What is going on in this baby’s mind? you’d asked people this 30 years ago, most people, including psychologists, would have said that baby was irrational, illogical, egocentric — that he couldn’t take perspective of another person or understand cause and effect. In the last 20 years, science has completely overturned that picture. So in some ways, think that this baby’s thinking is like the thinking the most brilliant scientists.
Let me give you just one example of this. One that this baby could be thinking about, that could be going on in his mind, is to figure out what’s going on in the mind of that other baby. all, one of the things that’s hardest for all of us to do to figure out what other people are thinking and feeling. And maybe the hardest 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 some people to get. We wanted to know 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 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 — actually to give the babies two bowls of food: one bowl of raw and one bowl of delicious goldfish crackers. Now all of the babies, even Berkley, like the crackers and don’t like the raw broccoli. (Laughter) then what Betty did was to take a little taste food 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 — like a 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 the broccoli. Mmmmm.” then she would take a 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 what the babies wanted. We did this with 15 and 18 month-old babies. And she would simply put her hand out and say, “Can you give some?”
So the question is: What would the baby 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. the other hand, 15 month-olds would stare at her a long time if she acted as if she liked broccoli, like they couldn’t figure this out. But then they stared for a long time, they would just her the crackers, what they thought everybody must like. So there are two remarkable things about this. The first one is that these 18 month-old babies have already discovered this really profound fact human nature, that we don’t always want the same thing. And what’s more, they felt they should actually do things to help other people get what they wanted.
Even more though, the fact that 15 month-olds didn’t do this that these 18 month-olds had learned this deep, profound about human nature in the three months from when they 15 months old. So children both know more and learn than we ever would have thought. And this is just one of and hundreds of studies over the last 20 years that’s actually it.
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The question you might ask though is: Why children learn so much? And how is it possible for them learn so much in such a short time? I mean, after all, you look at babies superficially, they seem pretty useless. actually in many ways, they’re worse than useless, because have to put so much time and energy into keeping them alive. But if we turn to evolution for answer to this puzzle of why we spend so much time taking care of useless babies, it turns that there’s actually an answer. If we look across many, many different species of animals, not us primates, but also including other mammals, birds, even like kangaroos and wombats, it turns out that there’s a relationship between how a childhood a species has and how big their brains compared to their bodies and 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 other corvidae, ravens, and so forth, are incredibly smart birds. They’re as as chimpanzees in 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 the domestic chicken. And chickens and ducks and geese and turkeys are basically dumb as dumps. So they’re very, very good at for grain, and they’re not much good at doing anything else. Well it out that the babies, the New Caledonian crow babies, are fledglings. depend on their moms to drop worms in their little open for as long as two 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 kind explanation could we have for this? Well some animals, like the chicken, seem to be beautifully suited to 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 at doing anything in particular, but they’re extremely good at learning about of different environments.
And of course, we human beings way out on the end of the distribution like the crows. We have bigger brains relative to our by far than any other animal. We’re smarter, we’re more flexible, can learn more, we survive in more different environments, we migrated cover the world and even go to outer space. our babies and children are dependent on us for longer than the babies of any other species. My son is 23. (Laughter) And at until they’re 23, we’re still popping those worms into those open mouths.
All right, why would we see this correlation? Well an idea is that strategy, that learning strategy, is an extremely powerful, 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 you don’t want have the mastodon charging at you and be saying to yourself, “A slingshot or maybe spear might work. Which would actually be better?” You want know all that before the mastodons actually show up. the way the evolutions seems to have solved that problem is with kind of division of labor. So the idea is we have this early period when we’re completely protected. We don’t have to do anything. All we to do is learn. And then as adults, we take all those things that we learned when we were babies and children actually put them to work to do things out in the world.
So one way of thinking about it that babies and young children are like the research development division of the human species. So they’re the protected blue sky guys just have to go out and learn and have ideas, and we’re production and marketing. We have to take those ideas that we learned when we were children and actually put them use. Another way of thinking about it is instead of of babies and children as being like defective grownups, we should think about as being a different developmental stage of the same species — kind of like caterpillars and butterflies — that they’re actually the brilliant butterflies who are flitting around the and exploring, and we’re the caterpillars who are inching along narrow, grownup, adult path.
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If this is true, if these babies are designed to — and this evolutionary story would say children are learning, that’s what they’re for — we might expect that they would have powerful learning mechanisms. And in fact, the baby’s brain to be the most powerful learning computer on the planet. But real computers are actually to be a lot better. And there’s been a revolution in our understanding of machine recently. And it all depends on the ideas of guy, the Reverend Thomas Bayes, who was a statistician mathematician in the 18th century. And essentially what Bayes was to provide a mathematical way using probability theory characterize, describe, the way that scientists find out about world. So what scientists do is they have a that they think might be likely to start with. They go out test it against the evidence. The evidence makes them change that hypothesis. Then they that new hypothesis and so on and so forth. And what Bayes showed was a mathematical that you could do that. And that mathematics is the core of the best machine learning programs that have now. And some 10 years ago, I suggested that babies might be the same thing.
So if you want to know what’s going on underneath those beautiful brown eyes, think it actually looks something like this. This is Reverend Bayes’s notebook. I think those babies are actually making complicated calculations with conditional probabilities that they’re revising figure out how the world works. All right, now that seem like an even taller order to actually demonstrate. Because after all, if ask even grownups about statistics, they look extremely stupid. could it be that children are doing statistics?
So to test this used a machine that we have called the Blicket Detector. is a box that lights up and plays music you put some things on it and not others. using this very simple machine, my lab and others have done dozens of studies showing how good babies are at learning about the world. Let me mention just one that we with Tumar Kushner, my student. If I showed you this detector, would be likely to think to begin with that the way to the detector go would be to put a block on top of the detector. But actually, this works in a bit of a strange way. Because if you a block over the top of the detector, something you wouldn’t ever of to begin with, the detector will actually activate two out of three times. Whereas, if do the likely thing, put the block on the detector, it only activate two out of six times. So the unlikely hypothesis actually has evidence. It looks as if the waving is a 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 enough, the four year-olds used the evidence to wave the object on top the detector.
Now there are two things that are really interesting about this. The first is, again, remember, these are four year-olds. They’re just learning how to count. unconsciously, they’re doing these quite complicated calculations that will them a conditional probability measure. And the other interesting thing is that they’re using that 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 actually better at finding out an unlikely hypothesis than are when we give them exactly the same task. So in circumstances, the children are using statistics to find out about the world, after all, scientists also do experiments, and we wanted to if children are doing experiments. When children do experiments call it “getting into everything” or else “playing.”
And there’s a bunch of interesting studies recently that have shown this playing is really a kind of experimental research program. Here’s one Cristine Legare’s lab. What Cristine did was use our Blicket Detectors. what 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 see is that this little boy go through five hypotheses in the space of two minutes.
(Video) Boy: How about this? as the other side.
Alison Gopnik: Okay, so his first 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 up. (Laughter) I don’t know.
AG: Every scientist will 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 his next idea. told the experimenter to do this, to try putting it out onto other location. Not working either.
Boy: Oh, because the light goes 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 put four. you put four on this one to make it light up and on this one to make it light up.
AG: Okay,there’s his hypothesis.
Now that is a particularly — that is a particularly adorable and articulate boy, but what Cristine discovered is this is actually quite typical. you look at the way children play, when you ask to explain something, what they really do is do a series experiments. This 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 hypotheses in two minutes? Well, if you go back to those psychologists philosophers, a lot of them have said that babies and young children were conscious if they were conscious at all. And I think just the opposite is true. I think and children are actually more conscious than we are adults. Now here’s what we know about how adult works. And adults’ attention and consciousness look kind of like a spotlight. So what happens for is we decide that something’s relevant or important, we should pay attention to it. Our consciousness of that that we’re attending to becomes extremely bright and vivid, and everything else sort of dark. And 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, a signal that makes a little part of our brain much more flexible, plastic, better at learning, and shuts down activity in the rest of our brains. So we have a focused, purpose-driven kind of attention. If we look at babies and children, we see something very different. I think babies young children seem to have more of a lantern of consciousness than a of consciousness. So babies and young children are very at narrowing down to just one thing. But they’re good at taking in lots of information from lots of different sources at once. And if you look in their brains, you see that they’re flooded with these that are really good at inducing learning and plasticity, and the parts haven’t come on yet. So when we say that babies young children are bad at paying attention, what we really mean is that they’re at not paying attention. So they’re bad at getting rid of all the interesting things could tell them something and just looking at the thing that’s important. That’s kind of attention, the kind of consciousness, that we might from those butterflies who are designed to learn.
Well we want to think about a way of getting taste of that kind of baby consciousness as adults, I think the best thing is think about cases we’re put in a new situation that we’ve never been in before — when we in love 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 days in Paris seem to be more full of consciousness and than all the months of being a walking, talking, faculty meeting-attending back home. And by the way, that coffee, that wonderful coffee you’ve been downstairs, actually mimics the effect of those baby neurotransmitters. So what’s it to be a baby? It’s like being in love 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 crying at three o’clock in the morning.
(Laughter)
Now it’s good to be grownup. I don’t want to say too much about how wonderful are. It’s good to be a grownup. We can things like tie 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 if what we is to be like those butterflies, to have open-mindedness, open learning, imagination, creativity, innovation, at least some of the time we should be getting the adults start thinking more like children.
(Applause)