What is going on in baby’s mind? If you’d asked people this 30 years ago, people, including psychologists, would have said that this baby irrational, illogical, egocentric — that he couldn’t take the perspective of another person or understand cause and effect. the last 20 years, developmental science has completely overturned that picture. in some ways, we think that this baby’s thinking like the thinking of the most brilliant scientists.
Let me give you just one example this. One thing that this baby could be thinking about, could be going on in his mind, is trying figure out what’s going on in the mind of other baby. After all, one of the things that’s hardest for all of us to do is to out what other people are thinking and feeling. And maybe the hardest thing of is to figure out that what other people think and feel isn’t actually 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 is: How could we ask them? Babies, after all, can’t talk, 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. how do we actually ask them the question?
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it turns out that the secret was broccoli. What did — Betty Rapacholi, who was one of my students, I — was actually to give the babies two bowls of food: one of raw broccoli and one bowl of delicious goldfish crackers. all of the babies, even in Berkley, like the and don’t like the raw broccoli. (Laughter) But then what Betty did was to a little taste of food from each bowl. And she would act as if she it or she didn’t. So half the time, she acted as if she the crackers and didn’t like the broccoli — just like a and any other sane person. But half the time, what would do is take a little bit of the and go, “Mmmmm, broccoli. I tasted the broccoli. Mmmmm.” And then she would take a little bit of 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 her hand out and say, “Can you give me some?”
So question is: What would the baby give her, what they liked or she liked? And 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 for a long time if she acted as if 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, what they everybody must like. So there are two really remarkable things about this. The first one 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, they that they should actually do things to help other people what they wanted.
Even more remarkably though, the fact 15 month-olds didn’t do this suggests that these 18 month-olds learned this deep, profound fact about human nature in the three months from when they were 15 old. So children both know more and learn more than ever would have thought. And this is just one of hundreds and hundreds of over the last 20 years that’s actually demonstrated it.
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The question you might though is: Why do children learn so much? And how it possible for them to learn so much in such a short time? I mean, all, if 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 just keeping them alive. But we turn to evolution for an answer to this puzzle of we spend so much time taking care of useless babies, it out that there’s actually an answer. If we look many, many different species of animals, not just us primates, but also other mammals, birds, even marsupials like kangaroos and wombats, it turns that there’s a relationship between how long a childhood species has and how big their brains are compared to their bodies and how smart flexible they are.
And sort of the posterbirds for this idea are the birds up there. On side is a New Caledonian crow. And crows and other corvidae, ravens, rooks and so forth, are smart birds. They’re as smart as chimpanzees in some respects. And this is a bird the cover of science who’s learned how to use a tool to get food. On other hand, we have our friend the domestic chicken. And and ducks and geese and turkeys are basically as dumb as dumps. they’re very, 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 babies, are fledglings. They depend on their moms to drop in their little open mouths for as long as two years, which is a long time in the 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 chickens end up in the soup pot.
There’s something about that long that seems to be connected to knowledge and learning. what kind of explanation could we have for this? some animals, like the chicken, seem to be beautifully suited to doing just thing very well. So they seem to be beautifully suited to pecking grain one environment. Other creatures, like the crows, aren’t very good at anything in particular, but they’re extremely good at learning laws of different environments.
And of course, we human beings way out on the end of the distribution like crows. We have bigger brains relative to our bodies by than any other animal. We’re smarter, we’re more flexible, we learn more, we survive in more different environments, we migrated cover the world and even go to outer space. And our babies and are dependent on us for much longer than the babies of any species. My son is 23. (Laughter) And at least until they’re 23, we’re popping those worms into those little open mouths.
All right, would we see this correlation? Well an idea is that strategy, that learning strategy, is an extremely powerful, great strategy for on in the world, but it has one big disadvantage. 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 maybe a spear might work. Which would actually be better?” want to know all that before the mastodons actually up. And the way the evolutions seems to have solved that is with a kind of division of labor. So the idea is that we this early period when we’re completely protected. We don’t have to do anything. All 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 the research and development division of the human species. So they’re protected blue sky guys who just have to go and learn and have good ideas, and we’re production marketing. We have to take all those ideas that we when we were children and actually put them to use. way of thinking about it is instead of thinking babies and children as being like defective grownups, we should about them as being a different developmental stage of the species — kind of like caterpillars and butterflies — except that they’re actually the brilliant who are flitting around the garden and exploring, and we’re the caterpillars are inching along our narrow, grownup, adult path.
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If is true, if these babies are designed to learn — this evolutionary story would say children are for learning, that’s what they’re for — we might expect that would have really powerful learning mechanisms. And in fact, the baby’s brain seems to be the most powerful computer on the planet. But real computers are actually getting to be a better. And there’s been a revolution in our understanding of machine learning recently. it all depends on the ideas of this guy, the Reverend Thomas Bayes, who was a statistician and in the 18th century. And essentially what Bayes did was to provide a mathematical using probability theory to characterize, describe, the way that scientists find out about the world. So what do is they have a hypothesis that they think might be likely to start with. go out and test it against the evidence. The evidence makes them change hypothesis. Then they test that new hypothesis and so and so forth. And what Bayes showed was a mathematical that 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 babies be doing the same thing.
So if you want to know what’s going on those beautiful brown eyes, I think it actually looks something this. This is Reverend Bayes’s notebook. So I think those babies are actually making complicated calculations with conditional 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 that children are doing statistics?
So to test this we used a machine that we called the Blicket Detector. This is a box that lights and plays music when you put some things on and not others. And using this very simple machine, lab and others have done dozens of studies showing just good babies are at learning about the world. Let me just one that we did with Tumar Kushner, my student. If showed you this detector, you would be likely to think to begin that the way to make the detector go would be put a block on top of the detector. But actually, this detector works in a of a strange way. Because if you wave a block over top of the detector, something you wouldn’t ever think of to begin with, the detector actually activate two out of three times. Whereas, if you do likely thing, put the block on the detector, it will only two out of six times. So the unlikely hypothesis actually has stronger evidence. It looks if the waving is a more effective strategy than the strategy. So we did just this; we gave four year-olds pattern of evidence, and we just asked them to make it go. And enough, the four year-olds used the evidence to wave the on top of the detector.
Now there are two things that are really interesting about this. The 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 will give them a conditional probability measure. the other interesting thing is that they’re using that evidence to get to idea, get to a hypothesis about the world, that seems very unlikely to begin with. And studies we’ve just been doing in my lab, similar studies, we’ve that four year-olds are actually better at finding out an hypothesis than adults are when we give them exactly the same task. So in these circumstances, children are using statistics to find out about the world, but after all, 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 recently that have this playing around is really a kind of experimental 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 them 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 first hypothesis has just 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) I don’t know.
AG: scientist will recognize that expression of despair.
(Laughter)
Boy: Oh, it’s because this needs to be 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 do this, to try 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 electricity here, but this doesn’t have electricity.
AG: Okay, that’s a fourth hypothesis.
Boy: It’s lighting up. So you put four. So you put four on this one to make it light up two on this 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. you look at the way children play, when you ask them 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 be kind of creature? What’s it like to be one of these brilliant butterflies who test five hypotheses in two minutes? Well, if you go back to those and philosophers, a lot of them have said that babies and young children were barely conscious if were conscious at all. And I think just the opposite is true. I think and children are actually more conscious than we are as adults. Now here’s what know about how adult consciousness works. And adults’ attention consciousness look kind of like a spotlight. So what happens adults is we decide 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 way brain does this.
So what happens when we pay attention is that the prefrontal cortex, the of executive part of our brains, sends a signal that makes a little of our brain much more flexible, more plastic, better learning, and shuts down activity in all the rest our brains. So we have a very focused, purpose-driven kind of attention. we look at babies and young children, we see something very different. I think and young children seem to have more of a of consciousness than a spotlight of consciousness. So babies and children are very bad at narrowing down to just one thing. But they’re very at taking in lots of information from lots of different sources at once. if you actually look in their brains, you see they’re flooded with these neurotransmitters that are really good at learning and plasticity, and the inhibitory parts haven’t come on yet. 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. they’re bad at getting rid of all the interesting that could tell them something and just looking at thing that’s important. That’s the kind of attention, the kind consciousness, that we might expect 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, think the best thing is think about cases where we’re put in a new that we’ve never been in before — when we fall love with someone new, or when we’re in a new city the first time. And what happens then is not that our contracts, it expands, so that those three days in Paris to be more full of consciousness and experience than all the of being 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 a baby? It’s like being in love in Paris the first time after you’ve had three double-espressos. (Laughter) That’s a fantastic way to be, but it does tend 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 about how babies are. It’s good to be a grownup. We do things like tie our shoelaces and cross the by ourselves. And it makes sense that we put a lot of effort into making babies 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 of the time we should be getting the adults to start more like children.
(Applause)