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 baby irrational, illogical, egocentric — that he couldn’t take the perspective of another person or understand cause effect. In the last 20 years, developmental science has overturned that picture. So in some ways, we think this baby’s thinking is like the thinking of the most brilliant scientists.
Let me give you just one of this. One thing that this baby could be about, that could be going on in his mind, trying to figure out what’s going on in the mind of that baby. After all, one of the things that’s hardest for all us to do is to figure out what other people thinking and feeling. And maybe the hardest thing of all is to figure out that what people think and feel isn’t actually exactly like what we think and feel. Anyone who’s followed politics testify to how hard that is for some people to get. We to know if babies and young children could understand this really profound about other people. Now the question is: How could we ask them? Babies, after all, can’t talk, and you ask a three year-old to tell you what thinks, what you’ll get is a beautiful stream of consciousness monologue about and birthdays and 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 we did — Rapacholi, who was one of my students, and I — actually to give the babies two bowls of food: one bowl of raw broccoli and one bowl of goldfish crackers. Now all of the babies, even in Berkley, like the 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 if she liked or she didn’t. So half the time, she acted as if she liked the and didn’t like the broccoli — just like a baby and any other sane person. But half time, what she would do is take a little 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 the crackers. Eww, yuck.” So she’d act if what she wanted was just the opposite of what the wanted. We did this with 15 and 18 month-old babies. And she would simply put her hand out and say, “Can give me some?”
So the question is: What would the 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, but would give her the broccoli if she liked the broccoli. On the hand, 15 month-olds would stare at her for a long time 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, they thought everybody must like. So there are two really remarkable things about this. The first one is these little 18 month-old babies have already discovered this really profound fact about human nature, that we don’t want the same thing. And what’s more, they felt that they should actually things to help other people 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 deep, profound fact about human nature in the three from when they were 15 months old. So children know more and learn more than we ever would thought. And this is just one of hundreds and hundreds of studies over 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 in such a time? I mean, after all, if you look at babies superficially, they seem pretty useless. And in many ways, they’re worse than useless, because we have to so much time and energy into just keeping them alive. But if we turn to evolution for an 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 animals, not just us primates, but also including other mammals, birds, even like kangaroos and wombats, it turns out that there’s a between how long a childhood a species has and how big their brains are compared their bodies and how smart and flexible they are.
And of the posterbirds for this idea are the birds there. On one side is a New Caledonian crow. And crows and other corvidae, ravens, and so forth, are incredibly smart birds. They’re as smart as chimpanzees some respects. And this is a bird on the cover science who’s learned how to use a tool to get food. the other hand, we have our friend the domestic chicken. And chickens ducks and geese and turkeys are basically as dumb dumps. So 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, the New crow babies, are fledglings. They depend on their moms to drop in their little open mouths for as long as two years, which is really long time in the life of a bird. the chickens are actually mature within a couple of months. So childhood is the why the crows end up on the cover of Science and the chickens up in the soup pot.
There’s something about that long childhood that seems be connected to knowledge and learning. Well what kind of explanation could we for this? Well some animals, like the chicken, seem to be beautifully suited doing just one thing very well. So they seem 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 of environments.
And of course, we human beings are way out on the end the distribution like the crows. We have bigger brains relative to 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 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) And at least until they’re 23, we’re popping those worms into those little open mouths.
All right, would we see this correlation? Well an idea is that that strategy, that strategy, is an extremely powerful, great strategy for getting in the world, but it has one big disadvantage. And that one big disadvantage is that, until you 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 maybe a spear might work. Which would actually be better?” want to know all that before the mastodons actually up. And the way the evolutions seems to have solved 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 have to anything. All we have to do is learn. And as adults, we can take all those things that learned when we were babies and children and actually them to work to do things out there in world.
So one way of thinking about it is that babies and children are like the research and development division of human species. So they’re the protected blue sky guys just have to go out and learn and have good ideas, we’re production and marketing. We have to take all those ideas that we learned when were children and actually put them to use. Another way thinking about it is instead of thinking of babies and children as like defective grownups, we should think about them as being a different developmental stage of the same — kind of like caterpillars and butterflies — except that they’re actually the butterflies who are flitting around the garden and exploring, we’re the caterpillars who are inching along 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 expect they would have really powerful learning mechanisms. And in fact, the baby’s brain seems be the most powerful learning 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. And all depends on the ideas of this guy, the Thomas Bayes, who was a statistician and mathematician in the 18th century. essentially what Bayes did was to provide a mathematical way probability theory to characterize, describe, the way that scientists find about the world. So what scientists do is they have a hypothesis they think might be likely to start with. They go out test it against the evidence. The evidence makes them change that hypothesis. Then they that new hypothesis and so on and so forth. And what Bayes showed was a mathematical way that could do that. And that mathematics is at the core of best machine learning programs that we have now. And some 10 years ago, I suggested babies might be doing the same thing.
So if want to know what’s going on underneath those beautiful brown eyes, I think it actually looks something this. This is Reverend Bayes’s notebook. So I think those babies are making complicated calculations with conditional probabilities that they’re revising to figure out the world works. All right, now that might seem an even taller order to 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 the Blicket Detector. This is a box lights up and plays music when you put some things it and not others. And using this very simple machine, my lab others have done dozens of studies showing just how babies are at learning about the world. Let me mention just one that we with Tumar Kushner, my student. If I showed you detector, you would be likely to think to begin that the way to make the detector go would be to put block on top of the detector. But actually, this 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 of to begin with, the detector will actually activate two out three times. Whereas, if you do the likely thing, the block on the detector, it will only activate two out six times. So the unlikely hypothesis actually has stronger evidence. looks as if the waving is a more effective strategy than the other strategy. So did just this; we gave four year-olds this pattern of evidence, and we just asked them make it go. And sure enough, the four year-olds the evidence to wave the object on top of the detector.
Now are two things that are really interesting about this. The first one is, again, remember, these four year-olds. They’re just learning how to count. But unconsciously, they’re doing these quite complicated calculations that will give them 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 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 statistics to find out about the world, but after all, also do experiments, and we wanted to see if children are doing experiments. children do experiments 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 one from Cristine Legare’s lab. What did was use our Blicket Detectors. And what she did was show children that yellow ones made it and red ones didn’t, and then she showed them anomaly. And what you’ll see is that this little boy go through 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 nothing.
AG: Okay, he’s got his experimental notebook out.
Boy: What’s this light up. (Laughter) I don’t know.
AG: Every scientist will recognize that of despair.
(Laughter)
Boy: Oh, it’s because this needs to be like this, and this needs to like this.
AG: Okay, hypothesis two.
Boy: That’s why. Oh.
(Laughter)
AG: Now this is his next idea. told the experimenter to do this, to try putting it out the other location. Not working either.
Boy: Oh, because the goes only 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 to make it light up and on this one to make it light up.
AG: Okay,there’s his fifth hypothesis.
Now that is a particularly — is a particularly adorable and articulate little boy, but what Cristine discovered this is actually quite typical. If you look at the children play, when you ask them to explain something, what they do is do a series of experiments. This is pretty typical of four year-olds.
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Well, what’s it like to be this of creature? What’s it like to be one of these butterflies who can test five hypotheses in two minutes? Well, if you go to those psychologists and philosophers, a lot of them said that babies and young children were barely conscious if they were conscious at all. I think just the opposite is true. I think babies and are actually more conscious than we are as adults. Now here’s we know about how adult consciousness works. And adults’ and consciousness look kind of like a spotlight. So what happens for adults is decide that something’s relevant or important, we should pay attention to it. Our consciousness of that thing we’re attending to becomes extremely bright and vivid, and everything sort of goes dark. And we even know something about the way brain does this.
So what happens when we pay is that the prefrontal cortex, the sort of executive part our brains, sends a signal that makes a little of our brain much more flexible, more plastic, better at learning, and shuts down activity in the rest of our brains. So we have a very focused, purpose-driven kind of attention. If look at babies and young children, we see something very different. think babies and young children seem to have more of lantern of consciousness than a spotlight of consciousness. So babies and young are very bad at narrowing down to just one thing. But they’re very at taking in lots of information from lots of sources at once. And if you actually look in their brains, see that they’re flooded with these neurotransmitters that are really good at inducing and plasticity, and the inhibitory parts haven’t come on yet. So when say that babies and young children are bad at paying attention, we really mean is that they’re bad at not attention. So they’re bad at getting rid of all the interesting things that tell them something and just looking at the thing that’s important. That’s kind of attention, the kind of consciousness, that we expect from those butterflies who are designed to learn.
Well we want to think about a way of getting taste of that kind of baby consciousness as adults, think the 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 with someone new, or when we’re in new city for the first time. And what happens then is that our consciousness contracts, it expands, so that those three days in seem to be more full of consciousness and experience than all the months of being a walking, talking, 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 a baby? It’s like in love in Paris for the first time after you’ve had double-espressos. (Laughter) That’s a fantastic way to be, but does tend to leave you waking up crying at o’clock in the morning.
(Laughter)
Now it’s good to 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 our shoelaces cross the street by ourselves. And it makes sense we put a lot of effort into making babies think like do. But if what we want is to be like those butterflies, to have open-mindedness, learning, imagination, creativity, innovation, maybe at least some of time we should be getting the adults to start thinking more children.
(Applause)