What is going on in this baby’s mind? If you’d people this 30 years ago, most people, including psychologists, would have said this baby was irrational, illogical, egocentric — that he couldn’t take the perspective of another person or cause and effect. In the last 20 years, developmental science has completely overturned that picture. So in ways, we think that this baby’s thinking is like the thinking of the brilliant scientists.
Let me give you just one example this. One thing that this baby could be thinking about, that be going on in his mind, is trying to figure out what’s on in the mind of that other baby. After all, one of the that’s hardest for all of us to do is to figure out what people are thinking and feeling. And maybe the hardest thing of all is to figure that what 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 know if babies and young children could understand this profound thing about other people. Now the question is: How could we them? Babies, after all, can’t talk, and if you a three year-old to 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 it turns 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 food: one bowl of raw broccoli and one bowl delicious goldfish crackers. Now all of the babies, even in Berkley, the crackers and don’t like the raw broccoli. (Laughter) But what Betty did was to take a little taste of 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 didn’t like the broccoli — just like a baby and any other sane person. half the time, what she would do is take a bit of the broccoli and go, “Mmmmm, broccoli. I the broccoli. Mmmmm.” And then she would take a little bit of crackers, and she’d go, “Eww, yuck, crackers. I tasted the crackers. Eww, yuck.” So she’d as if what she wanted was just the opposite of what the wanted. We did this with 15 and 18 month-old babies. And then she would simply put hand out and say, “Can you give me some?”
So question is: What would the baby give her, what they liked or what liked? And the remarkable thing was that 18 month-old babies, just barely walking and talking, would give her crackers if she liked the crackers, but they would give her broccoli if she liked the broccoli. On the other hand, 15 month-olds would stare at her 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 just give her the crackers, what they thought everybody like. So there are two really remarkable things about this. The first one is that these little 18 month-old have already discovered this really profound fact about human nature, we don’t always want the same thing. And what’s more, they felt that they actually do things to help other people get what wanted.
Even more remarkably though, the fact that 15 month-olds didn’t this suggests that these 18 month-olds had learned this deep, profound fact about human nature in three months from when they were 15 months old. So both know more and learn more than we ever would have thought. And this is just of hundreds and hundreds of studies over 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? And how is it for them to learn so much in such a time? I mean, after all, if you look at superficially, they seem pretty useless. And actually in many ways, they’re worse than useless, because we to put so much time and energy into just keeping them alive. But if we to evolution for an answer to this puzzle of why we spend so much time taking care useless babies, it turns out that there’s actually an answer. If we across many, many different species of animals, not just primates, but also including other mammals, birds, even marsupials like kangaroos and wombats, it turns out that there’s relationship between how long a childhood a species has and how their brains are compared to their bodies and how smart and flexible they are.
And sort 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 forth, are incredibly smart 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 to get food. On the other hand, we have our friend the chicken. And chickens and ducks and geese and turkeys are basically as dumb as dumps. they’re very, very good at pecking for grain, and they’re much good at doing anything else. Well it turns that the babies, the New Caledonian crow babies, are fledglings. They depend their moms to drop worms in their little open mouths for as long two years, which is a really long time in the life of a bird. the chickens are actually mature within a couple of months. So childhood is the reason why the end up on the cover of Science and the chickens end in the soup pot.
There’s something about that long childhood that seems to be connected knowledge and learning. Well what kind of explanation could we for this? Well some animals, like the chicken, seem to be beautifully suited doing just one thing very well. So they seem to be 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 learning about laws of different environments.
And of course, we human beings are way out on the end the distribution like the crows. We have bigger brains relative our bodies by far than any other animal. We’re smarter, we’re more flexible, we can learn more, survive in more different environments, we migrated to cover the and even go to outer space. And our babies and are dependent on us for much longer than the of any other species. My son is 23. (Laughter) at least until they’re 23, we’re still popping those into those little open mouths.
All right, why would we this correlation? Well an idea is that that strategy, learning strategy, is an extremely powerful, great strategy for on in the world, but it has one big disadvantage. And one big disadvantage is that, until you actually do that learning, you’re going to be helpless. So you don’t want to have the mastodon charging you and be saying to yourself, “A slingshot or maybe a spear work. Which would actually be better?” You want to know all that before the mastodons show up. And the way the evolutions seems to have solved that is with a kind of division of labor. So the idea is that have this early period when we’re completely protected. We don’t to do anything. All we have to do is learn. And then as adults, can take all those things that we learned when we were babies and children and actually put them work to do things out there in the world.
So way of thinking about it is that babies and young are like the research and development division of the human species. So they’re the protected sky guys who just have to go out and learn and have ideas, and we’re production and marketing. We have to take those ideas that we learned when we were children and put them to use. Another way of thinking about it is instead of thinking of babies children as being like defective grownups, we should think about them as being a different stage of the same species — kind of like caterpillars and butterflies — that they’re actually the brilliant butterflies who are flitting around the garden and exploring, we’re the caterpillars who are inching along our narrow, grownup, adult path.
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If is true, if these babies are designed to learn — and evolutionary story would say children are for learning, that’s they’re for — we might expect that they would have really powerful learning mechanisms. in fact, the baby’s brain seems to be the most powerful learning computer the planet. But real computers are actually getting to a lot better. And there’s been a revolution in understanding of machine learning recently. And it all depends on the ideas of this guy, the Reverend Bayes, who was a statistician and mathematician in the 18th century. And essentially Bayes did was to provide a mathematical way using probability theory characterize, describe, the way that scientists find out about world. So what scientists do is they have a that they think might be likely to start with. They go and test it against the evidence. The evidence makes them change that hypothesis. Then test that new hypothesis and so on and so forth. And what Bayes showed was mathematical way that you could do that. And that mathematics is at the core of the best machine programs that we have now. And some 10 years ago, I suggested that might be doing the same thing.
So if you want know what’s going on underneath those beautiful brown eyes, I think it actually looks something like this. This Reverend Bayes’s notebook. So I think those babies are actually making complicated calculations with conditional probabilities they’re revising to figure out how the world works. All right, now that seem like an even taller order to actually demonstrate. Because all, if you ask even grownups about statistics, they look stupid. How could it be that children are doing statistics?
So to test we used a machine that we have called the 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 showing just how good are at learning about the world. Let me mention just that we did with Tumar Kushner, my student. If I showed you this detector, would be likely to think to begin with that the way to make the detector go would to put a block on top of the detector. But actually, this works in a bit of a strange way. Because if wave a block over the top of the detector, you wouldn’t ever think of to begin with, the detector will activate two out of three times. Whereas, if you do the likely thing, put the block on detector, it will only activate two out of six times. So the hypothesis actually has stronger evidence. It looks as if the waving is more effective strategy than the other strategy. So we did just this; we gave four year-olds pattern of evidence, and we just asked them to it go. And sure enough, the four year-olds used evidence to wave the object on top of the detector.
Now there are things that are really interesting about this. The first one is, again, remember, these are four year-olds. They’re learning how to count. But unconsciously, they’re doing these quite complicated calculations will give them a conditional probability measure. And the other interesting thing is that they’re using that to get to an idea, get to a hypothesis about the world, that seems very to begin with. And in studies we’ve just been doing in my lab, similar studies, we’ve show four year-olds are actually better at finding out an unlikely than adults are when we give them exactly the same task. So these circumstances, the children are using statistics to find out about the world, but after all, scientists do experiments, and we wanted to see if children are doing experiments. children do experiments we call it “getting into everything” or “playing.”
And there’s been a bunch of interesting studies recently that have this playing around is really a kind of experimental research program. Here’s from Cristine Legare’s lab. What Cristine did was use our Blicket Detectors. And she did was show children that yellow ones made it go red ones didn’t, and then she showed them an 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 first hypothesis has just been falsified.
(Laughter)
Boy: This one lighted up, this one nothing.
AG: Okay, he’s got his experimental out.
Boy: What’s making this light up. (Laughter) I don’t know.
AG: Every will recognize that expression of despair.
(Laughter)
Boy: Oh, it’s this needs to be like this, and this needs to like 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 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 four. So you put four on this one to it light up and two on this one to it 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 is this actually quite typical. If you look at the way children play, you ask them to explain something, what they really do is 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 creature? What’s it like to be one of these brilliant butterflies who can five hypotheses in two minutes? Well, if you go back 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. think babies and children are actually more conscious than are as adults. Now here’s what we know about how consciousness works. And adults’ attention and consciousness look kind like a spotlight. So what happens for adults is 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 sort of goes dark. And we even know something about the the brain does this.
So what happens when we pay attention that the prefrontal cortex, the sort of executive part our brains, sends 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 brains. So we have a very focused, purpose-driven kind of attention. If we look babies and young children, we see something very different. I think babies and young seem to have more of a lantern of consciousness than a of consciousness. So babies and young children are very bad at down to just one thing. But they’re very good at taking in lots of information lots of different sources at once. And if you actually look in their brains, you see they’re flooded with these neurotransmitters that are really good at inducing learning and plasticity, the inhibitory parts haven’t come on yet. So when we say 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 of all the interesting things that could tell them something and just looking at the that’s important. That’s the kind of attention, the kind of consciousness, that we might expect those butterflies who are designed to learn.
Well if want to think about a way of getting a taste of that kind of baby consciousness as adults, 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 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 to more full of consciousness and experience than all the months of being a walking, talking, 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 a baby? It’s like being love in Paris for the first time after you’ve had double-espressos. (Laughter) That’s a fantastic way to be, but it tend to leave you waking up crying at three o’clock in morning.
(Laughter)
Now it’s good to 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. And it makes sense that we a lot of effort into making babies think like adults do. if what we want is to be like those butterflies, to have open-mindedness, open learning, imagination, creativity, innovation, maybe least some of the time we should be getting the adults to start thinking more children.
(Applause)