditional probability measure. And the other interesting thing is they’re using that evidence to get to an idea, get to a hypothesis the world, that seems very unlikely to begin with. And in 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 when we them exactly the same task. So in these circumstances, children are using statistics to find out about the world, but after all, scientists also do experiments, and we to see if children are doing experiments. When children do experiments we call “getting into everything” or else “playing.”
And there’s been bunch of interesting studies recently that have shown this playing is really a kind of experimental research program. Here’s one from Cristine Legare’s lab. What Cristine was use our Blicket Detectors. And what she did was children that yellow ones made it go and red ones didn’t, and then she them an anomaly. And what you’ll see is that this little boy will go through five 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, this one nothing.
AG: Okay, he’s got his experimental out.
Boy: What’s making this light up. (Laughter) I don’t know.
AG: Every scientist will recognize that expression 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. He the experimenter to do this, to try putting it out the other location. Not working either.
Boy: Oh, because the light only to here, not here. Oh, the bottom of this has electricity in here, but this doesn’t have electricity.
AG: Okay, that’s fourth hypothesis.
Boy: It’s lighting up. So when you four. So you put four on this one to make it light up and two on this one make it light up.
AG: Okay,there’s his fifth hypothesis.
Now is a particularly — that is a particularly adorable and little boy, but what Cristine discovered is this is actually quite typical. If you look the way children play, when you ask them to explain something, what they do is do a series of experiments. This is actually typical of four year-olds.
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Well, what’s it to be this kind of creature? What’s it like be one of these brilliant butterflies who can test hypotheses in two minutes? Well, if you go back 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 just the opposite is true. I think babies and children are more conscious than we are as adults. Now here’s what we know about how adult consciousness works. adults’ attention and consciousness look kind of like a spotlight. So happens for adults is we decide that something’s relevant important, we should pay attention to it. Our consciousness that thing that we’re attending to becomes extremely bright vivid, and everything else sort of goes dark. And we even know something about the the brain does this.
So what happens when we pay is that the prefrontal cortex, the sort of executive 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 attention. If we look at babies and young children, we see something very different. I think babies young children seem to have more of a lantern of consciousness a spotlight of consciousness. So babies and young children very bad at narrowing down to just one thing. But they’re very good at in lots of information from lots of different sources once. And if you actually look in their brains, you that they’re flooded with these neurotransmitters that are really 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, what we really is that they’re bad at not paying attention. So they’re bad getting rid of all the interesting things that could tell something 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 if want to think about a way of getting a of that kind of baby consciousness as adults, I the best thing is think about cases where we’re put in new situation that we’ve never been in before — when we fall in with someone new, or when we’re in a new city for the first time. And happens then is not that our consciousness contracts, it expands, so that those three days in Paris seem to more full of consciousness and experience than all the months of being 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 to be, but it does tend to leave you up crying at three o’clock in the morning.
(Laughter)
Now it’s good be a grownup. I don’t want to say too much about how wonderful babies are. It’s to be a grownup. We can do things like our shoelaces and cross the street by ourselves. And it makes sense that put a lot of effort into making babies think like adults do. But what we want is to be like those butterflies, 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)