What is going on this baby’s mind? If you’d asked people this 30 years ago, people, including psychologists, would have said that this baby was irrational, illogical, egocentric — that couldn’t take the perspective of another person or understand cause effect. In the last 20 years, developmental science has completely that picture. So in some ways, we think that this baby’s thinking like the thinking of the most brilliant scientists.
Let give you just one example of this. One thing that baby could be thinking about, that could be going on in his mind, is to figure out what’s going on in the mind that other baby. After all, one of the things that’s hardest for of us to do is to figure out what other people thinking and feeling. And maybe the hardest thing of all is to figure out what other people think and feel isn’t actually exactly like what 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 them? Babies, after all, can’t talk, and if you ask a three year-old to tell what he thinks, what you’ll get is a beautiful stream consciousness monologue about ponies and birthdays and things like that. how do we actually ask them the question?
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Well it turns out that the was broccoli. What we did — Betty Rapacholi, who was one of my students, I — was actually to give the babies two of food: one bowl of raw broccoli and one bowl delicious goldfish crackers. Now all of the babies, even in Berkley, like the crackers and don’t like raw broccoli. (Laughter) But then what Betty did was to take little taste of food from each bowl. And she would act as she liked it or she didn’t. So half the 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 little of the broccoli and go, “Mmmmm, broccoli. I tasted 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 what she wanted was just opposite of what the babies wanted. We did this 15 and 18 month-old babies. And then she would simply her hand out and say, “Can you give me some?”
So the question is: What would the baby give her, they liked or what she liked? And the remarkable thing was 18 month-old babies, just barely walking and talking, would give her crackers if she liked the crackers, but they would give her the broccoli if she 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, they couldn’t figure this out. But then after they stared for a time, they would just give her the crackers, what they thought must like. So there are two really remarkable things about this. first one is that these little 18 month-old babies have already discovered this really profound fact about nature, that we don’t always want the same thing. And what’s more, 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 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 would have thought. And this is 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 learn so much in such a short time? I mean, after all, if you at babies superficially, they seem pretty useless. And actually in many ways, they’re worse useless, because we have to put so much time and energy into keeping them alive. But if we turn to evolution for answer to this puzzle of why we spend so much time taking care of babies, it turns out that there’s actually an answer. If we look across many, many different species animals, not just us primates, but also including other mammals, birds, even marsupials like kangaroos and wombats, turns out that there’s a relationship between how long a childhood species has and how big their brains are compared to their bodies and how smart and flexible are.
And sort of the posterbirds for this idea are the birds there. On one side is a New Caledonian crow. And and other corvidae, ravens, rooks and so forth, are smart birds. They’re as smart as chimpanzees in some respects. And this is a bird on the of science who’s learned how to use a tool to get food. On the other hand, we have friend the domestic chicken. And chickens and ducks and geese turkeys are basically as dumb as dumps. So 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 as years, which is a really 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 end up on the cover of Science and the end up 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 have for this? Well animals, like the chicken, seem to be beautifully suited to doing just one thing well. So they seem to be beautifully suited to pecking grain in one environment. Other creatures, like 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 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, survive in more different environments, we migrated to cover world 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) And at least until they’re 23, we’re still popping worms into those little open mouths.
All right, why would we see this correlation? Well idea is that that strategy, that learning strategy, is an extremely powerful, great for getting on in the world, but it has one disadvantage. And that one big disadvantage is that, until you actually do all learning, you’re going to be helpless. So you don’t want to have the mastodon charging at you and saying to yourself, “A slingshot or maybe a spear work. Which would actually be better?” You want to all that before the mastodons actually show up. And the way the evolutions seems to have solved that is with a kind of division of labor. So idea is that we have this early period when we’re protected. We don’t have to do anything. All we have do is learn. And then as adults, we can all those things that we learned when we were babies and children and actually them to work to do things out there in world.
So one way of thinking about it is that babies young children are like the research and development division the human species. So they’re the protected blue sky guys who just have to out and learn and have good ideas, and we’re production and marketing. We have take all those ideas that we learned when we were children and actually them to use. Another way of thinking about it is instead of thinking of babies and as being like defective grownups, we should think about them as being a different developmental stage the same species — kind of like caterpillars and butterflies — that they’re actually the brilliant butterflies who are flitting around the garden and exploring, and we’re the caterpillars are inching along our narrow, grownup, adult path.
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If is 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 really powerful learning mechanisms. And in fact, the baby’s brain seems to be the most learning computer on the planet. But real computers are getting to be a lot better. And there’s been revolution in our understanding of machine learning recently. And all depends on the ideas of this guy, the Thomas Bayes, who was a statistician and mathematician in 18th century. And essentially what Bayes did was to a mathematical way using probability theory to characterize, describe, the way that scientists find out about the world. what scientists do is they have a hypothesis that they think might be likely to with. They go out and test it against the evidence. evidence makes them change that hypothesis. Then they test that new hypothesis so on and so forth. And what Bayes showed a mathematical way that you could do that. And 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 same thing.
So if want to know what’s going on underneath those beautiful brown eyes, I think actually looks something like this. This is Reverend Bayes’s notebook. So I think babies are actually making complicated calculations with conditional probabilities that they’re revising to out how the world works. All right, now that seem like an even taller order to actually demonstrate. Because after all, if ask even grownups about statistics, they look extremely stupid. How it be that children are doing statistics?
So to test this used a machine that we have called the Blicket Detector. This is a box that lights up plays music when you put some things on it and not others. And using this very machine, my lab and others have done dozens of studies showing how good babies are at learning about the world. Let me just one that we did with Tumar Kushner, my student. If I showed this detector, you would be likely to think to begin with the way to make the detector go would be to put block on top of the detector. But actually, this works in a bit of a strange way. Because if you wave block over the top of the detector, something you wouldn’t ever think to begin with, the detector will actually 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 has stronger evidence. It looks as if the waving a more effective strategy than the other strategy. So we did just this; we gave 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 wave object on top of the detector.
Now there are two things that are really interesting this. The first one is, again, remember, these are four year-olds. They’re just learning how count. But unconsciously, they’re doing these quite complicated 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 world, that seems very unlikely to begin with. And in studies we’ve just doing in my lab, similar studies, we’ve show that year-olds are actually better at finding out an unlikely hypothesis than are when we give them exactly the same task. So in these circumstances, 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 children do experiments call 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 from Legare’s lab. What Cristine did was use our Blicket Detectors. what she did was show children that yellow ones it go and red ones didn’t, and then she them an anomaly. And what you’ll see is that this little boy go through five hypotheses in the space of two minutes.
(Video) Boy: How about this? Same the other side.
Alison Gopnik: Okay, so his first hypothesis has just been falsified.
(Laughter)
Boy: This lighted up, and 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 will recognize that expression 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 this is his next idea. He told experimenter to do this, to try putting it out the other location. Not working either.
Boy: Oh, because the goes only to here, not here. Oh, the bottom of this box has electricity here, but this doesn’t have electricity.
AG: Okay, that’s a fourth hypothesis.
Boy: It’s lighting up. when you put four. So you put four on this one make it light up and two on this one to it light up.
AG: Okay,there’s his fifth hypothesis.
Now that is a — that is a particularly adorable and articulate little boy, but Cristine discovered is this is actually quite typical. If you look at the children play, when you ask them to explain something, what really do is do a series of experiments. This is 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 psychologists and philosophers, a lot of them have said that babies and young were barely conscious if they were conscious at all. I think just the opposite is true. I think babies children 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 attention it. Our consciousness of that thing that we’re attending to becomes bright and vivid, and everything else sort of goes dark. And we even something about the way the brain does this.
So what happens when we attention is that the prefrontal cortex, the sort of executive of 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 our brains. we have a very focused, purpose-driven kind of attention. If we look at and young children, we see something very different. I think babies young children seem to have more of a lantern of consciousness a 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 of information from lots of different sources at once. And if you look in their brains, you see that they’re flooded with these neurotransmitters are really good at inducing learning and plasticity, and inhibitory parts haven’t come on yet. So when we say babies and young children are bad at paying attention, what we really mean is that they’re at not paying attention. So they’re bad at getting rid of the interesting things that could tell them 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 to think about a way of getting a taste that kind of baby consciousness as adults, I think the best thing think about cases where we’re put in a new situation we’ve never been in before — when we fall in love with someone new, or we’re in a new city for the first time. what happens then is not that our consciousness contracts, 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, faculty meeting-attending back home. And by the way, that coffee, that wonderful coffee you’ve been drinking downstairs, mimics the effect of those baby neurotransmitters. So what’s it 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 way to be, but it does tend to leave you up crying at three o’clock in the morning.
(Laughter)
Now it’s to be a grownup. I don’t want to say too much how wonderful babies are. It’s good to be a grownup. We do things like tie our shoelaces and cross the by ourselves. And it makes sense that we put a lot of into making babies think like adults do. But if what we want is to be like butterflies, to have open-mindedness, open learning, imagination, creativity, innovation, maybe at some of the time we should be getting the to start thinking more like children.
(Applause)