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