What is on in this baby’s mind? If you’d asked people 30 years ago, most people, including psychologists, would have that this baby was irrational, illogical, egocentric — that he couldn’t take the perspective of another person or cause and effect. In the last 20 years, developmental science has completely overturned picture. So in some ways, we think that this baby’s thinking is like thinking of the most brilliant scientists.
Let me give you just one example of this. One thing that baby could be thinking about, that could be going on in mind, is trying to figure out what’s going on in the mind of other baby. After all, one of the things that’s hardest all of us to do is to figure out other people are thinking and feeling. And maybe the hardest of all is to figure out that what other people think and feel isn’t actually exactly like we think and feel. Anyone who’s followed politics can testify how hard that is for some people to get. We to know if babies and young children could understand this profound thing about other people. Now the question is: How we ask them? Babies, after all, can’t talk, and if you a three year-old to tell you what he thinks, what you’ll is a beautiful stream of consciousness monologue about ponies birthdays and things like that. So how do we actually them the question?
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Well it turns out that the was broccoli. What we did — Betty Rapacholi, who one of my students, and I — was actually to the babies two bowls of food: one bowl of raw broccoli and one 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 of food from each bowl. And she would act as if she liked it she didn’t. So half the time, she acted as if liked the crackers and didn’t like the broccoli — like a baby and any other sane person. But the time, what she would do is take a little of the broccoli and go, “Mmmmm, broccoli. I tasted broccoli. Mmmmm.” And then she would take a little 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 the opposite of what the babies wanted. We did this 15 and 18 month-old babies. And then she would simply put her out and say, “Can you give me some?”
So the question is: What would the give her, what they liked or what she liked? And remarkable thing was that 18 month-old babies, just barely walking and talking, would give her the if she liked the crackers, but they would give her the broccoli if liked the broccoli. On the other hand, 15 month-olds would at her for a long time if she acted as if liked the broccoli, like they couldn’t figure this out. then after they stared for a long time, they would just give the crackers, what they thought everybody must like. So are two really remarkable things about this. The first one is these little 18 month-old babies have already discovered this really fact about human nature, that we don’t always want same thing. And what’s more, they felt that they should actually things to help other people get what they wanted.
Even remarkably though, the fact that 15 month-olds didn’t do this suggests that these 18 month-olds had learned deep, profound fact about human nature in the three months when they were 15 months old. So children both know and learn more than we ever would have thought. And is just one of hundreds and hundreds of studies over last 20 years that’s actually 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 so much in such a short time? I mean, after all, if you at babies superficially, they seem pretty useless. And actually in ways, they’re worse than useless, because we have to put so much time and into just keeping them alive. But if we turn evolution for an answer to this puzzle of why we spend so much time taking of useless babies, it turns out that there’s actually an answer. If we look across many, different species of animals, not just us primates, but also including other mammals, birds, even marsupials like and wombats, it turns out that there’s a relationship between how long childhood a species has and how big their brains are compared to their bodies how smart and flexible they are.
And sort of the posterbirds for this are the birds up there. On one side is a New Caledonian crow. And and other corvidae, ravens, rooks and so forth, are incredibly smart birds. They’re smart as chimpanzees in some respects. And this is a bird the cover of science who’s learned how to use a tool get food. On the other hand, we have our the domestic chicken. And chickens and ducks and geese turkeys 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 crow babies, are fledglings. They depend on their moms to drop worms their little open mouths for as long as two years, which is a really long time in life of a bird. Whereas the chickens are actually within a couple of months. So childhood is the reason the crows end up on the cover of Science and the end up in the soup pot.
There’s something about that long childhood that seems to be to knowledge and learning. Well what kind of explanation could we for this? Well some animals, like the chicken, seem to beautifully suited to doing just one thing very well. they seem to be beautifully suited to pecking grain in environment. Other creatures, like the crows, aren’t very good at doing anything particular, but they’re extremely good at learning about laws of environments.
And of course, we human beings are way out on the end of the distribution the crows. We have bigger brains relative to our by far than any other animal. We’re smarter, we’re flexible, we can learn more, we survive in more different environments, we to cover the world and even go to outer space. And our babies and children are 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, an extremely powerful, great strategy for getting on in the world, it has one big disadvantage. And that one big disadvantage is that, until you actually all that learning, you’re going to be helpless. So don’t want to have the mastodon charging at you be saying to yourself, “A slingshot or maybe a might work. Which would actually be better?” You want to know all that the mastodons actually show up. And the way the evolutions seems to have solved that problem is a kind of division of labor. So the idea is that we have this period when we’re completely protected. We don’t have to do anything. we have to do is learn. And then as adults, we can take all those things that we when we were babies and children and actually put to work to do things out there in the world.
So one of thinking about it is that babies and young are like the research and development division of the human species. So they’re the protected blue guys who just have to go out and learn and have ideas, and we’re production and marketing. We have to all those ideas that we learned when we were children and actually put them use. Another way of thinking about it is instead of thinking of babies and as being like defective grownups, we should think about them as a different developmental stage of the same species — kind like caterpillars and butterflies — except that they’re actually the brilliant butterflies who are flitting the garden and exploring, and we’re the caterpillars who are inching along our narrow, grownup, path.
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If this is true, if these babies are to learn — and this evolutionary story would say children are learning, that’s what they’re for — we might expect they would have really powerful learning mechanisms. And in fact, the baby’s seems to 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 our understanding of machine learning recently. And it all depends on ideas of this guy, the Reverend Thomas Bayes, who was statistician and mathematician in the 18th century. And essentially what did 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 hypothesis they think might be likely to start with. They go out and test against the evidence. The evidence makes them change that hypothesis. they test that new hypothesis and so on and forth. And what Bayes showed was a mathematical way that you could do that. And mathematics is at the 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 want to know what’s going underneath those beautiful brown eyes, I think it actually looks like this. This is Reverend Bayes’s notebook. So I think those babies are making complicated calculations with conditional probabilities that they’re revising to figure out how the world works. All right, that might seem like an even taller order to actually demonstrate. Because after all, if you even grownups about statistics, they look extremely stupid. How it be that children are doing statistics?
So to test this we used a machine that we called the Blicket Detector. This is a box that up and plays music when you put some things it and not others. And using this very simple machine, my lab and others have dozens of studies showing just how good babies are learning about the world. Let me mention just one that did with Tumar Kushner, my student. If I showed this detector, you would be likely to think to with that the way to make the detector go would be to put a block on of the 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 of times. Whereas, if you do the likely thing, put block on the detector, it will only activate two out six times. So the unlikely hypothesis actually has stronger evidence. It looks if the waving is a more effective strategy than the other strategy. So did just this; we gave four year-olds this pattern of evidence, and we just asked to make it go. And sure enough, the four year-olds used the evidence to wave the on top of the detector.
Now there are two things that are really about this. The first one is, again, remember, these are four year-olds. They’re learning how to count. But unconsciously, they’re doing these quite complicated calculations will give them a conditional probability measure. And the interesting thing is that they’re using that evidence to get to an idea, get a hypothesis about the world, that seems very unlikely to begin with. And in studies we’ve been doing in my lab, similar studies, we’ve show four year-olds are actually better at finding out an unlikely than adults are when we give them exactly the same task. So in circumstances, the children are using statistics to find out about the world, but all, scientists also do experiments, and we wanted to see if children are doing experiments. When children do we call it “getting into 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. what she 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 see is that this little will go through five hypotheses in the space of two minutes.
(Video) Boy: How about this? Same 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 notebook out.
Boy: What’s this light up. (Laughter) I don’t know.
AG: Every will recognize that expression of despair.
(Laughter)
Boy: Oh, it’s this needs to be like this, and this needs be like this.
AG: Okay, hypothesis two.
Boy: That’s why. Oh.
(Laughter)
AG: Now this is next idea. He told the experimenter to do this, to try it out onto the other location. Not working either.
Boy: Oh, because the goes only to here, not here. Oh, the bottom of this box has electricity 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 four on this one to make it light up and two on one to make it light up.
AG: Okay,there’s his hypothesis.
Now that is a particularly — that is a particularly adorable articulate little boy, but what Cristine discovered is this is actually quite typical. If you look at the children play, when you ask them to explain something, they really do is do a series of experiments. This is actually typical of four year-olds.
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Well, what’s it to be this kind of creature? What’s it like to be one of these brilliant butterflies can test five hypotheses in two minutes? Well, if go back to those psychologists and philosophers, a lot of have said that babies and young children were barely conscious if they were 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 we about how adult consciousness works. And adults’ attention and consciousness kind of like a spotlight. So what happens for adults we decide that something’s relevant or important, we should pay to it. Our consciousness of that thing that we’re attending to becomes extremely bright and vivid, and else sort of goes dark. And we even know something about the the brain does this.
So what happens when we attention is that the prefrontal cortex, the sort of executive 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 and young children, we see something very different. I babies and young children seem to have more of a lantern consciousness than a spotlight of consciousness. So babies and young children are bad at narrowing down to just one thing. But they’re very at taking in lots of information from lots of different at once. And if you actually look in their brains, you that they’re flooded with these neurotransmitters that are really good at inducing learning and plasticity, and the parts haven’t come on yet. So when we say that babies and young children are bad at attention, what we really mean is that they’re bad not paying attention. So they’re bad at getting rid of all interesting things that could 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 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 where we’re put in a situation that we’ve never been in before — when we fall in love with new, or when we’re in a new city for the first time. And what happens then is that our consciousness contracts, it expands, so that those three days Paris seem to be more full of consciousness and experience 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 those neurotransmitters. So what’s it like to be a baby? It’s being in love in Paris for the first time 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 good be a grownup. I don’t want to say too much about how wonderful babies are. It’s good be a grownup. We can do things like tie our and cross the street by ourselves. And it makes sense that we put a 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 at some of the time we should be getting the adults to start thinking more children.
(Applause)