What is going on this baby’s mind? If you’d asked people this 30 years ago, people, including psychologists, would have said that this baby was irrational, illogical, — that he couldn’t take the perspective of another person or cause and effect. In the last 20 years, developmental science has completely 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 of this. thing that this baby could be thinking about, that could going on in his mind, is trying to figure what’s going on in the mind of that other baby. all, one of the things that’s hardest for all of to do is to figure out what other people are thinking and feeling. And maybe 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 followed politics testify to how hard that is for some people to get. We wanted to know if and young children could understand this really profound thing about other people. Now the question is: How could ask 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 stream 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 — 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 Berkley, like the crackers and don’t like the raw broccoli. (Laughter) But then what Betty did was take a little taste of food from each bowl. And 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 — just like a baby and any other sane person. But the time, what she would do is take a 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 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? the remarkable thing was that 18 month-old babies, just barely walking and talking, give her the crackers if she liked the crackers, they would give her the broccoli if she liked broccoli. On the 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 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 this profound fact about human nature, that we don’t always want same thing. And what’s more, they felt that they should actually do things to help other people get they wanted.
Even more remarkably though, the fact that 15 month-olds didn’t do this suggests that 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 thought. And this is just one of hundreds and hundreds studies over the last 20 years that’s actually demonstrated it.
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The question might ask though is: Why do children learn so much? And how is it possible for them learn so much in such a short time? I mean, after all, if you look at superficially, they seem pretty useless. And actually in many ways, they’re than useless, because we have to put so much time and into just keeping them alive. But if we turn to evolution for an answer to this puzzle why we spend so much time taking care of useless babies, it turns out there’s actually an 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, it out that there’s a relationship between how long a childhood a has and how big their brains are compared to their and how smart and flexible they are.
And sort of posterbirds for this idea are the birds up there. On one is a New Caledonian crow. And crows and other corvidae, ravens, and so forth, are incredibly smart birds. They’re as smart as chimpanzees in some respects. And this is bird on the cover of science who’s learned how to use a tool to 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, good at pecking for grain, and they’re not much good at doing anything else. Well it out that the babies, the New Caledonian crow babies, fledglings. They depend on their moms to drop worms in their little open mouths for as long as years, which is a really long time in the of a bird. Whereas the chickens are actually mature within couple of months. So childhood is the reason why the crows end up on the of 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 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 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 about laws of environments.
And of course, we human beings are way on the end of the distribution like the crows. have bigger brains relative to our bodies by far than any animal. We’re smarter, we’re more flexible, we can learn more, we in more different environments, we migrated to cover the world and even go to outer space. our babies and children are dependent on us for much longer than the babies of any other species. son is 23. (Laughter) And at least until they’re 23, we’re still those worms into those little open mouths.
All right, why 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 slingshot or a spear might work. Which would actually be better?” You want to know all that before the actually show up. And the way the evolutions seems to have solved that problem with a kind of division of labor. So the idea is 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 all those things we learned when we were babies and children and actually them to work to do things out there in world.
So one way of thinking about it is that babies and young children are like research and development division of the human species. So they’re the protected blue sky guys just have to go out and learn and have good ideas, and we’re and marketing. We have to take all those ideas that we learned when were children and actually put them to use. Another way of thinking about it is of thinking of babies and children as being like 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 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 is true, if these babies are designed to learn — and this evolutionary story would say 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 computer on the planet. But computers are actually getting to be a lot better. And there’s a revolution in our understanding of machine learning recently. it all depends on the ideas of this guy, the Reverend Thomas Bayes, was a statistician and mathematician in the 18th century. essentially what Bayes did was to provide a mathematical way using 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 and it against the evidence. The evidence makes them change hypothesis. Then they test that new hypothesis and so on and forth. And what Bayes showed was a mathematical way you could do that. And that mathematics is at core of the best machine learning programs that we now. And some 10 years ago, I suggested that might be doing the same thing.
So if you to know 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 babies are actually making complicated calculations conditional probabilities that they’re revising to figure out how the world works. All right, now might seem like an even taller order to actually demonstrate. after all, if you ask even grownups about statistics, they look extremely stupid. How could it be that are doing statistics?
So to test this we used a machine that we called the Blicket Detector. This is a box that lights up and plays music when put some things on it and not others. And using this very simple machine, my lab and have done dozens of studies showing just how good babies are learning about the world. Let me mention just one that we did Tumar Kushner, my student. If I showed you this detector, would be likely to think to begin with that way to make the detector go would be to a block on top of the detector. But actually, this detector in a bit of a strange way. Because if you a block over the top of the detector, something wouldn’t ever think of to begin with, the detector will activate two out of three times. Whereas, if you do likely thing, put the block on the detector, it will only activate two of six times. So the unlikely hypothesis actually has stronger evidence. looks as if the waving is a more effective strategy than other strategy. So we did just this; we gave four year-olds this pattern evidence, and we just 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 are two things are really interesting 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 give them a conditional probability measure. And the other interesting is that they’re using that evidence to get to an idea, get to hypothesis about the world, that seems very unlikely to with. And in studies we’ve just been doing in lab, similar studies, we’ve show that four year-olds are actually better at finding out an unlikely hypothesis than are when we give them exactly the same task. in these circumstances, the children are using statistics to out about the world, but after all, scientists also experiments, and we wanted to see if children are doing experiments. When do experiments we call it “getting into everything” or “playing.”
And there’s been a bunch of interesting studies recently have shown this playing around is really a kind experimental research program. Here’s one from Cristine Legare’s lab. What Cristine did use our Blicket Detectors. And what she did was show children that yellow ones made go and red ones didn’t, and then she showed an anomaly. And what you’ll see is that this little 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 hypothesis has just been falsified.
(Laughter)
Boy: This one lighted up, and this nothing.
AG: Okay, he’s got his experimental notebook out.
Boy: What’s making this light up. (Laughter) don’t know.
AG: Every scientist will recognize that expression of despair.
(Laughter)
Boy: Oh, it’s because needs to be like this, and this needs to like this.
AG: Okay, hypothesis two.
Boy: That’s why. Oh.
(Laughter)
AG: Now this his next idea. He told the experimenter to do this, to try it out onto the other location. Not working either.
Boy: Oh, the light goes only to here, not here. Oh, bottom of this box has electricity in here, but this doesn’t electricity.
AG: Okay, that’s a fourth hypothesis.
Boy: It’s up. So when you put four. So you put 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 that a particularly — that is a particularly adorable and articulate little boy, but Cristine discovered is this is actually quite typical. If you at the way children play, when you ask them explain something, what they really do is do a series of experiments. is actually pretty typical of four year-olds.
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Well, what’s it like to be this kind of creature? What’s like to be one 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 if they were conscious at all. And I think just the opposite is true. I babies and children are actually more conscious than we are as adults. Now here’s what know about how adult consciousness works. And adults’ attention and consciousness kind of like a spotlight. So what happens for adults is we decide that something’s relevant or important, should 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 does this.
So what happens when we attention is that the prefrontal cortex, the sort of executive part of our brains, sends a signal makes a little part of our brain much more flexible, plastic, better at learning, and shuts down activity in all the of our brains. So we have a very focused, purpose-driven of attention. If we look at babies and young children, we see something very different. I think babies and children seem to have more of a lantern of 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 taking lots of information from lots of different sources at once. if you actually look in their brains, you see that they’re with these neurotransmitters that are 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 is that they’re bad at not paying attention. they’re bad at getting rid of all the interesting things that tell them something and just looking at the thing that’s important. That’s the kind attention, the kind of consciousness, that we might expect from those who are designed to learn.
Well if we want think about a way of getting a taste of that kind of baby as adults, I think the best thing is think about cases where we’re put a new situation that we’ve never been in before — when we fall in love with someone new, or we’re in a new city for the first time. And what happens then is not our consciousness contracts, it expands, so that those three days Paris seem to be more full of consciousness and experience than all the months of a walking, talking, faculty meeting-attending zombie back home. And the way, that coffee, that wonderful coffee you’ve been drinking downstairs, actually mimics the of those baby neurotransmitters. So what’s it like to be a baby? It’s being in love in Paris for the first time after you’ve three double-espressos. (Laughter) That’s a fantastic way to be, but it does tend to leave you waking crying at three o’clock in the morning.
(Laughter)
Now it’s good to be a grownup. I don’t want to too much about how wonderful babies are. It’s good be a grownup. We can do things like tie our shoelaces and cross the street ourselves. And it makes sense that we put a lot of effort 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 adults to start thinking more like children.
(Applause)