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 was irrational, illogical, egocentric — that he couldn’t the perspective of another person or understand cause and effect. In the last 20 years, science has completely overturned that picture. So in some ways, we think that this baby’s is like the thinking of the most brilliant scientists.
Let me give just one example of this. One thing that this could be thinking about, that could be going on his mind, is trying to figure out what’s going in the mind of that other baby. After all, of the things that’s hardest for all of us do is to figure out what other people are thinking and feeling. maybe the hardest thing of all is to figure out that what people think and feel isn’t actually exactly like what we think and feel. Anyone who’s followed politics can 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 other people. Now the is: How could we ask them? Babies, after all, can’t talk, and if you ask a year-old to tell you what he thinks, what you’ll get is a beautiful stream of consciousness about ponies and birthdays and things like that. So how do we actually ask the question?
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Well it turns out that the secret was broccoli. What we did — Rapacholi, who was one of my students, and I — was to give the babies two bowls of food: one bowl of broccoli and one bowl of delicious goldfish crackers. Now of the babies, even in 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 she liked it or she didn’t. So half time, she acted as if she liked the crackers and didn’t like the broccoli — just like baby 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 little bit 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 this 15 and 18 month-old babies. And then she would 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 was that 18 month-old babies, just barely walking and talking, give her the crackers if she liked the crackers, but they would give her the if she liked the broccoli. On the other hand, 15 month-olds stare at her for a long time if she acted as if liked the broccoli, like they couldn’t figure this out. But then after they stared a long time, they would just give her the crackers, what they thought must like. So there are two really remarkable things about this. The first one is that little 18 month-old babies have already discovered this really profound fact about human nature, that we don’t want the same thing. And what’s more, they felt that they actually do things to help other people get what they wanted.
Even remarkably though, the fact that 15 month-olds didn’t do this that these 18 month-olds had learned this deep, profound fact about human nature in the three months when they were 15 months old. So children 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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question you might ask though is: Why do children learn much? And how is it possible for them to learn so in such a short time? I mean, after all, if you look at babies superficially, they pretty useless. And actually in many ways, they’re worse than useless, because we have to put so time and energy into just keeping them alive. But if 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, different species of animals, not just us primates, but also other mammals, birds, even marsupials like kangaroos and wombats, it turns out that there’s a relationship between long a childhood a species has and how big their are compared to their bodies and how smart and they are.
And sort of the posterbirds for this idea are the birds there. On one side is a New Caledonian crow. And and other corvidae, ravens, rooks and so forth, are smart birds. They’re as smart as chimpanzees in some respects. And this a bird on the cover of science who’s learned how to a tool to get food. On the other hand, we our friend the domestic chicken. And chickens and ducks and geese turkeys are basically as dumb as dumps. So they’re very, very good at pecking grain, and they’re not much good at doing anything else. Well turns 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 a of months. So childhood is the reason why the crows up on the cover of Science and the chickens end up in soup pot.
There’s something about that long childhood that seems to connected to knowledge and learning. Well what kind of explanation could we have this? Well some animals, like the chicken, seem to be beautifully suited to just one thing very well. So they seem to be beautifully suited to pecking grain in environment. Other creatures, like the crows, aren’t very good at doing anything in particular, but they’re extremely good learning about 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 far than any other animal. We’re smarter, we’re more flexible, we can 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 least they’re 23, we’re still popping those worms into those little mouths.
All right, why would we see this correlation? Well an idea that that strategy, that learning strategy, is an extremely powerful, great strategy for getting on in the world, it has one big disadvantage. And that one big is that, until you actually do all that learning, you’re to be helpless. So you don’t want to have mastodon charging at you and be saying to yourself, “A slingshot or maybe a spear 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 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 to do anything. All we have to do is learn. And as adults, we can take all those things that learned when we were babies and children and actually put them to to do things out there in the world.
So one way of thinking about it is babies and young children are like the research and division of the human species. So they’re the protected blue sky guys just have to go out and learn and have good ideas, we’re production and marketing. We have to take all those ideas we learned when we were children and actually put them to use. Another way of thinking about is instead of thinking of babies and children as being defective 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 are flitting around the garden and exploring, and we’re the who 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 they’re for — we might expect that they would really 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 getting be a lot better. And there’s been a revolution in our understanding of machine recently. And it all depends on the ideas of this guy, the Thomas Bayes, who was a statistician and mathematician in the 18th century. essentially what Bayes did was to provide a mathematical way using probability theory characterize, describe, the way that scientists find out about the world. what scientists 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 that hypothesis. Then they that new hypothesis and so on and so forth. And Bayes showed was a mathematical way that you could that. And that mathematics is at the core of the best machine learning programs that we have now. some 10 years ago, I suggested that babies might be doing same thing.
So if you want to know what’s on underneath those beautiful brown eyes, I think it actually looks like this. This is Reverend Bayes’s notebook. So I think those babies actually making complicated calculations with conditional probabilities that they’re revising to figure how the world works. All right, now that might seem like even taller order to actually demonstrate. Because after all, you ask even grownups about statistics, they look extremely stupid. How could it be that children 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 put some things on it and not others. And this very simple machine, my lab and others have done dozens of studies showing just how babies are at learning about the world. Let me just one that we 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 top the detector. But actually, this detector works in a bit of a strange way. if you wave a block over the top of the detector, something wouldn’t ever think of to begin with, the detector will actually activate two out of three times. Whereas, you do the likely thing, put the block on the detector, it will only activate out of six times. So the unlikely hypothesis actually has stronger evidence. It looks as if waving is a more effective strategy than the other strategy. So we did just this; we four year-olds this pattern of evidence, and we just asked them to make it go. sure enough, the four year-olds used the evidence to wave the object on top of the detector.
Now are two things that are really interesting about this. The first one is, again, remember, are four year-olds. They’re just learning how to count. But unconsciously, they’re doing these quite complicated that will give them a conditional probability measure. And the other interesting thing is they’re using that evidence to get to an idea, get to a about the world, that seems very unlikely to begin with. And in we’ve just been doing 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. 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 that have shown this around is really a kind of experimental research program. Here’s one Cristine Legare’s lab. What Cristine did was use our Detectors. And what she did was show children that yellow made it go and red ones didn’t, and then she showed them 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 hypothesis has just been falsified.
(Laughter)
Boy: This one lighted up, and this one nothing.
AG: Okay, he’s 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 this to be like this, and this needs to be this.
AG: Okay, hypothesis two.
Boy: That’s why. Oh.
(Laughter)
AG: Now this is next idea. He told the experimenter to do this, try putting it out onto the other location. Not working either.
Boy: Oh, because the light goes only here, not here. Oh, the bottom of this box electricity in here, but this doesn’t have electricity.
AG: Okay, that’s a hypothesis.
Boy: It’s lighting up. So when you put four. you put four on this one to make it light up and two on this one to make light up.
AG: Okay,there’s his fifth hypothesis.
Now that a particularly — that is a particularly adorable and articulate little boy, but what Cristine discovered 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. is actually pretty typical of four year-olds.
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Well, what’s it like to this kind of creature? What’s it like to be one of brilliant butterflies who 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 children were barely conscious if they were conscious at all. And I think just opposite is true. I think babies and children are actually more than we are as adults. Now here’s what we know about adult consciousness works. And adults’ attention and consciousness look of like a spotlight. So what happens for adults is we decide that something’s relevant important, we should pay attention to it. Our consciousness of that thing that we’re attending becomes 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 our brains, sends a signal that makes a little part of our much more flexible, more plastic, better at learning, and shuts down activity in all rest of our brains. So we have a very focused, purpose-driven kind of attention. If we at babies and young children, we see something very different. think babies and young children seem to have more of a lantern of consciousness a spotlight of consciousness. So babies and young children are very bad narrowing down to just one thing. But they’re very good at in lots of information from lots of different sources once. And if you actually look in their brains, you that they’re flooded with these neurotransmitters that are really good inducing learning and plasticity, and the inhibitory parts haven’t come on yet. So when we say babies and young children are bad at paying attention, what we mean is that they’re bad at not paying attention. 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 the kind attention, the kind of consciousness, that we might expect those butterflies who are designed to learn.
Well if we want to think about a way getting a taste of that kind of baby consciousness adults, I think the best thing is think about cases where we’re put in a new situation 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 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 the way, that coffee, that wonderful coffee you’ve been drinking downstairs, actually mimics the effect those baby neurotransmitters. So what’s it like to be baby? It’s like being in love in Paris for the first after you’ve had three double-espressos. (Laughter) That’s a fantastic way be, but it does tend to leave you waking up crying three o’clock in the morning.
(Laughter)
Now it’s good to a grownup. I don’t want to say too much about wonderful babies are. It’s good to be a grownup. We can do things tie our shoelaces and cross the street by ourselves. And it makes sense that we put a lot effort into making babies think like adults do. But if what we want is be like those butterflies, to have open-mindedness, open learning, imagination, creativity, innovation, maybe at some of the time we should be getting the to start thinking more like children.
(Applause)