What is going in this baby’s mind? If 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 has completely overturned that picture. So in some ways, we think that this baby’s is like the thinking of the most brilliant scientists.
Let me give you one example of this. One thing that this baby could be thinking about, that could be going in his mind, is trying to figure out what’s going on the mind of that other baby. After all, one of things that’s hardest for all of us to do is to figure what other people are thinking and feeling. And maybe hardest thing of all is to figure out that other people think and feel isn’t actually exactly like we think and feel. Anyone who’s followed politics can testify to how hard is for some people to get. We wanted to if babies and young children could understand this really profound thing about other people. Now the is: How 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 monologue about ponies and birthdays things like that. So how do we actually ask them the question?
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it turns out that the secret was broccoli. What we did — Betty Rapacholi, who was one my students, and I — was actually to give babies two bowls of food: one bowl of raw broccoli and bowl of delicious goldfish crackers. Now all of the babies, even in Berkley, the crackers and don’t like the raw broccoli. (Laughter) But then what Betty was to take a little 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 the broccoli go, “Mmmmm, broccoli. I tasted the broccoli. Mmmmm.” And then she would take a little bit of crackers, and she’d go, “Eww, yuck, crackers. I tasted crackers. Eww, yuck.” So she’d act as if what wanted was just the opposite of what the babies wanted. We did this with 15 18 month-old babies. And then she would simply put her 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 barely walking and talking, would give the crackers if she liked the crackers, but they would her the broccoli if she liked the broccoli. On other hand, 15 month-olds would stare at her for a long time she acted as if she liked the broccoli, like they couldn’t figure out. But then after they stared for a long time, would just give her the crackers, what they thought everybody must like. So there are two remarkable things about this. The first one is that 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, they felt that should actually do things to help other people get what wanted.
Even more remarkably though, the fact that 15 month-olds didn’t do this that these 18 month-olds had learned this deep, profound fact human nature in the three months from when they were 15 months old. So children both more and learn more than we ever would have thought. And this is just one of hundreds and of studies over the last 20 years that’s actually it.
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The question you might ask though is: Why do learn so much? And how is it possible for them to so much in such a short time? I mean, after all, you look at babies superficially, they seem pretty useless. And in 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 of why we spend so much time taking of useless babies, it turns out that there’s actually answer. If we look across many, many different species of animals, not us primates, but also including other mammals, birds, even marsupials like kangaroos wombats, it turns out that there’s a relationship between how long a childhood a species has and how their brains are compared to their bodies and how and flexible they are.
And sort of the posterbirds for idea are the birds up there. On one side is a New crow. And crows and other corvidae, ravens, rooks and so forth, are incredibly smart birds. They’re smart as chimpanzees in some respects. And this is a bird the cover of science who’s learned how to use a tool get food. On the other hand, we have our the domestic chicken. And chickens and ducks and geese turkeys are basically as dumb as dumps. So they’re very, very at pecking for grain, and they’re not much good at doing else. Well it turns out that the babies, the Caledonian crow babies, are fledglings. They depend on their to drop worms in their little open mouths for as as two years, which is a really long time in the of a bird. Whereas the chickens are actually mature within a couple of months. So childhood is reason why the crows end up on the cover of Science and the chickens end up in soup pot.
There’s something about that long childhood that to be connected to knowledge and learning. Well what of explanation could we have for this? Well some animals, the chicken, seem to be beautifully suited to doing just one thing very well. So they to be beautifully suited to pecking grain in one environment. creatures, like the crows, aren’t very good at doing in particular, but they’re extremely good at learning about laws different environments.
And of course, we human beings are way out on the end the distribution like the crows. We have bigger brains relative to our bodies by than any other animal. We’re smarter, we’re more flexible, we learn more, we survive in more different environments, we migrated to cover the world 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 popping those worms into those little open mouths.
All right, why would we see correlation? Well an idea is that that strategy, that learning strategy, an extremely powerful, great strategy for getting on in the world, but it has big disadvantage. And that one big disadvantage is that, you actually do 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 slingshot or maybe spear might work. Which would actually be better?” You to know all that before the mastodons actually show up. And the way the seems to have solved that problem is with a kind of division of labor. So idea is that we 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, 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 is that babies and young children are like the research and development of 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 take all those ideas that we learned when we children and actually put them to use. Another way of thinking about it is instead of thinking of and children as being like defective grownups, we should about them as being a different developmental stage of the species — kind of like caterpillars and butterflies — that they’re actually the brilliant butterflies who are flitting around garden and exploring, and we’re the caterpillars who are along our narrow, grownup, adult path.
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If this is true, if these babies are designed to — and this evolutionary story would say children are for learning, that’s they’re for — 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. And there’s been revolution in our understanding of machine learning recently. And all depends on the ideas of this guy, the Reverend Thomas Bayes, was a statistician and mathematician in the 18th century. And essentially what did was to provide a mathematical way using probability to characterize, describe, the way that scientists find out about the world. So what scientists 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 change that hypothesis. Then they test that new hypothesis and so on and so forth. And what showed was a mathematical way that you could do that. And mathematics is at the core of the best machine learning programs that have now. And some 10 years ago, I suggested babies might be doing 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 actually making complicated calculations with conditional probabilities that they’re revising to figure out how world works. All right, now that might seem like an even order to actually demonstrate. Because after all, if you ask even grownups about statistics, they extremely stupid. How could it be that children are doing statistics?
So to test this used a machine that we have called the Blicket Detector. This is box that lights up and plays music when you some things on it and not others. And using this very simple machine, lab and others have done dozens of studies showing just how good are at learning about the world. Let me mention one that we did with Tumar Kushner, my student. I showed you this detector, you would be likely think to begin with that 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 wave a block over the top of the detector, something wouldn’t ever think of to begin with, the detector will actually activate out of three times. Whereas, if you do the thing, put the block on the detector, it will only activate two out of six times. So the hypothesis actually has stronger evidence. It looks as if waving is a more effective strategy than the other strategy. So we just this; we gave four year-olds this pattern of evidence, and we just asked them to it go. And sure enough, the four year-olds used the to wave the object on top of the detector.
Now there are 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 that 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 world, that seems very unlikely to begin with. And studies we’ve just been doing in my lab, similar studies, we’ve show four year-olds are actually better at finding out an hypothesis than adults are when we give them exactly the same task. in these circumstances, the children are using statistics to find about the world, but after all, scientists also do experiments, and wanted to see if children are doing experiments. When children experiments we 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 experimental research program. Here’s one from Cristine Legare’s lab. What Cristine was use our Blicket Detectors. And what she did show children that yellow ones made it go and red ones didn’t, and then she showed them anomaly. And what you’ll see is that this little boy will go five hypotheses in the space of two minutes.
(Video) Boy: How about this? Same as other side.
Alison Gopnik: Okay, so his first hypothesis has just falsified.
(Laughter)
Boy: This one 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 expression of despair.
(Laughter)
Boy: Oh, it’s because this needs to be like this, this needs to be 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, to try putting it out onto other location. Not working either.
Boy: Oh, because the light goes only here, not here. Oh, the bottom of this box has in 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 make it up and two on this one to make it light up.
AG: Okay,there’s fifth hypothesis.
Now that is a particularly — that is particularly adorable and articulate little boy, but what Cristine discovered is this is quite typical. If you look at the way children play, when ask them to explain something, what they really do is do a series of experiments. is actually 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 test five hypotheses in two minutes? Well, if you back to those psychologists and philosophers, a lot of have said that babies and young children were barely if they were conscious at all. And I think just the is 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 of 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 bright and vivid, everything else sort of goes dark. And we even know about the way the brain does this.
So what happens when we pay is that the prefrontal cortex, the sort of executive part of brains, sends a signal that makes a little part of our brain more flexible, more plastic, better at learning, and shuts down in all the rest of our brains. So we a very focused, purpose-driven kind of attention. If we at babies and young children, we see something very different. I think babies young children seem to have more of a lantern of consciousness than a spotlight consciousness. So babies and young children are very bad at narrowing to just one thing. But they’re very good at in lots of information from 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, and the inhibitory parts haven’t come on yet. when we say that babies and young children are at paying attention, what we really mean is that they’re bad not paying attention. So they’re bad at getting rid all the interesting things that could tell them something just looking at the thing that’s important. That’s the kind attention, the kind of consciousness, that we might expect those butterflies who are designed to learn.
Well if we want to about a way of getting a taste of that kind of baby as adults, I think the best thing is think about where we’re put in a new situation that we’ve never been in before — when fall in love with someone new, or when we’re in a new city for first time. And what happens then is not that our contracts, it expands, so that those three days in Paris seem be more full of consciousness and experience than all the of being a walking, talking, faculty meeting-attending zombie back home. by the way, that coffee, that wonderful coffee you’ve been drinking downstairs, actually the effect 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 fantastic way to be, but it does tend to you waking 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 about how wonderful babies are. It’s good be a grownup. We can do things like tie shoelaces and cross the street by ourselves. And it sense that we put a lot of effort into making babies think like do. But if what we want is to be like butterflies, to have open-mindedness, open learning, imagination, creativity, innovation, at least some of the time we should be the adults to start thinking more like children.
(Applause)