What is going on 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 the perspective of another person or understand cause and effect. the last 20 years, developmental science has completely overturned that picture. in some ways, we think that this baby’s thinking is like the thinking of the most scientists.
Let me give you just one example of this. One that this baby could be thinking about, that could be going on in mind, is trying to figure out what’s going on in the mind of that baby. After all, one of the things that’s hardest all of us to do is to figure out what other are thinking and feeling. And maybe the hardest thing of all to figure out that what other people think and feel isn’t actually like what we think and feel. Anyone who’s followed politics can testify to how hard that for some people to get. We wanted to know if babies and children could understand this really profound thing about other people. Now question is: How could we ask them? Babies, after 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 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 — Rapacholi, who was one of my students, and I — was actually to give the babies two of food: one bowl of raw broccoli and one bowl delicious goldfish crackers. Now all of the babies, even in Berkley, like the crackers and don’t like the broccoli. (Laughter) But then what Betty did was to take a little taste of food each bowl. And she would act as if she it or she didn’t. So half the time, she acted as if liked the crackers and didn’t like the broccoli — just like a baby any other sane person. But half the time, what she would do take a little bit of the broccoli and go, “Mmmmm, broccoli. I the broccoli. Mmmmm.” And then she would take a little bit 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 wanted. We 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 the remarkable was that 18 month-old babies, just barely walking and talking, give her the crackers if she liked the crackers, they would give her the broccoli if she liked broccoli. On the other hand, 15 month-olds would stare at her for a time if she acted as if she liked the broccoli, they couldn’t figure this out. But then after they for a long time, they would just give her crackers, what they thought everybody must like. So there are two remarkable things about this. The first one is that these little 18 month-old babies already discovered this really profound fact about human nature, we don’t always want the same thing. And what’s more, they felt that they should do things to help other people get what they wanted.
Even remarkably though, the fact that 15 month-olds didn’t do this suggests these 18 month-olds had learned this deep, profound fact about human nature the three months from when they were 15 months old. So children both know more learn more than we ever would have thought. And this is just one of hundreds hundreds of studies over the last 20 years that’s demonstrated it.
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The question you might ask though is: do children learn so much? And how is it for them to learn so much in such a time? I mean, after all, if you look at babies superficially, they pretty useless. And actually in many ways, they’re worse than useless, we have to put so much time and energy into just keeping them alive. But if turn to evolution for an answer to this puzzle of why we spend much time taking care of useless babies, it turns out that there’s actually an answer. we look across many, many different species of animals, not just us primates, also including other mammals, birds, even marsupials like kangaroos and wombats, it 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 smart and flexible they are.
And sort of posterbirds for this idea are the birds up there. On one side is a Caledonian 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 to use a tool to get food. On the other hand, we have our friend domestic chicken. And chickens and ducks and geese and are basically as dumb as dumps. So they’re very, very good at for grain, and they’re not much good at doing anything else. Well it out that the babies, the New Caledonian crow babies, fledglings. They depend on their moms to drop worms their little open mouths for as long as two years, which a really long time in the life of a bird. Whereas the chickens actually mature within a couple of months. So childhood is reason why the crows end up on the cover of and the chickens end up in the soup pot.
There’s something about long childhood that seems to be connected to knowledge and learning. what kind of explanation could we have for this? some animals, like the chicken, seem to be beautifully suited to doing just one very well. So they seem to be beautifully suited to pecking grain in one environment. creatures, like the crows, aren’t very good at doing anything in particular, but they’re 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 our bodies by far any other animal. We’re smarter, we’re more flexible, we can learn more, we survive in different environments, we migrated to cover the world and even go to space. And our babies and children are dependent on us for much longer than the babies of other species. My son is 23. (Laughter) And at until they’re 23, we’re still popping those worms into those 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 has one disadvantage. And that 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 mastodon charging at you be saying to yourself, “A slingshot or maybe a spear might work. Which would actually be better?” You to know all that before the mastodons actually show up. And the way evolutions seems to have solved that problem is with a kind of division of labor. So the is that we have this early period when we’re completely protected. 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 put them to work to do things out there in the world.
So one way thinking about it is that babies and young children like the research and development division of the human species. So they’re the protected blue guys who just have to go out and learn and have good ideas, and we’re production marketing. We have to take all those ideas that we when we were children and actually put them to use. way of thinking about it is instead of thinking babies and children as being like defective grownups, we think about them as being a different developmental stage of the species — kind of like 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 along our narrow, grownup, adult path.
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If is true, if these babies are designed to learn — and this story would say children are for learning, that’s what they’re — we might expect that they would have really powerful mechanisms. And in fact, the baby’s brain seems to be the most powerful computer on the planet. But real computers are actually getting to be a lot better. And there’s a revolution in our understanding of machine learning recently. And all depends on the ideas of this guy, the Thomas Bayes, who 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 do is have a hypothesis that they think might be likely to start with. They go out and test against the evidence. The evidence makes them change that hypothesis. Then test that new hypothesis and so on and so forth. And what Bayes was a mathematical way that you could do that. And that mathematics is at core of the best machine learning programs that we now. And some 10 years ago, I suggested that babies might be doing the same thing.
So if want to know what’s going on underneath those beautiful eyes, I think it actually looks something like this. This Reverend Bayes’s notebook. So I think those babies are actually making complicated calculations with conditional probabilities that they’re to figure out how the world works. All right, that might seem like an even taller order to actually demonstrate. Because after all, if you even grownups about statistics, they look extremely stupid. How could it be children are doing statistics?
So to test this we used a that we have called the Blicket Detector. This is a box that lights and plays music when you put some things on and not others. And using this very simple machine, my lab and others done dozens of studies showing just how good babies at learning about the world. Let me mention just one that we with Tumar Kushner, my student. If I showed you this detector, would be likely to think to begin with that way to make the detector go would be to a block on top of the detector. But actually, detector works in a bit of a strange way. if you wave a block over the top of the detector, something you wouldn’t ever think to begin with, the detector will actually activate two out of three times. Whereas, if do the likely thing, put the block on the detector, it will activate two out of six times. So the unlikely hypothesis actually has stronger evidence. It looks if the waving is a more effective strategy than 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 enough, the four year-olds used the evidence to wave object on top of the detector.
Now there are things that are really interesting about this. The first one is, again, remember, these are year-olds. They’re just 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 that to get to an idea, get to a hypothesis the world, that seems very unlikely to begin with. And in studies we’ve been doing in my lab, similar studies, we’ve show four year-olds are actually better at finding out an unlikely than adults are when we give them exactly the task. So in these circumstances, the children are using statistics to out about the world, but after all, scientists also do experiments, and we wanted to see children are doing experiments. When children do experiments we 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 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 through five hypotheses in the space of two minutes.
(Video) Boy: How this? Same as the other side.
Alison Gopnik: Okay, so his hypothesis has just been falsified.
(Laughter)
Boy: This one up, and this one nothing.
AG: Okay, he’s got his 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 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 this, to try putting it out onto the other location. Not working either.
Boy: Oh, because light goes only to 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 up. So when you put four. So you put on this one to make it light up and two this one to make it light up.
AG: Okay,there’s fifth hypothesis.
Now that is a particularly — that a 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 of four year-olds.
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Well, what’s it like to be kind of creature? What’s it like to be one of these brilliant butterflies who can test hypotheses in two minutes? Well, if you go back to those psychologists and philosophers, a lot of have said that babies and young children were barely conscious if were conscious at all. And I think just the opposite true. I think babies and children are actually more conscious than are as adults. Now here’s what we know about adult consciousness works. And adults’ attention and consciousness look kind of like a spotlight. So happens for adults is 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 even know something about the way the brain does this.
So what happens when we pay attention is that the cortex, the sort of executive part of our brains, sends a signal that makes little part of our brain much more flexible, more plastic, better learning, and shuts down activity in all the rest of our brains. we have a very focused, purpose-driven kind of attention. If we at babies and young children, we see something very different. think babies and young children seem to have more of a of consciousness than a spotlight of consciousness. So babies and young children are very at narrowing down to just one thing. But they’re very good at taking in lots of from lots of different sources at once. And if you actually in their brains, you see that they’re flooded with these neurotransmitters that really good at inducing learning and plasticity, and the inhibitory parts haven’t come on yet. So when say that babies and young children are bad at paying attention, what we really mean is that they’re at not paying attention. So they’re bad at getting rid of the interesting things that could tell them something and just looking the thing that’s important. That’s the kind of attention, kind of consciousness, that we might expect from those butterflies who are designed to learn.
Well if want to think about a way of getting a taste 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 been in before — when we fall in love someone new, or when we’re in a new city the first time. And what happens then is not that consciousness contracts, it expands, so that those three days Paris seem to be more full of consciousness and than all the months of being a walking, talking, meeting-attending zombie back home. And by the 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 for first time after you’ve had three double-espressos. (Laughter) That’s fantastic way to be, but it does tend to leave you waking up 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 are. It’s good to be a grownup. We can do things like our shoelaces and cross the street by ourselves. And makes sense that we put a lot of effort into making babies think adults do. But if what we want is to like those butterflies, to have open-mindedness, open learning, imagination, creativity, innovation, maybe at least some of the time we should getting the adults to start thinking more like children.
(Applause)