What is going on in this baby’s mind? you’d asked people this 30 years ago, most people, psychologists, would have said that this baby was irrational, illogical, — that he couldn’t take the perspective of another person understand cause and effect. In the last 20 years, developmental science has overturned that picture. So in some ways, we think that baby’s thinking is like the thinking of the most scientists.
Let me give you just one example of this. One thing this baby could be thinking about, that could be on in his mind, is trying to figure out what’s going on in the of that other baby. After all, one of the things that’s hardest for of us to do is to figure out what other people are thinking and feeling. And maybe the thing of 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 to how hard is for some people to get. We wanted to know if babies and children could understand this really profound thing about other people. the question is: How could we ask them? Babies, all, can’t talk, and if you ask a three year-old to tell you what he thinks, what you’ll get a beautiful stream of consciousness monologue about ponies and birthdays 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 — was actually to give the babies bowls of food: one bowl of raw broccoli and one bowl of delicious goldfish crackers. Now all of babies, even in Berkley, like the crackers and don’t the raw broccoli. (Laughter) But then what Betty did was to a little taste of food from each bowl. And would act as if she liked it or she didn’t. half the time, she acted as if she liked the crackers and didn’t like the broccoli — just a baby and any other sane person. But half the time, what she would do take a little bit of the broccoli and go, “Mmmmm, broccoli. I tasted the broccoli. Mmmmm.” And then she take a little bit of the 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 hand out say, “Can you give me some?”
So the question is: What would baby give her, what they liked or what she liked? And the remarkable thing that 18 month-old babies, just barely walking and talking, would give her the if she liked the crackers, but they would give her the broccoli if she the broccoli. On the other hand, 15 month-olds would stare her for a long time if she acted as she liked the broccoli, like they couldn’t figure this out. But then they stared for a long time, they would just give her the crackers, 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 human nature, that don’t always want 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 do suggests that these 18 month-olds had learned this deep, profound about human nature in the three months from when they 15 months old. So children both know more and learn more we ever would have thought. And this is just one of hundreds and hundreds studies over the last 20 years that’s actually 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, seem pretty useless. And actually in many ways, they’re worse than useless, because we have to put much time and energy into just keeping them alive. But if we to evolution for an answer to this puzzle of why spend so much time taking care of useless babies, it turns that there’s actually an answer. If we look across many, many different of animals, not just us primates, but also including mammals, birds, even marsupials like kangaroos and wombats, it out that there’s a relationship between how long a childhood a has and how big their brains are compared to their bodies and how smart and flexible are.
And sort of the posterbirds for this idea are the birds up there. one side is a New Caledonian crow. And crows other corvidae, ravens, rooks and so forth, are incredibly smart birds. They’re as smart as in some 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 turkeys are basically as dumb as dumps. they’re very, very good at pecking for grain, and they’re not much good at anything else. Well it turns out that the babies, New Caledonian crow babies, are fledglings. They depend on moms to drop worms in their little open mouths for as long as two years, which a really long time in the life of a bird. Whereas the chickens are actually mature a couple of months. So childhood is the reason why the crows end up on the of Science and the chickens end up in the soup pot.
There’s something that long childhood that seems to be connected to knowledge learning. Well what kind of explanation could we have for this? Well some animals, like chicken, seem to be beautifully suited to doing just one thing well. So they seem to be beautifully suited to grain in one environment. Other creatures, like the crows, aren’t very at doing anything in particular, but they’re extremely good at about laws of different environments.
And of course, we human beings are way out on the end of 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 cover the world and even go to outer space. our babies and children are dependent on us for longer than the babies of any other species. My son 23. (Laughter) And at least until they’re 23, we’re still those worms into those little open mouths.
All right, would we see this correlation? Well an idea is that that strategy, learning strategy, is an extremely powerful, great strategy for on in the world, but it has one big disadvantage. And that one disadvantage is that, until you actually do all that learning, you’re going to be helpless. you don’t want to have the mastodon charging at you and be saying to yourself, “A slingshot maybe a spear might work. Which would actually be better?” You want to all that before the mastodons actually show up. And the way the seems to have solved that problem is with a of division of labor. So the idea is that we have this early period when we’re protected. We don’t have to do anything. All we have to do is learn. And then adults, we can take all those things that we learned when we babies and children and actually put them to work to do things out there in the world.
So way of thinking about it is that babies and young children are like the research development division of the human species. So they’re the protected sky guys who just have to go out and and have good ideas, and we’re production and marketing. We have to take all ideas that we learned when we were children and actually put to use. Another way of thinking about it is instead of of babies and children as being like defective grownups, we should think about as being a different developmental stage of the same species — kind of caterpillars and butterflies — except that they’re actually the brilliant who are flitting around the garden and exploring, and we’re the caterpillars who are inching our narrow, grownup, adult path.
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If this true, if these babies are designed to learn — this evolutionary story would say children are for learning, that’s what they’re for — we might that they would have really powerful learning mechanisms. And in fact, the baby’s brain seems to the most powerful learning computer on the planet. But real computers are actually to be a lot better. And there’s been a revolution in our understanding of machine learning recently. And all depends on the ideas of this guy, the Reverend Thomas Bayes, who was a statistician and 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 about world. So what scientists do is they have a hypothesis that they might be likely to start with. They go out test it against the evidence. The evidence makes them change that hypothesis. they test that new hypothesis and so on and so forth. what Bayes showed was a mathematical way that you could do that. And that mathematics is at the of the best machine learning programs that we have now. some 10 years ago, I suggested that babies might 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 complicated with conditional probabilities that they’re revising 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 that children doing statistics?
So to test this we used a machine that we have called the Blicket Detector. is a box that lights up and plays music when you put some on it and not others. And using this very simple machine, my and others have done dozens of studies showing just how good are at learning about the world. Let me mention just that we did with Tumar Kushner, my student. If showed you this detector, you would be likely to think to with that the way to make the detector go would be to put a on top of the detector. But actually, this detector in a bit of a strange way. Because if you wave a 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 you do the thing, put the block on the detector, it will only activate two out of times. So the unlikely hypothesis actually has stronger evidence. It as if the waving is a more effective strategy than the strategy. So we did just this; we gave four year-olds this pattern of evidence, and we asked them to make it go. And sure enough, four year-olds used the evidence to wave the object on top the detector.
Now there are two things that are really about this. The first one is, again, remember, these are four year-olds. They’re just learning how count. But unconsciously, they’re doing these quite complicated calculations that give them a conditional probability measure. And the other thing is that they’re using that 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, studies, we’ve show that four year-olds are actually better at finding an unlikely hypothesis than adults are when we give them exactly the same task. So in these circumstances, children are using statistics to find out about the world, after all, scientists also do experiments, and we wanted to see if children doing experiments. When children do experiments we call it “getting everything” or else “playing.”
And there’s been a bunch of interesting recently that have shown this playing around is really kind of experimental research program. Here’s one from Cristine Legare’s lab. What Cristine did was our Blicket Detectors. And what she did was show children that yellow made it go and red ones didn’t, and then she showed an anomaly. And what you’ll see is that this little boy will go through five hypotheses in the of two minutes.
(Video) Boy: How about this? Same the other side.
Alison Gopnik: Okay, so his first has just been falsified.
(Laughter)
Boy: This one lighted up, 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 will recognize that expression of despair.
(Laughter)
Boy: Oh, it’s because this needs to be this, and this 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, try putting it out onto the other location. Not working either.
Boy: Oh, because light goes only to here, not here. Oh, the bottom this box has electricity in here, but this doesn’t electricity.
AG: Okay, that’s a fourth hypothesis.
Boy: It’s up. So when you put four. So you put four on one to make it light up and two on this to make it light up.
AG: Okay,there’s his fifth hypothesis.
Now that a particularly — that is a particularly adorable and articulate little boy, what Cristine discovered is this is actually quite typical. If you look the way children play, when you ask them to explain something, what they 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 this kind of creature? What’s it like be one of these brilliant butterflies who can test five hypotheses two minutes? Well, if you go back to those psychologists and philosophers, a lot them have said that babies and young children were barely if they 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 how adult consciousness works. adults’ attention and consciousness look kind of like a spotlight. what happens for adults is we decide that something’s or important, we should pay attention to it. Our consciousness that thing that we’re attending to becomes extremely bright and vivid, everything else sort of goes dark. And we even something about 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 a that makes a little part of our brain much flexible, more plastic, better at learning, and shuts down activity all the rest of our brains. So we have a very focused, purpose-driven kind attention. If we look at babies and young children, we see something different. I think babies and young children seem to have more a lantern of consciousness than a spotlight of consciousness. So babies young children are very bad at narrowing down to 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 neurotransmitters that are really good at inducing learning and plasticity, 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 that they’re bad at not paying attention. So they’re bad at rid of all the interesting things that could tell them something just looking at the thing that’s important. That’s the of attention, the kind of consciousness, that we might expect from butterflies who are designed to learn.
Well if we want to think about way of getting a taste of that kind of baby consciousness adults, I think the best thing is think about cases where we’re put in a new that we’ve never been in before — when we fall in love someone new, or when we’re in a new city for the time. And what happens then is not that our contracts, it expands, so that those three days in Paris seem to more full 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 like to be a baby? It’s like being in love in Paris for the first time you’ve had three double-espressos. (Laughter) That’s a fantastic way be, but it does tend to leave you waking crying at three o’clock in the morning.
(Laughter)
Now it’s good be a grownup. I don’t want to say too about how wonderful babies are. It’s good to 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 think like adults do. But if what we want is to be like those butterflies, have open-mindedness, open learning, imagination, creativity, innovation, maybe at least some of the time we should be the adults to start thinking more like children.
(Applause)