What going on in this baby’s mind? If you’d asked this 30 years ago, most people, including psychologists, would 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 science completely overturned that picture. So in some ways, we that this baby’s thinking is like the thinking of the most brilliant scientists.
Let me give you one example of this. One thing that this baby could thinking about, that could be going on in his mind, is trying to out what’s going on in the mind of that other baby. After all, one the things that’s hardest for all of us to do is figure out what other people are thinking and feeling. maybe the hardest thing of all is to figure out that what people think and feel isn’t actually exactly like what we think and feel. Anyone who’s followed politics can to how hard that is for some people to get. We wanted to know if and young children could understand this really profound thing other people. Now the question is: How could we ask them? Babies, after all, can’t talk, and if 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 that. So how do we actually ask them the question?
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it turns out that the secret was broccoli. What we — Betty Rapacholi, who was one of my students, and I — actually to give the babies 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 the raw broccoli. (Laughter) But then what Betty did was to 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 the and didn’t like the broccoli — just like a and any other sane person. But half the time, what she do is take a little bit of the broccoli go, “Mmmmm, broccoli. I tasted the broccoli. Mmmmm.” And then she would take little bit of 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 of the babies wanted. We did this with 15 and 18 month-old babies. And then she would simply her hand out and say, “Can you give me some?”
So the question is: What would baby give her, what they liked or what she liked? the remarkable thing was that 18 month-old babies, just barely walking and talking, would her the crackers if she liked the crackers, but they would give the broccoli if she liked the broccoli. On the hand, 15 month-olds would stare at her for a long time if acted as if she liked the broccoli, like they couldn’t figure this out. But then after they for a long time, they would just give her the crackers, they thought everybody must like. So there are two really remarkable about this. The first one is that these little 18 month-old babies have already discovered really 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 what they wanted.
Even more remarkably though, the fact that 15 month-olds didn’t do this that these 18 month-olds had learned this deep, profound fact about human nature in the three from when they were 15 months old. So children both know more and learn more than ever would have thought. And this is just one of hundreds 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 it possible for them to learn so in such a short time? I mean, after all, if look at babies superficially, they seem pretty useless. And in many ways, they’re worse than useless, because we have to put so much time and energy into keeping them alive. But if we turn to evolution for an answer to this puzzle of we spend so much time taking care of useless babies, it turns out that there’s an answer. If 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 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 the posterbirds for this idea are the birds there. On one side is a New Caledonian crow. And crows other 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 to get food. On the other hand, have our friend the domestic chicken. And chickens and ducks and geese and are basically as dumb as dumps. So they’re very, good at pecking for grain, and they’re not much good at doing else. Well it turns out that the babies, the New Caledonian crow babies, are fledglings. depend on their moms to drop worms in their little mouths for as long as two years, which is a really time in the life of a bird. Whereas the chickens are actually mature within couple of months. So childhood is the reason why crows end up on the cover of Science and chickens end up in the soup pot.
There’s something about that childhood that seems to be connected to knowledge and learning. Well what of explanation could we have for this? Well some animals, like the chicken, seem to be suited to doing just one thing very well. So seem to be beautifully suited to pecking grain in one environment. Other creatures, the crows, aren’t very good at doing anything in particular, but they’re extremely good at learning laws of different environments.
And of course, we human beings are out on the end of the distribution like the crows. We have bigger brains relative our bodies by far than any other animal. We’re smarter, we’re flexible, we can learn more, we survive in more environments, we migrated to cover the world and even to outer space. And our babies and children are dependent on us for much longer than babies of any other species. My son is 23. (Laughter) And at least they’re 23, we’re still popping those worms into those open 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, you actually do all that learning, you’re going to be helpless. So you don’t want to have mastodon charging at you and be saying to yourself, “A or maybe a spear might work. Which would actually be better?” You want know all that before the mastodons actually show up. And way the evolutions seems to have solved that problem with a kind of division of labor. So the is that we have this early period when we’re completely protected. We don’t have to anything. All we have to do is learn. And then as adults, we can take those things that we learned when we were babies and children and actually put to work to do things out there in the world.
So one way thinking about it is that babies and young children like the research and development division of the human species. So they’re the blue sky guys who just have to go out and learn and have ideas, and we’re production and marketing. We have to take all those ideas we learned when we were children and actually put 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 a different stage of the same species — kind of like caterpillars butterflies — except that they’re actually the brilliant butterflies are flitting around the garden and exploring, and we’re 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 story would say children are for learning, that’s what they’re for — we might expect that they would have powerful learning mechanisms. And in fact, the baby’s brain seems be the most powerful learning computer on the planet. But computers are actually getting to be a lot better. And there’s been a revolution in our understanding machine learning recently. And it all depends on the of this guy, the Reverend Thomas Bayes, who was statistician and mathematician in the 18th century. And essentially what Bayes did to provide a mathematical way using probability theory to characterize, describe, way that scientists find out about the world. So what scientists do is they a hypothesis that they think might be likely to start with. They go and test it against the evidence. The evidence makes change that hypothesis. Then they test that new hypothesis so on and so forth. And what Bayes showed a mathematical way that you could do that. And that mathematics is at the core of best machine learning programs that we have now. And 10 years ago, I suggested that babies might be doing the same thing.
So if you 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 actually making complicated calculations with conditional probabilities that they’re revising to figure out how world works. All right, now that might seem like an even taller to actually demonstrate. Because after all, if you ask even about statistics, they look extremely stupid. How could it be that children doing statistics?
So to test this we used a that we have called the Blicket Detector. This is a that lights up and plays music when you put some things on it and others. And using this very simple machine, my lab and others done dozens of studies showing just how good babies at learning about the world. Let me mention just one we did with Tumar Kushner, my student. If I showed you this detector, you be likely to think to begin with that the to make the detector go would be to put a block on top of detector. But actually, this detector works in a bit of strange way. Because if you wave a block over the of the detector, something you wouldn’t ever think of begin with, the detector will actually activate two out three times. Whereas, if you do the likely thing, the block on the detector, it will only activate two out of times. So the unlikely hypothesis actually has stronger evidence. looks as if the waving is a more effective strategy than the other strategy. we did just this; we gave four year-olds this pattern of evidence, and we asked them to make it go. And sure enough, the four year-olds used evidence to 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 learning how to count. But unconsciously, they’re doing these quite complicated calculations that 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 the world, that seems very unlikely 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 when we give them exactly the same task. So these circumstances, the children are using statistics to find out about the world, after all, scientists also do experiments, and we wanted to see if children doing experiments. When children do experiments we call it “getting everything” or else “playing.”
And there’s been a bunch of interesting studies that have shown this playing around is really a kind of experimental research program. Here’s one Cristine Legare’s lab. What Cristine did was use our Blicket Detectors. And what she did show 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 boy will go through five hypotheses in the space two minutes.
(Video) Boy: How about this? Same as the side.
Alison Gopnik: Okay, so his first hypothesis has just been falsified.
(Laughter)
Boy: This one up, and this one nothing.
AG: Okay, he’s got his experimental notebook out.
Boy: What’s making light up. (Laughter) I don’t know.
AG: Every scientist recognize that expression of despair.
(Laughter)
Boy: Oh, it’s because needs to be like this, and this needs to be 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 putting it 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 hypothesis.
Boy: It’s lighting up. So when you put four. So you put on this one to make it light up and two on this one to make light up.
AG: Okay,there’s his fifth hypothesis.
Now that a particularly — that is a particularly adorable and articulate little boy, but Cristine discovered is this is actually quite typical. If look at the way children play, when you ask to explain something, what they really do is do a of experiments. This is actually pretty typical of four year-olds.
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Well, what’s it like to 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, a lot of have said that babies and young children were barely conscious if they conscious at all. And I think just the opposite true. I think babies and children are actually more conscious than we as adults. Now here’s what we know about how consciousness works. And adults’ attention and consciousness look kind of a spotlight. So what happens for adults is we decide that something’s relevant or important, we should attention to it. Our consciousness of that thing that we’re attending to extremely bright and vivid, and everything else sort of goes dark. And we even know something about 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 a part of our brain much more flexible, more plastic, better at learning, and down activity in all the rest of our brains. So we have very focused, purpose-driven kind of attention. If we look at babies and young children, we something very different. I think babies and young children seem to more of a lantern of consciousness than a spotlight of consciousness. So babies and young children very bad at narrowing down to just one thing. But they’re very good at taking lots of information from lots of different sources at once. And if actually look in their brains, you see that they’re flooded with these neurotransmitters that really good at inducing learning and plasticity, and the inhibitory haven’t come on yet. So when we say that babies and children are bad at paying attention, what we really mean that they’re bad at 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 kind consciousness, that we might expect from those butterflies who are to learn.
Well if we want to think about a of getting a taste of that kind of baby as adults, I think the best thing is think cases where 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 in new city for the first time. And what happens then is not that consciousness contracts, it expands, so that those three days Paris seem to be more full of consciousness and than all the months of being a walking, talking, faculty meeting-attending zombie back home. And by way, that coffee, that wonderful coffee you’ve been drinking downstairs, actually mimics the effect of baby neurotransmitters. So what’s it like to be a baby? It’s like being in love in Paris for the time after you’ve had three double-espressos. (Laughter) That’s a fantastic way to be, but it does to leave you waking up crying at three o’clock in the morning.
(Laughter)
Now it’s to be a grownup. I don’t want to say too much how wonderful babies are. It’s good to be a grownup. can do things like tie our shoelaces and cross street by ourselves. And it makes sense that we a lot of effort into making babies think like adults do. But if what we want to be like those butterflies, to have open-mindedness, open learning, imagination, creativity, innovation, maybe least some of the time we should be getting the adults start thinking more like children.
(Applause)