What is going in this baby’s mind? If you’d asked people this 30 years ago, most people, including psychologists, have said that this baby was irrational, illogical, egocentric — he couldn’t take the perspective of another person or cause and effect. In the last 20 years, developmental has completely overturned that picture. So in some ways, we think that this baby’s is like the thinking of the most brilliant scientists.
Let me give you just one example this. One thing that this baby could be thinking about, that could be on in his mind, is trying to figure out what’s going on in the of that other baby. After all, one of the that’s hardest for all of us to do is to figure what other people are thinking and feeling. And maybe hardest thing of all is to figure out that what other people and feel isn’t actually exactly like what we think and feel. Anyone who’s followed politics can testify how hard that is for some people to get. We wanted know if babies and young children could understand this really profound about other people. Now the question is: How could we them? Babies, after all, can’t talk, and if you ask a three year-old tell you what he thinks, what you’ll get is a beautiful of consciousness monologue about ponies and birthdays and things that. So how do we actually ask them the question?
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Well turns out that the secret was broccoli. What we — Betty Rapacholi, who was one of my students, and I — was actually to give the babies 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 like raw broccoli. (Laughter) But then what Betty did was take a little taste of food from each bowl. And she would act as if she it or she didn’t. So half the time, she acted as if she the crackers and didn’t like the broccoli — just a baby and any other sane person. But half 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 of the crackers, and she’d go, “Eww, yuck, crackers. tasted the crackers. Eww, yuck.” So she’d act as if she wanted was just the opposite of what the babies wanted. We did this 15 and 18 month-old babies. And then she would simply put her hand out and say, “Can you me some?”
So the question is: What would the baby give her, they liked or what she liked? And the remarkable was that 18 month-old babies, just barely walking and talking, would give her the crackers if she the crackers, but they would give her the broccoli if she liked the broccoli. the other hand, 15 month-olds would stare at her for a long time if she acted as she liked the broccoli, like they couldn’t figure this out. But after they stared 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 already discovered this profound fact about human nature, that we don’t always the same thing. And what’s more, they felt that 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, fact about human nature in the three months from when they 15 months old. So children both know more and learn more than ever would have thought. And this is just one of and hundreds of studies over the last 20 years that’s demonstrated it.
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The question you might ask is: Why do children learn so much? And how is possible for them to learn so much in such a short time? I mean, after all, you look at babies superficially, they seem pretty useless. And actually in many ways, they’re 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 care useless babies, it turns out that there’s actually an answer. If we look across many, many different of animals, not just us primates, but also including mammals, birds, even marsupials like kangaroos and wombats, it out that there’s a relationship between how long a childhood a species has and big their brains are compared to their bodies and smart and flexible they are.
And sort of the posterbirds this idea are the birds up there. On one side is a New Caledonian crow. And crows and corvidae, ravens, rooks and so forth, are incredibly smart birds. They’re as smart as chimpanzees some respects. And this is a bird on the cover of science who’s learned to use a tool to get food. On the other hand, we have our friend the domestic chicken. chickens and ducks and geese and turkeys are basically as as dumps. So they’re very, very good at pecking grain, and they’re not much good at doing anything else. Well it turns out the babies, the New Caledonian crow babies, are fledglings. They depend on their moms to worms in their little open mouths for as long as two years, is a really long time in the life of a bird. 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 childhood that seems to be connected to knowledge and learning. Well what kind of explanation we have for this? Well some animals, like the chicken, to be beautifully suited to doing just one thing well. So they seem to be beautifully suited to pecking in one environment. Other creatures, like the crows, aren’t very at doing anything in particular, but they’re extremely good at about laws of different environments.
And of course, we human are way out on the end of the distribution like crows. We have bigger brains relative to our bodies far than any other animal. We’re smarter, we’re more flexible, we learn more, we survive in more different environments, we migrated to cover the world and go to outer space. And our babies and children are dependent on us for much longer the babies of any other species. My son is 23. (Laughter) And at least they’re 23, we’re still popping those worms into those little mouths.
All right, why would we see this correlation? an idea is that that strategy, that learning strategy, is an extremely powerful, great strategy for getting on the world, but it has one big disadvantage. And that one big disadvantage is that, until actually do all that learning, you’re going to be helpless. So you don’t want 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 actually show up. And the way the evolutions seems to have solved problem is with a kind of division of labor. So the idea is that have this early period when we’re completely protected. We don’t to 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 children and actually put them to work to do things out in the world.
So one way of thinking about is that babies and young children are like the research and development division of the species. So they’re the protected blue sky guys who just have to go and learn and have good ideas, and we’re production and marketing. We to take all those ideas that we learned when we were children and actually put them use. Another way of thinking about it is instead thinking of babies and children as being like defective grownups, we should about them as being a different developmental stage of the same — kind of like caterpillars and butterflies — except that they’re actually the brilliant butterflies who flitting around the garden and exploring, and we’re the caterpillars 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 story would children are for learning, that’s what they’re for — we might expect they would have really powerful learning mechanisms. And in fact, baby’s brain seems to be the most powerful learning on the planet. But real computers are actually getting to be lot better. And there’s been a revolution in our of machine learning recently. And it all depends on 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 out about the world. what scientists do is they have a hypothesis that they might be likely to start with. They go out test it against the evidence. The evidence makes them that hypothesis. Then they test that new hypothesis and so on so forth. And what Bayes showed was a mathematical that you could do that. And that mathematics is at core of the best machine learning programs that we have now. And some 10 ago, I suggested that babies might be doing the same thing.
So you want to know what’s going on underneath those beautiful brown eyes, I think it actually looks something this. This is Reverend Bayes’s notebook. So I think those babies are actually making 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 actually demonstrate. Because after all, if you ask even grownups about statistics, they look extremely stupid. could it be that children are doing statistics?
So to test we used a machine that we have called the Blicket Detector. is a box that lights up and plays music when you put some things on 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 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 to begin with that the way to make the detector go would be to put a block top of the detector. But actually, this detector works in bit of a strange way. Because if you wave a block over top of the detector, something you wouldn’t ever think to begin with, the detector will actually activate two of three times. Whereas, if you do the likely thing, put the block on the detector, it will activate two out of six times. So the unlikely 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, we just asked them to make it go. And sure enough, the year-olds used the evidence to wave the object on top of detector.
Now there are two things that are really interesting this. The first one is, again, remember, these are four year-olds. They’re learning how to count. But unconsciously, they’re doing these complicated calculations that will give them a conditional probability measure. And the interesting thing is that they’re using that evidence to get an idea, get to a hypothesis about the world, seems very unlikely to begin with. And in studies we’ve just been in my lab, similar studies, we’ve show that four year-olds are actually better at finding out an unlikely hypothesis adults are when we give them exactly the same task. So in these circumstances, the children are using 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 everything” or else “playing.”
And there’s been a bunch of 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 did was use our Blicket Detectors. And she did was show children that yellow ones made it go and red ones didn’t, then she showed them an anomaly. And what you’ll is that this little boy will go through five in the space of two minutes.
(Video) Boy: How about this? Same as other side.
Alison Gopnik: Okay, so his first hypothesis has been falsified.
(Laughter)
Boy: This one lighted up, and this 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 that expression 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 a fourth hypothesis.
Boy: It’s up. So when you put four. So you put four on this one to make it light up two on this one to make it light up.
AG: Okay,there’s fifth hypothesis.
Now that is a particularly — that is particularly adorable and articulate little boy, but what Cristine is this is actually quite typical. If you look at the children play, when you ask them to explain something, what they do is do a series of experiments. This is pretty 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 five hypotheses two minutes? Well, if you go back to those psychologists philosophers, a lot of them have said that babies young children were barely conscious if they were conscious all. And I think just the opposite is true. I think babies and are actually more conscious than we are as adults. Now here’s we know about how adult consciousness works. And adults’ attention and look kind of like a spotlight. So what happens for is we decide that something’s relevant or important, we pay attention to it. Our consciousness of that thing that we’re attending to becomes extremely bright vivid, and everything else sort of goes dark. And we even know about the way the brain does this.
So what happens when pay attention is that the prefrontal cortex, the sort of executive of our brains, sends a signal that makes a little part of our much more flexible, more plastic, better at learning, and shuts activity in all the rest of our brains. So have a very focused, purpose-driven kind of attention. If look at babies and young children, we see something different. I think babies and young children seem to have more of a of consciousness than a spotlight of consciousness. So babies and young children are very at narrowing down to just one thing. But they’re very good at in lots of information from lots of different sources at once. And if actually look in their brains, you see that they’re with these neurotransmitters that are really good at inducing and plasticity, and the inhibitory parts haven’t come on yet. when we say that babies and young children are bad at paying attention, what we really mean that they’re bad at not paying attention. So they’re bad 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 if we want to think about way of getting a taste of that kind of consciousness as adults, I think the best thing is about cases where we’re put in a new situation that we’ve been in before — when we fall in love with someone new, when we’re in a new city for the first time. And what happens is not that our consciousness contracts, it expands, so those three days in Paris seem to be more full 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 effect of those baby neurotransmitters. So what’s it like to be a baby? It’s like being love in Paris for the first time after you’ve had three double-espressos. (Laughter) That’s a fantastic way be, but it does tend to leave you waking up at three o’clock in the morning.
(Laughter)
Now it’s to be a grownup. I don’t want to say much about how wonderful babies are. It’s good to a grownup. We can do things like tie our shoelaces and cross street by ourselves. And it makes sense that we put a lot of effort into 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 time we should be getting the adults to start thinking more children.
(Applause)