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 person or understand cause and effect. In the last 20 years, developmental science has 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 baby could thinking about, that could be going on in his mind, is trying to figure out what’s going on the mind of that other baby. After all, one the things that’s hardest for all of us to do to figure out what other people are thinking and feeling. And maybe hardest thing of all is to figure out that other people think and feel isn’t actually exactly like what we think and feel. Anyone who’s followed can testify to how hard that is for some people to get. We wanted know if babies and young children could understand this really profound about other people. Now the question is: How could we them? Babies, after all, can’t talk, and if you ask three year-old to tell you what he thinks, what you’ll get is a beautiful stream of consciousness monologue ponies and birthdays and things like that. So how do we actually ask them the question?
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it turns out that the secret was broccoli. What we did — Betty Rapacholi, who was one my students, and I — was actually 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 don’t like the raw broccoli. (Laughter) But then what did was to take a little taste of food from each bowl. she would act as if she liked it or she didn’t. So half the time, she acted if she liked the crackers and didn’t like the broccoli — just like a baby any other sane person. But half the time, what she would do take a little bit of the broccoli and go, “Mmmmm, broccoli. I tasted the broccoli. Mmmmm.” And then she would a little bit of the crackers, and she’d go, “Eww, yuck, crackers. I the crackers. Eww, yuck.” So she’d act as if what she 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 me some?”
So the question is: What would the baby give her, what they or what she liked? And the remarkable thing was that 18 month-old babies, barely walking and talking, would give her the crackers if she liked the crackers, but would give her the broccoli if she liked the broccoli. On the other hand, 15 month-olds would stare at for a long time if she acted as if she the broccoli, like they couldn’t figure this out. But then they stared 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 one is that these little 18 month-old babies have already discovered this profound fact about human nature, that we don’t always the same thing. And what’s more, they felt that they should do things to help other people get what they wanted.
Even more remarkably though, the fact 15 month-olds didn’t do this suggests that these 18 month-olds had learned this deep, profound fact about human 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 just one of hundreds and hundreds of studies over the 20 years that’s actually demonstrated it.
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The question you might ask though is: do children learn so much? And how is it possible for them to so much in such a short time? I mean, all, if you look at babies superficially, they seem pretty useless. And actually many ways, they’re worse than useless, because we have to put so time and energy into just keeping them alive. But we turn to evolution for an answer to this puzzle of why spend so much time taking care of useless babies, it turns that there’s actually an answer. If we look across many, many 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 childhood a species has and how big their brains are compared to bodies and how smart and flexible they are.
And sort of the for this idea are the birds up there. On side is a New Caledonian crow. And crows and other corvidae, ravens, and so forth, are incredibly smart birds. They’re as smart chimpanzees in some respects. And this is a bird on the cover of science who’s learned how use a tool to get food. On the other hand, have our friend the domestic chicken. And chickens and ducks and geese and turkeys are basically as dumb 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 in their little open for as long as two years, which is a really long time in the life a bird. Whereas the chickens are actually mature within couple of months. So childhood is the reason why crows end up on the cover of Science and the chickens end up in soup pot.
There’s something about that long childhood that seems be connected to knowledge and learning. Well what kind of explanation could we have for this? some animals, like the chicken, seem to be beautifully suited to doing just one very well. So they seem to be beautifully suited to pecking grain in one environment. Other creatures, the crows, aren’t very good at doing anything in particular, but they’re extremely good at learning about laws different environments.
And of course, we human beings are way out the end of the distribution like the crows. We have bigger brains 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, migrated to cover the world and even go to outer space. And babies and children are dependent on us for much longer the babies of any other species. My son is 23. (Laughter) And least until they’re 23, we’re still popping those worms into those open mouths.
All right, why would we see this 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 big disadvantage is that, you actually do all that learning, you’re going to be helpless. you don’t want to have the mastodon charging at you and be to yourself, “A slingshot or maybe a spear might work. Which actually be better?” You want to know all that before mastodons actually show up. And the way the evolutions seems have solved that problem is with a kind of division 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 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 work 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 development division of the species. So they’re the 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. Another way thinking about it is instead of thinking of babies and children being like defective grownups, we should think about them as being a different stage of the same species — kind of like caterpillars and — 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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If this is true, if these babies are designed 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 mechanisms. And in fact, the baby’s brain seems to be most powerful learning computer on the planet. But real computers actually getting to be a lot better. And there’s been revolution in our understanding of machine learning recently. And it depends on the ideas of this guy, the Reverend Thomas Bayes, who was a and mathematician 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 scientists do is they have a hypothesis that they think might be likely to with. They go out and test it against the evidence. The makes them change that hypothesis. Then they test that hypothesis and so on and so forth. And what Bayes showed was a mathematical way that you do that. And that mathematics is at the core the best machine learning programs that we have now. And some 10 ago, I suggested that babies might be doing the thing.
So if you want to know what’s going on underneath those beautiful brown eyes, I think it looks something like this. This is Reverend Bayes’s notebook. So I think those babies actually making complicated calculations with conditional probabilities that they’re revising figure out how the world works. All right, now that might seem like an even taller to actually demonstrate. Because after all, if you ask even about statistics, they look extremely stupid. How could it be children are doing statistics?
So to test this we used a machine that we have called Blicket Detector. This is a box that lights up and plays music when you put some on it and not others. And using this very machine, my lab and others have done dozens of studies just how good babies are at learning about the world. Let mention just one that we did with Tumar Kushner, my student. If I you this detector, you would be likely to think begin with that the way to make the detector go would be to put block on top of the detector. But actually, this detector in a bit of a strange way. Because if wave a block over the top of the detector, something you wouldn’t ever think of to begin with, detector will actually activate two out of three times. Whereas, if you the likely thing, put the block on the detector, it will only activate out of six times. So the unlikely hypothesis actually stronger evidence. It looks as if the waving is more effective strategy than the other strategy. So we just this; we gave four year-olds this pattern of evidence, we just asked them to make it go. And sure enough, the four year-olds used the to wave the object on top of the detector.
Now there are two things that are really about this. The first one is, again, remember, these are year-olds. They’re just learning how to count. But unconsciously, they’re doing these quite calculations that will give them a conditional probability measure. And other interesting thing is that they’re using that evidence get to an idea, get to a hypothesis about the world, that seems very unlikely to begin with. in studies we’ve just been doing in my lab, similar studies, we’ve that four year-olds are actually better at finding out an unlikely hypothesis adults 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 do experiments, and wanted to 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 from Cristine Legare’s lab. Cristine did was use our Blicket Detectors. And what she did was show that yellow ones made it go and red ones didn’t, and then she showed them an anomaly. And you’ll see is that this little boy will go through five in the space of two minutes.
(Video) Boy: How this? Same as the other side.
Alison Gopnik: Okay, so first hypothesis has just been falsified.
(Laughter)
Boy: This one lighted up, this one nothing.
AG: Okay, he’s got his experimental notebook out.
Boy: What’s making light 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, two.
Boy: That’s why. Oh.
(Laughter)
AG: Now this his 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 only to here, not here. Oh, the bottom of this box has electricity in here, but doesn’t have electricity.
AG: Okay, that’s a fourth hypothesis.
Boy: It’s lighting up. So when you put four. you put four on this one to make it light and two on this one to make it light up.
AG: Okay,there’s fifth hypothesis.
Now that is a particularly — that is particularly adorable and articulate little boy, but what Cristine discovered is is actually quite typical. If you look at the way children play, when you ask them explain something, what 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 to be this kind of creature? What’s it like to be one of these brilliant butterflies who test five hypotheses in two minutes? Well, if you back to those psychologists and philosophers, a lot of them have said babies and young children were barely conscious if they were at all. And I think just the opposite is true. I think babies and are actually more conscious than we are as adults. Now here’s what know about how adult consciousness works. And adults’ attention and consciousness look of like a spotlight. So what happens for adults we decide that something’s relevant or important, we should pay to it. Our consciousness of that thing that we’re to becomes extremely bright and vivid, and everything else of goes dark. And we even know something about the way the brain does this.
So what happens we pay attention is that the prefrontal cortex, the sort of executive part of our brains, sends a that makes a little part of our brain much flexible, more plastic, better at learning, and shuts down in all the rest of our brains. So we 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 lantern of consciousness than a spotlight of consciousness. So babies and young are very bad at narrowing down to just one thing. But they’re very good at taking lots of information from lots of different sources at once. And if you look in their brains, you see that they’re flooded with these that are really good at inducing learning and plasticity, the inhibitory parts haven’t come on yet. So when say that babies and young children are bad at paying attention, what we really mean that they’re bad at not paying attention. So they’re bad at getting rid of all the interesting that 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 from those butterflies who are to learn.
Well if we want to think about way of getting a taste of that kind of baby as adults, I think the best thing is think cases where we’re put in a new situation that we’ve never been in — when we fall in love with someone new, when we’re in a new city for the first time. And what happens then is that our consciousness contracts, it expands, so that those days in 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 by the way, that coffee, 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 time after you’ve three double-espressos. (Laughter) That’s a fantastic way to be, but it tend to leave you waking up crying at three o’clock the morning.
(Laughter)
Now it’s good to be a grownup. I don’t want to say much about how wonderful babies are. It’s good to be grownup. We can do things like tie our shoelaces cross the street by ourselves. And it makes sense we put a lot of effort into making babies think like adults do. But what we want is to be like those butterflies, to open-mindedness, open learning, imagination, creativity, innovation, maybe at least some of the we should be getting the adults to start thinking more children.
(Applause)