What is on in this baby’s mind? If you’d asked people 30 years ago, most people, including psychologists, would have said that this was irrational, illogical, egocentric — that he couldn’t take the perspective of person or understand cause and effect. In the last 20 years, science has completely overturned that picture. So in some ways, we that this baby’s thinking is like the thinking of the most brilliant scientists.
Let me give just one example of this. One thing that this baby could be thinking about, that could going on in his mind, is trying to figure out what’s going on the mind of that other baby. After all, one of the things that’s hardest for all us to do is to figure out what other are thinking and feeling. And maybe the hardest thing of all to figure out 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 hard that is for some people get. We wanted to know if babies and young children could understand this really profound about other people. Now the question is: How could we ask them? Babies, all, can’t talk, and if you ask a three year-old to tell you what thinks, what you’ll get is a beautiful stream of consciousness 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 — Betty Rapacholi, who one of my students, and I — was actually to give the babies two bowls food: one bowl of raw broccoli and one bowl of goldfish crackers. Now all of the babies, even in Berkley, like crackers and don’t like the raw broccoli. (Laughter) But then what Betty did was take a little taste of food from each bowl. And she would as if she liked it or she didn’t. So half the time, she acted as if she liked crackers and didn’t like the broccoli — just like a baby and other sane person. But half the time, what she do is take a little bit of the broccoli and go, “Mmmmm, broccoli. tasted the broccoli. Mmmmm.” And then she would take a little of the 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 babies wanted. did this with 15 and 18 month-old babies. And then she would simply her hand out and say, “Can you give me some?”
So question is: What would the baby give her, what they liked what she liked? And the remarkable thing was that 18 month-old babies, just walking and talking, would give her the crackers if liked the crackers, but they would give her the broccoli if she liked the broccoli. On the hand, 15 month-olds would stare at her for a long time if she as if she liked the broccoli, like they couldn’t figure this out. But then after stared for a long time, they would just give the crackers, what they thought everybody must like. So there are two remarkable things about this. The first one is that these little 18 month-old babies have already discovered really 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 remarkably though, the fact that 15 month-olds didn’t do this suggests these 18 month-olds had learned this deep, profound fact about human nature in three months from when they were 15 months old. children both know more and learn more than we ever would have thought. And is just one of hundreds and hundreds of studies over last 20 years that’s actually demonstrated it.
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question you might ask though is: Why do children so much? And how is it possible for them learn so much in such a short time? I mean, all, if you look at babies superficially, they seem pretty useless. actually in many ways, they’re worse than useless, because we have to put much time and energy into just keeping them alive. But if turn to evolution for an answer to this puzzle of we spend so much time taking care of useless babies, it turns out that there’s an answer. If we look across many, many different of animals, not just us primates, but also including 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 flexible are.
And sort of the posterbirds for this idea are the birds up there. On one 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. And 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 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 turns out 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 as two years, which a really long time in the life of a bird. Whereas the chickens are actually mature a couple of months. So childhood is the reason why crows end up on the cover of Science and the end up in the soup pot.
There’s something about that long childhood seems to be connected to knowledge and learning. Well kind of explanation could we have for this? Well some animals, like the chicken, to be beautifully suited to doing just one thing very well. So seem to be beautifully suited to pecking grain in one environment. Other creatures, the crows, aren’t very good at doing anything in particular, they’re extremely good at learning about laws of different environments.
And of course, we human are way out on the end of the distribution like the crows. have bigger brains relative to our bodies by far than other animal. We’re smarter, we’re more flexible, we can learn more, we survive more different environments, we migrated to cover the world even go to outer space. And our babies and children are dependent on us for longer than 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 is that that strategy, that learning strategy, is an extremely powerful, strategy for getting on in the world, but it has big disadvantage. And that one big disadvantage is that, until actually do all that learning, you’re going to be helpless. you don’t want to have the mastodon charging at you and be saying to yourself, “A slingshot or a spear might 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 that problem is with a kind of division of labor. the idea is that we have this early period when we’re protected. We don’t have to do anything. All we have to do is learn. And then adults, we can take all those things that we when we were babies and children and actually put them to work to do things out there in world.
So one way of thinking about it is that babies and children are like the research and development division of the species. So they’re the protected blue sky guys who just have go out and learn and have good ideas, and we’re production and marketing. We have take all those ideas that we learned when we children and actually put them to use. Another way of about it is instead of thinking of babies and as being like defective grownups, we should think about them as being a different developmental of the same species — kind of like caterpillars and butterflies — except they’re actually the brilliant butterflies who 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 this true, if these babies are designed to learn — this evolutionary story would say children are for learning, that’s what they’re — we might expect that they would have really learning mechanisms. And in fact, the baby’s brain seems to be the most powerful learning computer on planet. But real computers are actually getting to be a lot better. there’s been a revolution in our understanding of machine learning recently. And all depends on the ideas of this guy, the Reverend Thomas Bayes, who was a statistician mathematician in the 18th century. And essentially what Bayes did was to provide a mathematical way using probability to characterize, describe, the way that scientists find out the world. So what scientists do is they have a hypothesis that they think might be to start with. They go out and test it against the evidence. The evidence makes them that hypothesis. Then they test that new hypothesis and so on and so forth. what Bayes showed was a mathematical way that you do that. And that mathematics is at the core of the best learning programs that we have now. And some 10 ago, I suggested that babies might be doing the same thing.
So if you want to what’s going on underneath those beautiful brown eyes, I think actually looks something like this. This is Reverend Bayes’s notebook. So I those babies are actually making complicated calculations with conditional probabilities that they’re revising to figure out how the works. All right, now that might seem like an even taller order to actually demonstrate. after all, if you ask even grownups about statistics, they look extremely stupid. How could it be that are doing statistics?
So to test this we used a machine that we have called Blicket Detector. This is a box that lights up plays music when you put some things on it not others. And using this very simple machine, my and others have done dozens of studies showing just how good babies are learning about the world. Let me mention just one that 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 detector works in a of a strange way. Because if you wave a block over top of the detector, something you wouldn’t ever 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 has stronger evidence. It looks as if the waving is a more effective strategy the other strategy. So we did just this; we four year-olds this pattern of evidence, and we just asked them to it go. And sure enough, the four year-olds used the evidence to the object on top of the detector.
Now there are two that are really interesting 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 complicated calculations that will give them a conditional probability measure. the other interesting thing is that they’re using that evidence to get to idea, get to a hypothesis about the world, that seems unlikely to begin with. And in studies we’ve just been doing in lab, similar studies, we’ve show 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 find out about the world, but after all, also do experiments, and we wanted to see if children are doing experiments. When do experiments we call it “getting into everything” or else “playing.”
And there’s been a of interesting studies recently that have shown this playing around really a kind of experimental research program. Here’s one from Legare’s lab. What Cristine did was use our Blicket Detectors. what 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 go through five in the space of two minutes.
(Video) Boy: How about this? Same the other side.
Alison Gopnik: Okay, so his first 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 scientist 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 his idea. He told the experimenter to do this, to try it out onto the other location. Not working either.
Boy: Oh, because the light goes to 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. So you put on this one to make it light up and two on this to make it light up.
AG: Okay,there’s his fifth hypothesis.
Now that is a particularly — that is particularly adorable and articulate little boy, but what Cristine is this is actually quite typical. If you look the way children play, when you ask them to explain something, they really do is do a series of experiments. This 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 who can test five hypotheses in two minutes? Well, if you go to those psychologists and philosophers, a lot of them have said babies and young children were barely conscious if they conscious at all. And I think just the opposite true. I think babies and children are actually more conscious we 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 we that something’s relevant or important, we should pay attention it. Our consciousness of that thing that we’re attending to becomes extremely and vivid, and everything else sort of goes dark. And we even know something about the way the does this.
So what happens when we pay attention is 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 activity all the rest of our brains. So we have very focused, purpose-driven kind of attention. If we look babies and young children, we see something very different. I think and young children seem to have more of a lantern of consciousness than spotlight of consciousness. So babies and young children are very bad at narrowing to just one thing. But they’re very good at taking in lots of information from lots of different at once. And if you actually look in their brains, you see that they’re with these neurotransmitters that are really good at inducing learning plasticity, and the inhibitory parts haven’t come on yet. So when we say that babies and young are bad at paying attention, what we really mean is that they’re bad at paying attention. So they’re bad at getting rid of all the interesting things that could tell something and just looking at the thing that’s important. That’s the of attention, the kind of consciousness, that we might expect from those who are designed to learn.
Well if we want think about a way of getting a taste of that of baby consciousness as adults, I think the best thing is think about cases where we’re in a new situation that we’ve never been in — when we fall in love with someone new, or we’re in a new city for the first time. And what happens is not that our consciousness contracts, it expands, so that three days in Paris seem to be more full consciousness and experience than all the months of being walking, talking, faculty meeting-attending zombie back home. And by the way, that coffee, that 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 in love in for the first time after you’ve had three double-espressos. (Laughter) That’s a fantastic 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 grownup. We can do things like tie our shoelaces and the street by ourselves. And it makes sense that we put a of effort into making babies think like adults do. But if what want is to be like those butterflies, to have open-mindedness, learning, imagination, creativity, innovation, maybe at least some of the we should be getting the adults to start thinking like children.
(Applause)