What is going on 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 perspective of another person understand cause and effect. In the last 20 years, developmental science has overturned 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 of this. One thing that this baby could be about, that could be going on in his mind, is to figure out what’s going on in the mind of other baby. After all, one of the things that’s hardest for all of us to do is figure out what other people are thinking and feeling. And maybe the hardest thing of all is to out that what other people think and feel isn’t actually exactly what we think and feel. Anyone who’s followed politics testify to how hard that is for some people to get. We to know if babies and young children could understand this really profound thing about people. Now the question is: How could we ask them? Babies, all, can’t talk, and if you ask a three year-old to tell what he thinks, what you’ll get is a beautiful stream of consciousness about ponies and birthdays and things like that. So how do we ask them the question?
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Well it turns out that the secret broccoli. What we did — Betty Rapacholi, who was of my students, and I — was actually to the babies two bowls of food: one bowl of broccoli and one bowl of delicious goldfish crackers. Now all of the babies, even in Berkley, like crackers and don’t like the raw broccoli. (Laughter) But then Betty did was to take a little taste of from each bowl. And she would act as if liked it or she didn’t. So half the time, she acted as she liked the crackers and didn’t like the broccoli — just a 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 bit of the crackers, and she’d go, “Eww, yuck, crackers. I tasted the crackers. Eww, yuck.” she’d act as if what she wanted was just opposite of what the babies wanted. We did this with 15 and 18 month-old babies. then she would simply put her hand 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 thing that 18 month-old babies, just barely walking and talking, would her the crackers if she liked the crackers, but would give her the broccoli if she liked the broccoli. On the hand, 15 month-olds would stare at her for a long time she acted as if she liked the broccoli, like they couldn’t figure this out. then after they stared for a long time, they would just give her crackers, what they thought everybody must like. So there are really remarkable things about this. The first one is that these little 18 month-old babies already discovered this really profound fact about human nature, that we don’t always want same thing. And what’s more, they felt that they should actually do to help other people get what they wanted.
Even more remarkably though, the fact 15 month-olds didn’t do this suggests that these 18 month-olds had learned this deep, profound fact about nature in the three months from when they were 15 months old. So both know more and learn more than we ever would have thought. And this is just one hundreds and hundreds of studies over the last 20 that’s actually demonstrated it.
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The question you ask though is: Why do children learn so much? And how is it possible for them to 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 time energy into just keeping them alive. But if we turn to evolution an answer to this puzzle of why we spend so much time care of useless babies, it turns out that there’s actually answer. If we look across many, many different species animals, not just 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 a species has how big their brains are compared to their bodies how smart and flexible they are.
And sort of posterbirds for this idea are the birds up there. On side is a New Caledonian crow. And crows and corvidae, ravens, rooks and so forth, are incredibly smart birds. They’re as as chimpanzees in some respects. And this is a bird on the of science who’s learned how to use a tool get food. On the other hand, we have our friend the domestic chicken. And and ducks and geese and turkeys are basically as dumb as dumps. So they’re very, very at pecking for grain, and they’re not much good doing anything else. Well it turns out that the babies, New Caledonian crow babies, are fledglings. They depend on moms to drop worms in their little open mouths as long as two years, which is a really long time the life of a bird. Whereas the chickens are mature within a couple of months. So childhood is reason why the crows end up on the cover Science 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 some animals, like the chicken, seem be beautifully suited to doing just one thing very well. So they seem to be suited 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 laws of different environments.
And of course, we human beings are way out on the end the distribution like the crows. We have bigger brains relative to our bodies by far than other animal. We’re smarter, we’re more flexible, we can more, we survive in more different environments, we migrated cover the world and even go to outer space. And babies and 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 popping those into those little open mouths.
All right, why would we see this correlation? Well an idea is that strategy, that learning strategy, is an extremely powerful, great strategy for getting on in world, but it has one big disadvantage. And that big disadvantage is that, until you actually do all learning, you’re going to be helpless. So you don’t want have the mastodon charging at you and be saying 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. And the way the seems to have solved that problem is with a kind division of labor. So the idea is that we have this early period we’re completely protected. We don’t have to do anything. All have to do is learn. And then as adults, we can take those things that we learned when we were babies and and actually put them to work to do things there in the world.
So one way of thinking about it is that babies and young are like the research and development division of the human species. they’re the protected blue sky guys who just have to out and 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 put them to use. Another way of thinking about it is instead of thinking of babies and as being like defective grownups, we should think about 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, path.
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If this is true, if these are designed to learn — and this evolutionary story would say children are for learning, that’s they’re for — we might expect that they would have really learning mechanisms. And in fact, the baby’s brain seems to be the powerful learning computer on the planet. But real computers are actually to be a lot better. And there’s been a revolution our understanding of machine learning recently. And it all depends on the ideas of this guy, Reverend Thomas Bayes, who was a statistician and mathematician the 18th century. And essentially what Bayes did was to provide a mathematical way probability theory to characterize, describe, the way that scientists find out the world. So what scientists do is they have a that they think might be likely to start with. They go and test it 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 could do that. And that mathematics is at the core of the best learning programs that we have now. And some 10 years ago, I that babies might be doing the same thing.
So 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 those babies are actually making complicated calculations with conditional probabilities that they’re revising figure out how the world works. All right, now that might seem like an even order to actually demonstrate. Because after all, if you ask even grownups about statistics, they extremely stupid. How could it be that children are doing statistics?
So to test this used a machine that we have called the Blicket Detector. This is a box that lights up plays music when you put some things on it and not others. And this very simple machine, my lab and others have dozens of studies showing just how good babies are at about the world. Let me mention just one that we with Tumar Kushner, my student. If I showed you this detector, you would be likely to think 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 a bit of a strange way. Because if you wave block over the top of the detector, something you wouldn’t ever think of to begin with, the will actually activate two out of three times. Whereas, if you do the thing, put the block on the detector, it will only activate two out of six times. the unlikely hypothesis actually has stronger evidence. It looks if the waving is a more effective strategy than the other strategy. So we just this; we gave four year-olds this pattern of evidence, and 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 interesting this. The first one is, again, remember, these are year-olds. They’re just learning how to count. But unconsciously, they’re doing these complicated calculations that will give them a conditional probability measure. And the other interesting thing is that they’re using evidence to get to an idea, get to a hypothesis about the world, that 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 finding out an unlikely hypothesis than adults are when we give them exactly the task. So in these circumstances, the children are using statistics to find 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 into everything” else “playing.”
And there’s been a bunch of interesting recently that have shown this playing around is really a kind of experimental program. Here’s one from Cristine Legare’s lab. What Cristine did was use our Blicket Detectors. And what did was show children that yellow ones made it go and red didn’t, and then she showed them an anomaly. And what you’ll is that this little boy will go through five hypotheses in the space of two minutes.
(Video) Boy: about 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 will recognize that expression of despair.
(Laughter)
Boy: Oh, it’s because this needs be like this, and this needs to be like this.
AG: Okay, two.
Boy: That’s why. Oh.
(Laughter)
AG: Now this is next idea. He told the experimenter to do this, try putting it 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 up. So when you put four. So you put four on this one to make it light and two on this one to make it light up.
AG: Okay,there’s his fifth hypothesis.
Now that a particularly — that is a particularly adorable and articulate little boy, but what discovered is this is actually quite typical. If you look at the way play, when you ask them to explain something, what they really do do a series of experiments. This is actually pretty of four year-olds.
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Well, what’s it like be this kind of creature? What’s it like to be of these brilliant butterflies who can test five hypotheses in minutes? Well, if you go back to those psychologists and philosophers, lot of them have said that babies and young children barely conscious if they were conscious at all. And I think the opposite is true. I think babies and children are actually more conscious than we are adults. Now here’s what we know about how adult consciousness works. And adults’ attention and consciousness look kind like a spotlight. So what happens for adults is we decide that something’s relevant or important, we 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. we even know something about the way the brain this.
So what happens when we pay attention is that prefrontal cortex, the sort of executive part of our brains, sends signal that makes a little part of our brain more flexible, more plastic, better at learning, and shuts down in all the rest of our brains. So we have a focused, purpose-driven kind of attention. If we look at babies young children, we see something very different. I think babies and young children seem to have of a lantern of consciousness than a spotlight of consciousness. babies and young children are very bad at narrowing down to just thing. But they’re very good at taking in lots of information from of different sources at once. And if you actually look in brains, you see that they’re flooded with these neurotransmitters are really good at inducing learning and plasticity, and inhibitory parts haven’t come on yet. So when we that babies and young children are bad at paying attention, what we mean is that they’re bad at not paying attention. they’re bad at 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 about a way of getting a taste of that kind of baby as adults, I think the best thing is think about cases we’re put in a new situation that we’ve never been in — when we fall in love with someone new, or when we’re a new city for the first time. And what happens then is not our consciousness contracts, it expands, so that those three days in Paris to be more full of consciousness and experience than the months of being a walking, talking, faculty meeting-attending zombie back home. by the way, that coffee, that wonderful coffee you’ve been drinking downstairs, actually the effect of those baby neurotransmitters. So what’s it like to be baby? It’s like being in love in Paris for first time after you’ve had three double-espressos. (Laughter) That’s a fantastic way to be, but it tend to leave you waking 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 how wonderful babies are. It’s good to be a grownup. We do things like tie our shoelaces and cross the by ourselves. And it makes sense that we put a lot of 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 the time we should be getting the adults to start thinking more children.
(Applause)