What is on in this baby’s mind? If you’d asked people this 30 ago, most 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 and effect. In last 20 years, developmental science has completely overturned that picture. in some ways, we think that this baby’s thinking is like thinking of the most brilliant scientists.
Let me give you one example of this. One thing that this baby be thinking about, that could be going on in mind, is trying to figure out what’s going on in mind of that other baby. After all, one of the things that’s for all of us to do is to figure out what other people thinking and feeling. And maybe the hardest thing of all is to out that what other people think and feel isn’t exactly like what we think and feel. Anyone who’s followed politics can to how hard that is for some people to get. We 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 three year-old to tell you what he thinks, what you’ll get is a beautiful stream of consciousness monologue ponies and birthdays and things like that. So how we actually ask them 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, I — was actually to give the babies two of food: one bowl of raw broccoli and one bowl of delicious goldfish crackers. all of the babies, even in Berkley, like the crackers don’t like the raw broccoli. (Laughter) But then what Betty did 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, she acted as she liked the crackers and didn’t like the broccoli — just like a baby and other sane person. But half the time, what she 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 the crackers. Eww, yuck.” So she’d act if what she wanted was just the opposite of what the babies wanted. We this with 15 and 18 month-old babies. And then she would simply put her hand and say, “Can you give me some?”
So the is: What would the baby give her, what they or what she liked? And the remarkable thing was 18 month-old babies, just barely walking and talking, would give her the crackers if she liked the crackers, they would give her the broccoli if she liked the broccoli. On the other hand, 15 month-olds stare at her for a long time if she acted as she liked the broccoli, like they couldn’t figure this out. But then after they stared for long time, they would just give her the crackers, what they thought must 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 the same thing. And what’s more, they that they should actually do things to help other get what they wanted.
Even more remarkably though, the that 15 month-olds didn’t do this suggests that these 18 month-olds had learned this deep, profound fact human nature in the three months from when they 15 months old. So children both know more and learn more than we ever have thought. And this is just one of hundreds and of studies over the last 20 years that’s actually demonstrated it.
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question you might ask though is: Why do children learn much? And how is it possible for them to learn so much such a short time? I mean, after all, if you look at superficially, they seem pretty useless. And actually in many ways, they’re than useless, because we have to 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 so much time taking care of useless babies, it turns out that there’s an answer. If we look across many, many different of animals, not just us primates, but also including other mammals, birds, even marsupials like and wombats, it turns out that there’s a relationship between how long a 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 Caledonian crow. And crows other corvidae, ravens, rooks and so forth, are incredibly smart birds. They’re smart as chimpanzees in some respects. And this is bird on the cover of science who’s learned how to use a tool get food. On the other hand, we have our friend the domestic chicken. And chickens and and geese and turkeys are basically as dumb as dumps. So they’re very, very at pecking for grain, and they’re not much good at doing anything else. Well it turns that the babies, the New Caledonian crow babies, are fledglings. They depend on their to drop worms in their little open mouths for as long two years, which is a really long time in life of a bird. Whereas the chickens are actually mature within a of months. So childhood is the reason why the crows end up the cover of Science and the 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 could we have for this? Well some animals, like chicken, seem to be beautifully suited to doing just one thing very well. they seem to be beautifully suited to pecking grain in 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 beings way out on the end of the distribution like the crows. We have bigger brains to our bodies by far than any other animal. We’re smarter, we’re flexible, we can learn more, we survive in more environments, we migrated to cover the world and even go to outer space. And our babies 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 into little open mouths.
All right, why would we see this correlation? Well idea is that that strategy, that learning strategy, is an extremely powerful, strategy for getting on in the world, but it one big disadvantage. And that one big disadvantage is that, until you actually do all learning, you’re going to be helpless. So you don’t to have the mastodon charging at you and be saying yourself, “A slingshot or maybe a spear might work. Which would be better?” You want to know all that before the mastodons show up. And the way the evolutions seems to have solved that problem is with 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 do 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 it is that babies and young children are like the and development division of 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 to take all those ideas that we learned when we were children and put them to use. Another way of thinking about is instead of thinking of babies and children as like defective grownups, we should think about them as being a different developmental stage of same species — kind of like caterpillars and butterflies — except that they’re 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, these babies are designed to learn — and this story would say children are for learning, that’s what they’re for — we might that they would have really powerful learning mechanisms. And fact, the baby’s brain seems to be the most powerful computer on the planet. But real computers are actually getting to be a better. And there’s been a revolution in our understanding of machine learning recently. it 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 provide a mathematical using probability theory to characterize, describe, the way that scientists out about the world. So what scientists do is they have a hypothesis that they might be likely to start with. They go out and test against the evidence. The evidence makes them change that hypothesis. they test that new hypothesis and so on and forth. And what Bayes showed was a mathematical way you could do that. And that mathematics is at core of the best machine learning programs that we 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 those beautiful brown eyes, I think it actually looks something like this. This Reverend Bayes’s notebook. So I think those babies are actually making calculations with conditional probabilities that they’re revising to figure out how the works. All right, now that might seem like an even taller order actually demonstrate. Because after all, if you ask even grownups about statistics, they look stupid. How could it be that children are doing statistics?
So test this we used a machine that we have called Blicket Detector. This is a box that lights up and plays music when you put some things on and not others. And using this very simple machine, my and others have done dozens of studies showing just how good babies are learning about the world. Let me 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 to the detector go would be to put a block on top of the detector. But actually, detector 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 of to begin with, the will actually activate two out of three times. Whereas, if do the likely thing, put the block on the detector, will only activate two out of six times. So the unlikely actually has stronger evidence. It looks as if the waving a more effective strategy than the other strategy. So we did this; we gave four 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 about this. The one is, again, remember, these 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 to an idea, get to a hypothesis about the world, that seems very to begin with. And in studies we’ve just been doing my lab, similar studies, we’ve show that four year-olds actually better at finding out an unlikely hypothesis than adults are when we give them exactly same task. So in these circumstances, the children are using to find out about the world, but after all, scientists also experiments, and we wanted to see if children are doing experiments. When do experiments we call it “getting into everything” or else “playing.”
And there’s been a of interesting studies recently that have shown this playing around is really a kind experimental research program. Here’s one from Cristine Legare’s lab. What Cristine did use our Blicket Detectors. And what she did was show children that ones made it go and red ones didn’t, and she showed them an anomaly. And what you’ll see is that this boy will go through five hypotheses in the space two minutes.
(Video) Boy: How about this? Same as the other side.
Alison Gopnik: Okay, so first hypothesis has just been falsified.
(Laughter)
Boy: This one up, and this one nothing.
AG: Okay, he’s got experimental notebook out.
Boy: What’s making this light up. (Laughter) I don’t know.
AG: Every scientist recognize that expression of 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 is his next idea. He told the experimenter to do this, to try putting it onto the other location. Not working either.
Boy: Oh, because the light goes to 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 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 a particularly adorable and articulate little boy, what Cristine discovered is this is actually quite typical. If you look at the way play, when you ask them to explain something, what they really 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 these brilliant butterflies who can test five hypotheses in two minutes? Well, if you go to those psychologists and philosophers, a lot of them have said that babies and young children barely conscious if they were conscious at all. And I think just the opposite true. I think babies and children are actually more conscious than we are adults. Now here’s what 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 to it. Our consciousness of that thing that we’re attending to becomes extremely bright vivid, and everything else sort of goes dark. And even know something about the way the brain does this.
So what happens when we attention is that the prefrontal cortex, the sort of executive part of our brains, sends a signal makes a little part of our brain much more flexible, plastic, better at learning, and shuts down activity in all the rest of our brains. So we a very focused, purpose-driven kind of attention. If we look babies and young children, we see something very different. think babies and young children seem to have more of a lantern of than a spotlight of consciousness. So babies and young children are very bad at narrowing down to one thing. But they’re very good at taking in lots of information from lots of sources at once. And if you actually look in their brains, you see that they’re with these neurotransmitters that are really good at inducing learning and plasticity, and the inhibitory parts haven’t come yet. So when we say that babies and young children bad at paying attention, what we really mean is they’re bad at not paying attention. So they’re bad getting rid of all the interesting things that could them something 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 a taste of that kind of baby consciousness as adults, I think best thing is think about cases where we’re put in a new situation that we’ve never in before — when we fall in love with someone new, or when we’re in new city for the first time. And what happens then is not that our consciousness contracts, expands, so that those three days in Paris seem to be more of consciousness and experience than all the months of being walking, talking, faculty meeting-attending zombie back home. And by way, that coffee, that wonderful coffee you’ve been drinking downstairs, mimics 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 about how wonderful babies are. It’s good to be grownup. We can do things like tie our shoelaces cross the street by ourselves. And it makes sense that we put a of effort into making babies think like adults do. But what we want is to be like those 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)