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 of another person or understand cause effect. In the last 20 years, developmental science has overturned that picture. So in some ways, we think that 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 going on in mind of that other baby. After all, one of the that’s hardest for all of us to do is figure out what other people are thinking and feeling. maybe the hardest thing of all is to figure out what other people think and feel isn’t actually exactly what we think and feel. Anyone who’s followed politics can testify how hard that is for some people to get. wanted to know if babies and young children could understand this really profound thing other people. Now the question is: How could we ask them? Babies, all, can’t talk, and if you ask a three year-old tell you what he thinks, what you’ll get is a beautiful stream consciousness monologue about ponies and birthdays and things like that. So do we actually ask them the question?
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Well turns out that the secret was broccoli. What we did — Rapacholi, who was one of my students, and I — 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 crackers don’t like the raw broccoli. (Laughter) But then what Betty did to take a little taste of food from each bowl. And she would act as she liked it or she didn’t. So half the time, she as if she liked the crackers and didn’t like the — just like a baby and any other sane person. But half the time, what she would is take a little bit of the broccoli and go, “Mmmmm, broccoli. I the broccoli. Mmmmm.” And then she would take a little of the crackers, and she’d go, “Eww, yuck, crackers. I the crackers. Eww, yuck.” So she’d act as if she wanted was just the opposite of what the babies wanted. did this with 15 and 18 month-old babies. And then she simply put her hand out and say, “Can you give me some?”
So the is: What would the baby give her, what they liked or what liked? And the remarkable thing was that 18 month-old babies, just walking and talking, would give her the crackers if she liked the crackers, but they give her the broccoli if she liked the broccoli. On the other hand, 15 month-olds would stare her for a long time if she acted as if she liked the broccoli, like couldn’t figure this out. But then after they stared for a long time, they would just give the crackers, what they thought everybody must like. So there are two really remarkable about this. The first one is that these little 18 month-old have already discovered this really profound fact about human nature, that we don’t always want same thing. And what’s more, they felt that they should actually do things to help other people get they wanted.
Even more remarkably though, the fact that 15 month-olds didn’t do this suggests that 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 more and learn more than we ever would have thought. And is just one of hundreds and hundreds of studies the last 20 years that’s actually demonstrated it.
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The question might ask though is: Why do children learn so much? how is it possible for them to learn so in such a short time? I mean, after all, 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 keeping them alive. But if we turn to evolution for an answer this puzzle of why we spend so much time taking of useless babies, it turns out that there’s actually an answer. we look across many, many different species of animals, not just us primates, but also other mammals, birds, even marsupials like kangaroos and wombats, turns out that there’s a relationship between how long a childhood a species has and how their brains are compared to their bodies and how smart and they are.
And sort of the posterbirds for this idea are birds up there. On one side is a New Caledonian crow. crows and other corvidae, ravens, rooks and so forth, are smart birds. They’re as smart as chimpanzees in some respects. And is a bird on the cover of science who’s learned how to use tool to get food. On the other hand, we have friend the domestic chicken. And chickens and ducks and and 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 it turns that 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 long time in the life of a bird. Whereas the are actually mature within a couple of months. So childhood is the reason why the crows end up the cover of Science and the chickens end up in soup pot.
There’s something about that long childhood that seems to be connected to knowledge and learning. what kind of explanation could we have for this? Well some animals, like chicken, seem to be beautifully suited to doing just thing very well. So they seem to be beautifully suited pecking grain in one environment. Other creatures, like the crows, aren’t very good at doing in particular, but they’re extremely good at learning about laws different environments.
And of course, we human beings are way out on the of the distribution like the crows. We have bigger relative to our bodies by far than any other animal. We’re smarter, we’re flexible, we can learn more, we survive in more different environments, we migrated cover the world and even go to outer space. And our and children are dependent on us for much longer than the babies of other species. My son 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 see correlation? Well an idea is that that strategy, that strategy, is an extremely powerful, great strategy for getting on in world, but it has one big disadvantage. And that one disadvantage is that, until you actually do all that learning, you’re going to be helpless. So you don’t to have the mastodon charging at you and be saying to yourself, “A slingshot or maybe spear might work. Which would actually be better?” You want to all that before the mastodons actually show up. And way the evolutions seems to have solved that problem is with a of division of labor. So the idea is that we have this early when we’re completely protected. We don’t have to do anything. All we have to do is learn. then as adults, we can take all those things that we learned when were babies and children and actually put them to work to do things out there the world.
So one way of thinking about it that babies and young children are like the research development division of the human species. So they’re the blue sky guys who just have to go out learn and have good ideas, and we’re production and marketing. We have to take those ideas that we learned when we were children 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 developmental stage of the same species — kind of caterpillars and butterflies — except that they’re actually the brilliant butterflies who are flitting the garden and exploring, and we’re the caterpillars who inching along our narrow, grownup, adult path.
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this is true, if these babies are designed to — and this evolutionary story would say children are 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 be the most powerful learning computer on the planet. real computers are actually getting to be a lot better. And there’s a revolution in our understanding of machine learning recently. And all depends on the ideas of this guy, the Reverend Bayes, who was a statistician and mathematician in the 18th century. And essentially what did was to provide a mathematical way using probability theory to characterize, describe, the way that find out about the world. So what scientists do is they have 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 so on and so forth. And what Bayes showed was a mathematical way that could do that. And that mathematics is at the core of the best learning programs that we have now. And some 10 years ago, suggested that babies might be doing the same thing.
So if want to know what’s going on underneath those beautiful brown eyes, I think it actually something like this. This is Reverend Bayes’s notebook. So I think babies are actually making complicated calculations with conditional probabilities that they’re to figure out how the world works. All right, now that might like an even taller order to actually demonstrate. Because after all, if you ask even 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 up and plays music when you put some things it and not others. And using this very simple machine, my 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 put a block on top of the detector. But actually, this works in a bit of a strange way. Because if you a block over the top of the detector, something wouldn’t ever think of to begin with, the detector will activate two out of three times. Whereas, if you do the thing, put the block on the detector, it will activate two out of six times. So the unlikely hypothesis actually has evidence. It looks as if the waving is a more effective strategy than the strategy. So we 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 the object on top of the detector.
Now there are two things that really interesting about this. The first one is, again, remember, these are four year-olds. They’re just how to count. But unconsciously, they’re doing these quite complicated calculations that give them a conditional probability measure. And the other interesting is that 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 studies we’ve just been doing my lab, similar studies, we’ve show that four year-olds are actually better at out an unlikely hypothesis than adults are when we them exactly the same task. So in these circumstances, the children are using to find out about the world, but after all, scientists also do experiments, and we wanted see if children are doing experiments. When children do experiments we call it “getting everything” or else “playing.”
And there’s been a bunch of interesting studies recently that 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. And she did was show children that yellow ones made go and red ones didn’t, and then she showed an anomaly. And what you’ll see is that this little boy will through five hypotheses in the space of two minutes.
(Video) Boy: How about this? Same as the side.
Alison Gopnik: Okay, so his first hypothesis has been falsified.
(Laughter)
Boy: This one lighted up, and this one nothing.
AG: Okay, he’s got experimental notebook out.
Boy: What’s making this light up. (Laughter) don’t know.
AG: Every scientist will recognize that expression despair.
(Laughter)
Boy: Oh, it’s because this needs to be like this, and this to be like this.
AG: Okay, hypothesis two.
Boy: That’s why. Oh.
(Laughter)
AG: Now this is his idea. He told the experimenter to do this, to putting it out onto the other location. Not working either.
Boy: Oh, because the light goes only to here, here. Oh, the bottom of this box has electricity here, but this doesn’t have electricity.
AG: Okay, that’s fourth hypothesis.
Boy: It’s lighting up. So when you put four. So you four on this one to make it light up and on this one to make it light up.
AG: Okay,there’s his fifth hypothesis.
Now that is a particularly — 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, what they do is do a series of experiments. This is actually pretty typical four year-olds.
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Well, what’s it like to be this kind of creature? What’s it to be one of these brilliant butterflies who can test five hypotheses in two minutes? Well, if you back to those psychologists and philosophers, a lot of them have said that babies and young were barely conscious if they were conscious at all. And I think just the opposite is true. think babies and children are actually more conscious than are as adults. Now here’s what we know about how adult works. And adults’ attention and consciousness look kind of like a spotlight. So what for adults is we decide that something’s relevant or important, we pay attention to it. Our consciousness of that thing we’re attending to becomes extremely bright and vivid, and everything sort of goes dark. And we even know something the way the brain does this.
So what happens when we pay attention is that the cortex, the sort of executive part of our brains, a signal that makes a little part of our brain much flexible, more plastic, better at learning, and shuts down activity in all the rest of our brains. we have a very focused, purpose-driven kind 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 of consciousness than a spotlight of consciousness. So babies and young children are very bad narrowing down to just one thing. But they’re very good at taking in lots of information from lots different sources at once. And if you actually look in their brains, see 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 babies and young children are bad at paying attention, what really mean is that they’re bad at not paying attention. So they’re bad getting rid of all the interesting things that could tell them something and just at the thing that’s important. That’s the kind of attention, kind of consciousness, that we might expect from those butterflies who are to learn.
Well if we want to think about a way of getting a taste of that of baby consciousness as adults, I think the best thing is think about cases we’re put in a new situation that we’ve never been in — when we fall in love with someone new, or when we’re in a new for 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 months of a walking, talking, faculty meeting-attending zombie back home. And the way, that coffee, that wonderful coffee you’ve been downstairs, actually mimics the effect of those baby neurotransmitters. So what’s it like to be baby? It’s like being in love in Paris for first time after you’ve had three double-espressos. (Laughter) That’s a fantastic to be, but it does tend to leave you waking up crying three o’clock in the morning.
(Laughter)
Now it’s good be a grownup. I don’t want to say too much about how babies are. It’s good to be a grownup. We can do things like tie our shoelaces and cross street by ourselves. And it makes sense that we a lot of effort into making babies think like do. But if what we want is to be like those butterflies, 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)