What is going in 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 another person or understand cause and effect. In the last 20 years, developmental has completely overturned that picture. So in some ways, we think this baby’s thinking is like the thinking of the most brilliant scientists.
Let me you just one example of this. One thing that this baby could be about, that could be 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. maybe the hardest thing of all is to figure out that other people think and feel isn’t actually exactly like what we and feel. Anyone who’s followed politics can testify to how hard that for some people to get. We wanted to know if babies and young children could understand this profound thing about other 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 you he thinks, what you’ll get is a beautiful stream consciousness monologue about ponies and birthdays and things like that. So how do we actually ask them question?
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Well it turns out that the secret was broccoli. What did — Betty Rapacholi, who was one of my students, and I — was to give the babies two bowls of food: one of raw broccoli and one bowl of delicious goldfish crackers. Now all of the babies, in Berkley, like the crackers and don’t like the broccoli. (Laughter) But then what Betty did was to take little taste 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 she liked the and didn’t like the broccoli — just like a and any other sane person. But half 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. tasted the crackers. Eww, yuck.” So she’d act as if what she was just the opposite of what the babies wanted. We did with 15 and 18 month-old babies. And then she would simply put her hand out say, “Can you give me some?”
So the question is: What would the baby give her, what liked or what she liked? And the remarkable thing was that 18 month-old babies, just walking and talking, would give her the crackers if liked the crackers, but they would give her the if she liked the broccoli. On 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 after stared for a long time, they would just give her the crackers, what they thought everybody must like. there are two really remarkable things about this. The one is that these little 18 month-old babies have already discovered this really profound fact about human nature, we don’t always want the same thing. And what’s more, they felt that 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 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 children both know more learn more than we ever would have thought. And this is just of hundreds and hundreds of studies over the last 20 years that’s demonstrated it.
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The question you might ask though is: Why do learn so much? And how is it possible for to learn so much in such a short time? I mean, after all, you look at babies superficially, they seem pretty useless. And in many ways, they’re worse than useless, because we have to so much time and energy into just keeping them alive. if we turn to evolution for an answer to this puzzle why we spend so much time taking care of babies, it turns out that there’s actually an answer. we look across many, many different species of animals, not just us primates, also including other mammals, birds, even marsupials like kangaroos and wombats, it turns out there’s a relationship between how long a childhood a species and how big their brains are compared to their and how smart and flexible they are.
And sort of the posterbirds for this idea are birds up there. On one side is a New crow. And crows 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 on the cover 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 and geese and turkeys are basically as dumb as dumps. So they’re very, very good at pecking for grain, they’re not much good at doing anything else. Well it turns out the babies, the New Caledonian crow babies, are fledglings. They depend on their moms to drop worms in little open mouths for 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 the reason why the crows end up on the of Science and the chickens end up in the pot.
There’s something about that long childhood that seems to be connected to and learning. Well what kind of explanation could we have for this? Well some animals, like chicken, seem to be beautifully suited to doing just one thing very well. So seem to be beautifully suited to pecking grain in environment. Other creatures, like the crows, aren’t very good doing anything in particular, but they’re extremely good at learning laws of different environments.
And of course, we human are way out on the end of the distribution the crows. We have bigger brains relative to our bodies by than any other animal. We’re smarter, we’re more flexible, we can learn more, survive in more different environments, we migrated to cover the world and even go to space. And our babies and children are dependent on us 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 worms those little open mouths.
All right, why would we this correlation? Well an idea is that that strategy, learning strategy, is an extremely powerful, great strategy for getting on in the world, but it has one disadvantage. And that one big disadvantage is that, until you actually do all that learning, you’re going be helpless. So you don’t want to have the charging at you and be saying to yourself, “A slingshot or a spear might work. Which would actually be better?” You to know all that before the mastodons actually show up. And the way the seems to have solved that problem is 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 put them to work to do things there in the world.
So one way of thinking about is that babies and young children are like the and development division of the human species. So they’re the protected blue sky who 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 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 that they would have really powerful learning mechanisms. And fact, the baby’s brain seems to be the most powerful learning computer on planet. But real computers are actually getting to be lot better. And there’s been a revolution in our understanding of learning recently. And it all depends on the ideas of guy, the Reverend Thomas Bayes, who was a statistician and in the 18th century. And essentially what Bayes did was to provide mathematical way using probability theory to characterize, describe, the way that find out about the world. So what scientists do is they have a hypothesis they think might be likely to start with. They out and test it against the evidence. The evidence makes them change that hypothesis. they test that new hypothesis and so on and so forth. And what showed was a mathematical way that you could do that. And that is at the core of the best machine learning that we have now. And some 10 years ago, I suggested babies might be doing the same thing.
So if you want to know what’s going on underneath those brown 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 to figure out how the works. All right, now that might seem like an even taller order to actually demonstrate. Because after all, 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 that we have called the Blicket Detector. This is box that lights up and plays music when you some things on it and not others. And using this very simple machine, my lab others have done dozens of studies showing just how good babies are at about the world. Let me mention just one that we did with Tumar Kushner, my student. If 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 on top the detector. But actually, this detector works in a bit a strange way. Because if you wave a block the top of the detector, something you wouldn’t ever think of to begin with, the detector will activate two out of three times. Whereas, if you the likely thing, put the block on the detector, it will activate two out 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 of evidence, and we just asked them to make it go. And sure enough, four year-olds used the evidence to wave the object on of the detector.
Now there are two things that really interesting about this. The first one is, again, remember, these four year-olds. They’re just learning how to count. But unconsciously, they’re doing these quite complicated calculations that will give a conditional probability measure. And the other interesting thing that they’re using that evidence to get to an idea, get to a hypothesis about the world, that seems unlikely to begin 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 hypothesis than adults are when we give them exactly same task. So in these circumstances, the children are statistics to find out about the world, but after all, scientists do experiments, and we wanted to see if children are 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 experimental research program. Here’s one from Cristine Legare’s lab. What did was use our Blicket Detectors. And what she did was show children that yellow ones it go and red ones didn’t, and then she showed them an anomaly. And what you’ll see that this little boy will go through five hypotheses the space of two minutes.
(Video) Boy: How about this? Same as the other side.
Alison Gopnik: Okay, so first hypothesis has just been falsified.
(Laughter)
Boy: This one lighted up, and one 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 to like this, and this needs to be like 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 putting it out onto the other location. Not working either.
Boy: Oh, because light goes only to here, not here. Oh, the bottom of this box has 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 light up and two on this one to make light up.
AG: Okay,there’s his fifth hypothesis.
Now that is a — 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 them to explain something, what they really do is a series of experiments. This is actually pretty typical four year-olds.
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Well, what’s it like to be kind of creature? What’s it like to be one of these brilliant butterflies can test five hypotheses in two minutes? Well, if you go back those psychologists and philosophers, a lot of them have said that babies and young children were barely 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 as adults. here’s what we know about how adult consciousness works. And adults’ attention and consciousness look of like a spotlight. So what happens for adults is we that something’s relevant or important, we should pay attention it. Our consciousness of that thing that we’re attending to becomes extremely bright and vivid, and everything else of goes dark. And we even know something about the the brain does this.
So what happens when we pay is that the prefrontal cortex, the sort of executive part our brains, sends a signal that makes a little part of our brain much more flexible, plastic, better at learning, and shuts down activity in all rest of our brains. So we have a very focused, purpose-driven of attention. If we look at babies and young children, we something very different. I think babies and young children seem to have more of a lantern consciousness than a spotlight of consciousness. So babies and young children are very bad at narrowing down to one thing. But they’re very good at taking in lots of information lots of different sources at once. And if you actually look in their brains, you see they’re flooded with these neurotransmitters that are really good inducing learning and plasticity, and the inhibitory parts haven’t on yet. So when we say that babies and young children are at paying attention, what we really mean is that they’re bad at not paying attention. So they’re bad at rid of all the interesting things that could tell them something just looking at the thing that’s important. That’s the of attention, the kind of consciousness, that we might expect those butterflies who are designed to learn.
Well if we want think about a way of getting a taste of kind of baby consciousness as adults, I think the best is think about cases where we’re put in a new situation that we’ve never been before — when we fall in love with someone new, when we’re in a new city for the first time. And happens then is not that our consciousness contracts, it expands, so those three days in Paris seem to be more full of consciousness and experience than all the months being a walking, talking, faculty meeting-attending zombie back home. And by the way, that coffee, wonderful coffee you’ve been drinking downstairs, actually mimics the effect of those baby neurotransmitters. So what’s like 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 to be, it does tend to leave you waking up crying 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 do things like tie our shoelaces and the street 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 like those 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 like children.
(Applause)