What going on in 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 he couldn’t take perspective of another person or understand cause and effect. the last 20 years, developmental science has completely overturned that picture. So in some ways, think that this baby’s thinking is like the thinking of the brilliant scientists.
Let me 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 of that other baby. After all, one of things that’s hardest for all of us to do is to out what other people are thinking and feeling. And maybe hardest thing of all is to figure out that what other think and feel isn’t actually exactly like what we think feel. Anyone who’s followed politics can testify to how hard is for some people to get. We wanted to know babies and young children could understand this really profound thing about other people. Now the question is: could we ask 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 of consciousness about ponies and birthdays and things like that. So how do we actually ask the question?
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Well it turns out that the secret was broccoli. What did — Betty Rapacholi, who was one of my students, and I — actually to give the babies two bowls of food: bowl of raw broccoli 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 take a little taste of food from each bowl. And would act as if she liked it or she didn’t. So half the time, she acted as if liked the crackers and didn’t like the broccoli — like a baby and any 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 little bit of the crackers, and she’d go, “Eww, yuck, crackers. I tasted the crackers. Eww, yuck.” she’d act as if what she wanted was just opposite of what the babies wanted. We did this with 15 18 month-old babies. And then she would simply put hand out and say, “Can you give me some?”
So the is: What would the baby give her, what they liked or she liked? And the remarkable thing was that 18 month-old babies, just barely and talking, would give her the crackers if she liked the crackers, but they give her the broccoli if she liked the broccoli. On other 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 after they stared for a long time, they would just give her crackers, what they thought everybody must like. So there are two really remarkable things about this. first one is that these little 18 month-old babies already discovered this really profound fact about human nature, that we don’t always the same thing. And what’s more, they felt that should actually do things to help other people get they 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 children both know and learn more than we ever would have thought. And this is just one hundreds and hundreds of studies over the last 20 that’s actually demonstrated it.
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The question you might ask though is: Why do children learn 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. 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 turn evolution for an answer to this puzzle of why we spend so much taking care of useless babies, it turns out that there’s an answer. If we look across many, many different species of animals, not just us primates, but including other mammals, birds, even marsupials like kangaroos and wombats, it turns out that there’s a relationship between how a childhood a species has and how big their are compared to their bodies and how smart and they are.
And sort of the posterbirds for this idea are birds up there. On one side is a New Caledonian crow. And crows and other corvidae, ravens, rooks so forth, are incredibly smart birds. They’re as smart chimpanzees in some respects. And this is a bird on cover of science who’s learned how to use a tool to get food. On the hand, we have our friend the domestic chicken. And chickens and ducks and geese and turkeys basically as dumb as dumps. So they’re very, very good at pecking for grain, they’re not much good at doing anything else. Well turns out that the babies, the New Caledonian crow babies, are fledglings. They depend on their moms drop worms in their little open mouths for as long as two years, which is really long time in the life of a bird. Whereas the chickens are mature within a couple of months. So childhood is the why the crows end up on the cover of Science and chickens end up in the soup pot.
There’s something that long childhood that seems to be connected to knowledge and learning. Well what kind of explanation could have for this? Well some animals, like the chicken, seem to be 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 course, we human beings are way out on the end the distribution like the crows. We have bigger brains relative to bodies by far than any other animal. We’re smarter, we’re more flexible, we learn more, we survive in more different environments, we migrated to the world and even go to outer space. And our babies and children dependent on us for much longer than the babies of any other species. My son is 23. (Laughter) at least until they’re 23, we’re still popping those worms those little open mouths.
All right, why would we see this correlation? an idea is that that strategy, that learning strategy, is an extremely powerful, great strategy for getting on the world, but it has one big disadvantage. And that one big disadvantage is that, until you actually all that learning, you’re going to be helpless. So you don’t want to have the charging at you and be saying to yourself, “A or maybe a spear might work. Which would actually be better?” You want to know all that before mastodons actually show up. And the way the evolutions to have solved that problem is with a kind division of labor. So the idea is that we have this period when we’re completely protected. We don’t have to do anything. All we to do is learn. And then as adults, we can take all those that we learned when we were babies and children and actually put them to work do things out there in the 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 who just have to go out and learn and good ideas, and we’re production and marketing. We have to take all ideas that we learned when we were children and actually put them to use. Another of thinking about it is instead of thinking of babies and 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 brilliant butterflies who are around the garden and exploring, and we’re the caterpillars who are inching along narrow, grownup, adult path.
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If this is true, if these babies designed to learn — and this evolutionary story would say are for 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 the most powerful learning computer on the planet. But real computers are actually getting be a lot better. And there’s been a revolution in understanding of machine learning recently. And it all depends on the of this guy, the Reverend Thomas Bayes, who was statistician and mathematician in the 18th century. And essentially what Bayes did was provide a mathematical way using probability theory 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 likely start with. They go out and test it against the evidence. The evidence them change 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 machine learning programs that we have now. And some 10 years ago, I 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 they’re revising to figure out how the world works. All right, now might seem like an even taller order to actually demonstrate. Because after all, if you ask even grownups statistics, they look extremely stupid. How could it be children are doing statistics?
So to test this we used a machine that we called the Blicket Detector. This is a box that lights up and plays when you put some things on it and not others. And using this simple machine, my lab and others have done dozens of studies showing just good babies are at learning about the world. Let mention just one that we did with Tumar Kushner, student. If I showed you this detector, you would likely to think to begin with that the way 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 you a block over the top of the detector, something wouldn’t ever think of to begin with, the detector will actually two out of three times. Whereas, if you do the likely thing, put block on the detector, it will only activate two out of times. So the unlikely hypothesis actually has stronger evidence. It looks as if waving is a 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 make it go. And sure enough, four year-olds used the evidence to wave the object 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 learning how to count. But unconsciously, they’re doing these quite complicated calculations that will give a conditional probability measure. And the other interesting thing is that they’re using evidence to get to an idea, get to a about the world, that seems very unlikely to begin with. in studies we’ve just been doing in my lab, similar studies, we’ve show that four year-olds are actually at finding out an unlikely hypothesis than adults are we give them exactly the same task. So in these circumstances, the children are using statistics find out about the world, but after all, scientists also do experiments, and we wanted to if children are doing experiments. When children do experiments we call it “getting into everything” or “playing.”
And there’s been a bunch of interesting studies that have shown this playing around is really a kind experimental research program. Here’s one from Cristine Legare’s lab. What Cristine did was use our Blicket Detectors. And she did was show children that yellow ones made go and red ones didn’t, and then she showed them an anomaly. what you’ll see is that this little boy will go through five 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 one nothing.
AG: Okay, he’s got his experimental notebook out.
Boy: What’s 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 be like this.
AG: Okay, hypothesis two.
Boy: That’s why. Oh.
(Laughter)
AG: Now is 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 goes only 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. when you put four. So you put four on this one make it light up and two on this one to make it light up.
AG: Okay,there’s his 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 at the way children play, when you ask them explain something, what they really do is do a series of experiments. This is actually pretty typical four year-olds.
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Well, what’s it like to this kind of creature? What’s it like to be one of these brilliant butterflies can test five hypotheses in two minutes? Well, if you go to those psychologists and philosophers, a lot of them have that babies and young children were barely conscious if they were conscious at all. I think just the opposite is true. I think babies and children are more conscious than 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 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 the brain does this.
So what when we pay attention is that the prefrontal cortex, the sort of part of our brains, sends a signal that makes a part of our brain much more flexible, more plastic, better at learning, and down activity in all the rest of our brains. So we a very focused, purpose-driven kind of attention. If we look at babies young children, we see something very different. I think babies and children seem to have more of a lantern of than 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 lots of information lots of different sources at once. And if you look in their brains, you see that they’re flooded with neurotransmitters that are really good at inducing learning and plasticity, the inhibitory parts haven’t come on yet. So when we say that babies 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 things could tell them something and just looking at the that’s important. That’s the kind of attention, the kind consciousness, that we might expect from those butterflies who are designed learn.
Well if we want to think about a 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 that we’ve been in before — when we fall in love someone new, or when we’re in a new city for the first time. And what happens then not that our consciousness contracts, it expands, so that those three days in Paris seem to be more 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, actually mimics effect of those baby neurotransmitters. So what’s it like to a 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 does tend leave you waking up crying at three o’clock in the morning.
(Laughter)
Now it’s good to be grownup. I don’t want to say too much about how wonderful babies are. It’s good to be grownup. We can do things like tie our shoelaces and cross street by ourselves. And it makes sense that we put 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)