What is going on in this baby’s mind? you’d asked people this 30 years ago, most people, psychologists, would have said that this baby was 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 completely 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 to figure out what’s going on in the mind of other baby. After all, one of the things that’s hardest all of us to do is to figure out what other people are 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 we think and feel. Anyone who’s politics can testify to how hard that is for some people to get. wanted to know if babies and young children could understand really profound thing 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 tell you what he thinks, what you’ll get is beautiful stream of consciousness monologue about ponies and birthdays and things that. So how do we actually ask them the question?
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Well it turns out that secret was broccoli. What we did — Betty Rapacholi, was one of my students, and I — was actually to the babies two bowls of food: one bowl of raw and one bowl of delicious goldfish crackers. Now all the babies, even in Berkley, like the crackers and don’t like raw broccoli. (Laughter) But then what Betty did was to take a taste of food from each bowl. And she would act as if liked it or she didn’t. So half the time, acted as if she liked the crackers and didn’t like broccoli — just like a baby and any other sane person. half the time, what she would do is take a little bit of broccoli and go, “Mmmmm, broccoli. I tasted the broccoli. Mmmmm.” And then would take a little bit 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 would simply her hand out and say, “Can you give me some?”
So the question is: would the baby give her, what they liked or what she liked? And remarkable thing was that 18 month-old babies, just barely walking and talking, would give her the crackers she liked the crackers, but they would give her broccoli if she liked the broccoli. On the other hand, 15 month-olds would at her for a long time if she acted as if liked the broccoli, like they couldn’t figure this out. But after they stared for a long time, they would just give her the crackers, what they thought everybody like. So there are two really remarkable things about this. The first one that these little 18 month-old babies have already discovered 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 what they wanted.
Even more remarkably though, the fact 15 month-olds didn’t do this suggests that these 18 month-olds 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. this is just one of hundreds and hundreds of studies over last 20 years that’s actually demonstrated it.
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The you might ask though is: Why do children learn so much? And how it possible for them to learn so much in such a short time? mean, after all, if you look at babies superficially, they seem pretty useless. And actually many ways, they’re worse than useless, because we have put so much time and energy into just keeping them alive. But we turn to evolution for an answer to this puzzle 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 species of animals, not just us primates, but also including other mammals, birds, marsupials like kangaroos and wombats, it turns out that there’s a relationship between how long childhood a species has and how big their brains are compared to their bodies and smart and flexible they are.
And sort of the posterbirds for this idea are the birds up there. one side is a New Caledonian crow. And crows other corvidae, ravens, rooks and so forth, are incredibly birds. They’re as smart as chimpanzees in some respects. And this is a bird on the cover science who’s learned how to use a tool to food. On the other hand, we have our friend the chicken. And chickens and ducks and geese and turkeys are as dumb as dumps. So they’re very, very good at pecking for grain, and they’re not good at doing anything else. Well it turns out that the babies, the New Caledonian babies, are fledglings. They depend on their moms to drop worms in their little mouths for as long as two years, which is a really long time in the life a bird. Whereas the chickens are actually mature within a couple of months. So childhood is the reason the crows end up on the cover of Science and the chickens up in the soup pot.
There’s something about that long childhood that seems to be connected to knowledge learning. Well what kind of explanation could we have this? Well some animals, like the chicken, seem to be beautifully suited doing just one thing very well. So they seem to be beautifully suited pecking grain in one environment. Other creatures, like the crows, aren’t very good doing anything in particular, but they’re extremely good at about laws of different environments.
And of course, we human are way out on the end of the distribution like crows. We have bigger brains relative to our bodies far than any other animal. We’re smarter, we’re more flexible, can learn more, we survive in more different environments, we to cover the world and even go to outer space. And babies and children are dependent on us for much than the babies of any other species. My son is 23. (Laughter) And at until they’re 23, we’re still popping those worms into those little open mouths.
All right, would we see this correlation? Well an idea is that that strategy, that strategy, is an extremely powerful, great strategy for getting on the world, but it has one big disadvantage. And 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 charging at you and be saying to yourself, “A slingshot or a spear might work. Which would actually be better?” want to know all that before the mastodons actually up. And the way the evolutions seems to have that problem is with a kind of division of labor. So the idea is that we this early period when we’re completely protected. We don’t have to do anything. All we have to 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 about it is that babies and young children are like research and 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 all those ideas that we learned when we were children and actually them to use. Another way of thinking about it instead of thinking of babies and children as being like defective grownups, we should think about them being a different developmental stage of the same species — kind of caterpillars and butterflies — except that they’re actually the butterflies who are flitting around the garden and exploring, we’re the caterpillars who are inching along our narrow, grownup, path.
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If this is true, if these babies designed to learn — and this evolutionary story would say children for learning, that’s what they’re for — we might that they would have really powerful learning mechanisms. And in fact, the baby’s brain seems to be most powerful learning computer on the planet. But real computers are getting to be a lot better. And there’s been a revolution in our understanding of machine recently. And it all depends on the ideas of this guy, the Reverend Thomas Bayes, who a statistician and mathematician in the 18th century. And essentially what Bayes did was to provide a way using probability theory to characterize, describe, the way that scientists find about the world. So what scientists do is they have a hypothesis that think might be likely to start with. They go out and test it against evidence. The evidence makes them change that hypothesis. Then they test that new hypothesis and on and so forth. And what Bayes showed was mathematical way that you could do that. And that mathematics is the core of the best machine learning programs that we have now. And 10 years ago, I suggested that babies might be the same thing.
So if you want to know what’s going on underneath beautiful brown eyes, I think it actually looks something like this. is Reverend Bayes’s notebook. So I think those babies are actually making complicated calculations with probabilities that they’re revising to figure out how the world works. All right, now that might seem an even taller order to actually demonstrate. Because after all, if 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 called the Blicket Detector. This is a box that lights up plays music when you put some things on it and others. And using this very simple machine, my lab and others have done dozens of studies just how good babies are at learning about the world. Let me mention just one that we did with Kushner, my student. If I showed you this detector, you would be likely to think to with that the way to make the detector go would be to put a block on top the detector. But actually, this detector works 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 begin with, the detector will actually activate two out of times. Whereas, if you do the likely thing, put block on the detector, it will only activate two out of six times. So the unlikely actually has stronger 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 pattern of evidence, and we just asked them to make it go. sure enough, the four year-olds used the evidence to the object on top of the detector.
Now there two things that are really interesting about this. The first is, again, remember, these are four year-olds. They’re just learning to count. But unconsciously, they’re doing these quite complicated calculations will give them a conditional probability measure. And the other interesting thing is they’re using that evidence to get to an idea, get a hypothesis about the world, that seems very unlikely to begin with. And in we’ve just been doing in my lab, similar studies, we’ve show that 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, also do experiments, and we wanted to see if are doing experiments. When children do experiments we call it “getting into everything” or “playing.”
And there’s been a bunch of interesting studies recently have shown this playing around is really a kind of experimental program. Here’s one from Cristine Legare’s lab. What Cristine 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 them an anomaly. And what you’ll see is that this boy will go through five hypotheses in the space of two minutes.
(Video) Boy: How about this? as the other side.
Alison Gopnik: Okay, so his first hypothesis has been falsified.
(Laughter)
Boy: This one lighted up, and this 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 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 try putting it out onto the other location. working either.
Boy: Oh, because the light goes only here, not here. Oh, the bottom of this box electricity in here, but this doesn’t have electricity.
AG: Okay, that’s a fourth hypothesis.
Boy: It’s up. So when you put four. So you put four on this one to it light up and two on this one to make it up.
AG: Okay,there’s his fifth hypothesis.
Now that is a particularly — that a particularly adorable and articulate little boy, but what discovered is this is actually quite typical. If you look the way children play, when you ask them to explain something, what really do is do a series of experiments. This is actually pretty typical of year-olds.
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Well, what’s it like to be kind of creature? What’s it like to be one of brilliant butterflies who can test five hypotheses in two minutes? Well, if you go back to those and philosophers, a lot of them have said that and young children were barely conscious if they were conscious at all. And I think the opposite is true. I think babies and children are more conscious than we are as adults. Now here’s we know about how adult consciousness works. And adults’ attention and look kind of like a spotlight. So what happens for adults we decide that something’s relevant or important, we should pay attention to it. Our consciousness of that that we’re attending to becomes extremely bright and vivid, and everything else of goes dark. And we even know something about the way brain does this.
So what happens when we pay attention is that prefrontal cortex, the sort of executive part of our brains, sends a signal that a little part of our brain much more flexible, more plastic, better at learning, and down activity in all the rest of our brains. So we have a focused, purpose-driven kind of attention. If we look at babies and young children, we something very different. I think babies and young children to have more of a lantern of consciousness than a of consciousness. So babies and young children are very bad at narrowing down to just thing. But they’re very good at taking in lots of information from lots of different sources at once. if you actually look in their brains, you see that they’re flooded with these neurotransmitters that are good at inducing learning and plasticity, and the inhibitory haven’t come on yet. So when we say that babies and children are bad at paying attention, what we really is that they’re bad at not paying attention. So they’re bad at getting rid of all the interesting things could tell them something and just looking at the thing that’s important. That’s kind of attention, the kind of consciousness, that we expect from those butterflies who are designed to learn.
Well we want to think about a way of getting a taste of kind of baby consciousness as adults, I think the best is think about cases where we’re put in a new situation that we’ve never been before — when we fall in love with someone new, or when we’re in a new city for the time. And what happens then is not that our contracts, it expands, so that those three days in Paris seem to be more of consciousness and experience than all the months of a walking, talking, faculty meeting-attending zombie back home. And by the way, coffee, that wonderful coffee you’ve been drinking downstairs, actually mimics the of those baby neurotransmitters. So what’s it like to a baby? It’s like being in love in Paris 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 to be a grownup. I don’t want to say much about 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 effort making babies think like adults do. But if what we is to be like those butterflies, to have open-mindedness, learning, imagination, creativity, innovation, maybe at least some of the time we be getting the adults to start thinking more like children.
(Applause)