What is going on in this baby’s mind? you’d asked people this 30 years ago, most people, psychologists, would have said that this baby was irrational, illogical, — that he couldn’t take the perspective of another person or understand cause and effect. In last 20 years, developmental science has completely overturned that picture. So in some ways, we that this baby’s thinking is like the thinking of the most scientists.
Let me give you just one example of this. One thing this baby could be thinking about, that could be going in his mind, is trying to figure out what’s on in the mind of that 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 thing of all is to figure out that other people think and feel isn’t actually exactly like what we think feel. Anyone who’s followed politics can testify to how 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 question is: could we ask them? Babies, after all, can’t talk, and if you ask a three year-old to you what he thinks, what you’ll get is a stream of consciousness monologue about ponies and birthdays and like that. So how do we actually ask them 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 give the babies two bowls of food: bowl of raw broccoli and one bowl of delicious goldfish crackers. all 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 liked it or she didn’t. So half the time, she as if she liked the crackers and didn’t like the broccoli — just a baby and any other sane person. But half the time, what she would do is a little bit of the broccoli and go, “Mmmmm, broccoli. I tasted the broccoli. Mmmmm.” And then 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 just the opposite of what the babies wanted. We did this with 15 and 18 month-old babies. then she would simply put her hand out and say, “Can you give me some?”
So the question is: would the baby give her, what they liked or what liked? And the remarkable thing was that 18 month-old babies, just barely walking talking, would give her the crackers if she liked the crackers, they would give her the broccoli if she liked the broccoli. the other hand, 15 month-olds would stare at her for a long time if she acted as she liked the broccoli, like they couldn’t figure this out. But after they stared for a long time, they would just her the crackers, what they thought everybody must like. So there two really remarkable things about this. The first one is these little 18 month-old babies have already discovered this really profound about human nature, that we don’t always want the same thing. what’s more, they felt that they should actually do to help other people get what they wanted.
Even more 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 more and learn more than ever would have thought. And this is just one 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 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 many ways, they’re worse than useless, because we have to put much time and energy into just keeping them alive. But if we turn to evolution for an answer 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 just us primates, also including other mammals, birds, even marsupials like kangaroos and wombats, it out that there’s a relationship between how long a a 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. one side is a New Caledonian crow. And crows other corvidae, ravens, rooks and so forth, are incredibly birds. They’re as smart as chimpanzees in some respects. this is a bird on the cover of science who’s learned how to use a tool get food. On the other hand, we have our friend the domestic chicken. And chickens and ducks 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 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 in the life 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 cover 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 kind of explanation could we have for this? Well animals, like the chicken, seem to be beautifully suited to doing 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 particular, but they’re extremely good at learning about laws of environments.
And of course, we human beings are way on the end of the distribution like the crows. We have bigger relative to our bodies by far than any other animal. We’re smarter, we’re more flexible, we can learn more, we survive in different environments, we migrated to cover the world and go to outer space. And our babies and children dependent on us for much longer than the babies of any other species. My son 23. (Laughter) And at least until they’re 23, we’re still popping those into those little open mouths.
All right, why would we see this correlation? Well an is that that strategy, that learning strategy, is an powerful, great strategy for getting on in the world, but it has one big disadvantage. And that big disadvantage is that, until you actually do all that learning, you’re going to helpless. So you don’t want to have the mastodon charging at and be saying to yourself, “A slingshot or maybe a might work. Which would actually be better?” You want to know all that before the actually show up. And the way the evolutions seems to have solved that is with a kind of division of labor. So the idea that we have 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 that we learned 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 that babies and young children are like the research and development division of the human species. So they’re protected blue sky guys who just have to go out and learn and have good ideas, we’re production and marketing. We have to take all those ideas that we learned we were children and actually put them to use. Another way of thinking about is instead of thinking of babies and children as being like defective grownups, should think about them as being a different developmental stage the same species — kind of like caterpillars and — except that they’re actually the brilliant butterflies who are flitting around garden and exploring, and we’re the caterpillars who are inching our narrow, grownup, adult path.
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If this 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 have really powerful mechanisms. And in fact, the baby’s brain seems to be the most powerful learning computer on the planet. real computers are actually getting to be a lot better. And there’s been a in our understanding of machine learning recently. And it all depends on the ideas this guy, the Reverend Thomas Bayes, who was a and mathematician 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 have a hypothesis that they think might be likely to start with. go out and test it against the evidence. The evidence makes change that hypothesis. Then they test that new hypothesis and so on and so forth. what Bayes showed was a mathematical way that you could do that. that mathematics is at the core of the best machine learning programs that we have now. And 10 years ago, I suggested that babies might be doing the thing.
So if you want to know what’s going on underneath beautiful brown eyes, I think it actually looks something like this. is Reverend Bayes’s notebook. So I think those babies actually making complicated calculations with conditional probabilities that they’re revising to figure out the world works. All right, now that might seem like an taller order to actually demonstrate. Because after all, if you ask grownups about statistics, they look extremely stupid. How could it be that are doing statistics?
So to test this we used a machine that have 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 mention just one that we did with Tumar Kushner, my student. If I showed you detector, you would be likely to think to begin with the way to make the detector go would be to put a block on top of detector. But actually, this detector works in a bit of a strange way. Because if wave a block over the top of the detector, something you wouldn’t think of to begin with, the detector will actually two out of three times. Whereas, if you do likely thing, put the block on the detector, it only activate two out of six times. So the unlikely hypothesis actually stronger evidence. It looks as if the waving is a more effective strategy than the other strategy. So did just this; we gave four year-olds this pattern evidence, and we just asked them to make it go. And sure enough, the four year-olds used evidence to wave the object on top of the detector.
Now there are two things that really interesting about this. The first one is, again, remember, are four year-olds. They’re just learning how to count. unconsciously, they’re doing these quite complicated calculations that will give them conditional probability measure. And the other interesting thing is that they’re using that to get to an idea, get to a hypothesis the world, that seems very unlikely to begin with. in studies we’ve just been doing in my lab, similar studies, we’ve show that four year-olds are actually at finding out an unlikely hypothesis than adults are we give them exactly the same task. So in these circumstances, the children are statistics to find out about the world, but after all, scientists also do experiments, and wanted to see if children are doing experiments. When children do experiments we it “getting into everything” or else “playing.”
And there’s been a bunch of interesting studies recently 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 Detectors. And what she did was show children that yellow made it go and red ones didn’t, and then she them an anomaly. And what you’ll see is that this boy will 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 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 this light up. (Laughter) I don’t know.
AG: Every scientist will recognize expression of despair.
(Laughter)
Boy: Oh, it’s because this needs to be like this, and needs to be like this.
AG: Okay, hypothesis two.
Boy: That’s why. Oh.
(Laughter)
AG: Now 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 the light only to here, not here. Oh, the bottom of this box has electricity in here, this doesn’t have electricity.
AG: Okay, that’s a fourth hypothesis.
Boy: It’s up. So when you put four. So you put on this one to make it light up and two on this one to it light up.
AG: Okay,there’s his fifth hypothesis.
Now that is a particularly — that is a adorable and articulate little boy, but what Cristine discovered is this is actually quite typical. If you look the way children play, when you ask them to 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 like to be this kind of creature? What’s it to be one of these brilliant butterflies who can five hypotheses in two minutes? Well, if you go back to those psychologists and philosophers, a lot of have said that babies and young children were barely conscious if they were conscious at all. And I just the opposite is true. I think babies and children are actually more conscious 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 that something’s relevant or important, we should pay attention it. Our consciousness of that thing that we’re attending to extremely bright and vivid, and everything else sort of goes dark. And we know something about the way the brain does this.
So what happens when pay attention is that the prefrontal cortex, the sort of executive part of our brains, sends a signal makes a little part 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. 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 good at taking in lots of from lots of different sources at once. And if you look in their brains, you see that they’re flooded these neurotransmitters that are really good at inducing learning 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 not paying attention. So they’re bad at getting rid all the interesting things that could tell them something and just at the thing that’s important. That’s the kind of attention, the kind of consciousness, that we might expect from butterflies who are designed to learn.
Well if we want to think about a of getting a taste of that kind of baby 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 for the first time. And what happens then is that our consciousness contracts, it expands, so that those three days in Paris seem be more full of consciousness and experience than all the months of a walking, talking, faculty meeting-attending zombie back home. And the way, that coffee, that wonderful coffee you’ve been drinking downstairs, actually the effect of those baby neurotransmitters. So what’s it like to be a baby? It’s like being love in Paris for the first time after you’ve had three double-espressos. (Laughter) That’s a way to be, but it does tend to leave you waking crying at three o’clock in the morning.
(Laughter)
Now it’s good be a grownup. I don’t want to say too about how wonderful babies are. It’s good to be a grownup. We can do like tie our shoelaces and cross the street by ourselves. it makes sense that we put a lot of effort into making babies think like do. But if what we want is to be 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)