What going on in this baby’s mind? If you’d asked people this 30 years ago, most people, including psychologists, have said that this baby was irrational, illogical, egocentric — that couldn’t take the perspective of another person or understand cause and effect. In the last 20 years, developmental has completely overturned that picture. So in some ways, we that this baby’s thinking is like the thinking of the brilliant scientists.
Let me give you just one example of this. One thing that this baby could thinking about, that could be going on in his mind, is trying to figure what’s going on in the mind of that other baby. After all, of the things that’s hardest for all of us to do is to figure out other people are thinking and feeling. And maybe the hardest thing all is to figure out that what other people think feel isn’t actually exactly like what we think and feel. Anyone who’s politics can testify to how hard that is for some to get. We wanted to know if babies and young children could understand this profound thing about other people. Now the question is: How could ask them? Babies, after all, can’t talk, and if you a three year-old to tell you what he thinks, you’ll get is a beautiful stream of consciousness monologue about ponies birthdays and things like that. So how do we ask them the question?
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Well it turns that the secret was broccoli. What we did — 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 goldfish crackers. Now all of the babies, even in Berkley, like the crackers don’t like the raw broccoli. (Laughter) But then what Betty did was to take a little of food from each bowl. And she would act as if liked it or she didn’t. So half the time, she acted if she liked the crackers and didn’t like the — just like a baby and any other sane person. But the time, what she would do is take a bit of the broccoli and go, “Mmmmm, broccoli. I tasted the broccoli. Mmmmm.” And she would take a little bit of the crackers, 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. then she would simply put her hand out and say, “Can give me some?”
So the question is: What would baby give her, what they liked or what she liked? And the remarkable was that 18 month-old babies, just barely walking and talking, would give the crackers if she liked the crackers, but they would her the broccoli if she liked the broccoli. On the other hand, 15 month-olds would 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 a long time, they would just her the crackers, what they thought everybody must like. So there are two really things about this. The first one is that these little 18 month-old babies have 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 do things to help other people get what they wanted.
Even 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 more than we ever would have thought. And this just one of hundreds and hundreds of studies over the 20 years that’s actually demonstrated it.
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The question you might ask though is: Why do children so much? And how is it possible for them to learn so much in such short time? I mean, after all, if you look babies superficially, they seem pretty useless. And actually in ways, they’re worse than useless, because we have to so much time and energy into just keeping them alive. But we turn to evolution for an answer to this of why we spend so much time taking care of babies, it turns out that there’s actually an answer. If we look across many, different species of animals, not just us primates, but also including other mammals, birds, even marsupials like kangaroos wombats, it turns out that there’s a relationship between how long a childhood species has and how big their brains are compared to bodies and how smart and flexible they are.
And sort of the posterbirds this idea are the birds up there. On one side a New Caledonian crow. And crows and other corvidae, ravens, rooks and so forth, incredibly smart birds. They’re as smart as chimpanzees in respects. And this is a bird on the cover of science who’s how to use a tool to get food. On the other hand, we have friend the domestic chicken. And chickens and ducks and geese and turkeys basically as dumb as dumps. So they’re very, very good at for grain, and they’re not much good at doing else. Well it turns out that the babies, the New Caledonian crow babies, fledglings. They depend on their moms to drop worms in their open mouths for as long as two years, which is a really time in the life of a bird. Whereas the chickens are actually mature within couple 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 learning. Well what kind of explanation could we have this? Well some animals, like the chicken, seem to be beautifully to doing just one thing very well. So they seem to beautifully suited to pecking grain in one environment. Other creatures, like the crows, aren’t good at doing anything in particular, but they’re extremely good at learning laws of different environments.
And of course, we human beings are way out on the of the distribution like the crows. We have bigger brains relative to our by far than 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 for much longer than the babies of any other species. son is 23. (Laughter) And at least until they’re 23, we’re still those worms into those little open mouths.
All right, why would we see this correlation? Well an is that that strategy, that learning strategy, is an extremely powerful, great strategy for getting on 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 helpless. So you don’t want to have the mastodon charging you and be saying to yourself, “A slingshot or maybe a spear might work. Which would actually better?” You want to know all that before the mastodons actually show up. And way the evolutions seems to have solved that problem is a kind of division of labor. So the idea 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 then adults, we can take all those things that we when we were babies and children and actually put them to work do things out there in the world.
So one way of thinking about it is that babies young children are like the research and development division of human species. So they’re the protected blue sky guys who have to go out and learn and have good ideas, we’re production and marketing. We have to take all ideas that we learned when we were children and actually them to use. Another way of thinking about it is instead of of babies and children as being like defective grownups, we should about them as being a different developmental stage of the same — kind of like caterpillars and butterflies — except that they’re actually brilliant 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 is true, these babies are designed to learn — and this evolutionary story would say children are learning, that’s what they’re for — we might expect that they would really powerful learning mechanisms. And in fact, the baby’s brain to be 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 machine learning recently. And it all depends on the ideas of this guy, Reverend Thomas Bayes, who was a statistician and mathematician the 18th century. And essentially what Bayes did was to a mathematical way using probability theory to characterize, describe, the way that find out about the world. So what scientists do is they have a hypothesis they think might be likely to start with. They go and test it against the evidence. The evidence makes change that hypothesis. Then they test that new hypothesis and so on so forth. And what Bayes showed was a mathematical way that you could do that. And that mathematics at the core of the best machine learning programs that have now. And some 10 years ago, I suggested that babies be doing the same thing.
So if you want know what’s going on underneath those beautiful brown eyes, I think it actually something like this. This is 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 world works. right, now that might 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 doing statistics?
So to test this we a machine that we have called the Blicket Detector. This a box 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 done dozens of studies showing just how good babies are at learning about the world. Let me mention one that we did with Tumar Kushner, my student. If I showed you this detector, you would likely to think to begin with that the way make the detector go would be to put a block on top of detector. But actually, this detector works in a bit of a strange way. Because you wave a block over the top of the detector, you wouldn’t ever think of to begin with, the detector will actually two out of three times. Whereas, if you do the likely thing, put the block on detector, it will only activate two out of six times. So the hypothesis actually has stronger evidence. It looks as if 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 them to make it go. And sure enough, the year-olds used 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, are four year-olds. They’re just learning how to count. unconsciously, they’re doing these quite complicated calculations that will them a conditional probability measure. And the other interesting is that they’re using that evidence to get to idea, get to a hypothesis about the world, that seems 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 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 see if children are doing experiments. When children do experiments call it “getting into everything” or else “playing.”
And there’s been a bunch of studies recently that have shown this playing around 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 that this little boy will go through hypotheses in the space of two minutes.
(Video) Boy: How about this? Same as the side.
Alison Gopnik: Okay, so his first hypothesis has just been falsified.
(Laughter)
Boy: This one up, and this one nothing.
AG: Okay, he’s got his experimental notebook out.
Boy: What’s making light up. (Laughter) I don’t know.
AG: Every scientist will that expression of despair.
(Laughter)
Boy: Oh, it’s because needs to be like this, and this needs to be this.
AG: Okay, hypothesis two.
Boy: That’s why. Oh.
(Laughter)
AG: Now this is his next idea. He told experimenter to do this, to try putting it out onto the location. Not working either.
Boy: Oh, because the light goes to here, not here. Oh, the bottom of this box has electricity here, but this doesn’t have electricity.
AG: Okay, that’s a fourth hypothesis.
Boy: It’s lighting up. So when put four. So you put four on this one to make it light up and two on one 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, 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 really do is do a of experiments. This is actually pretty typical of four year-olds.
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Well, what’s like to be this kind of creature? What’s it to be one of these brilliant butterflies who can test five hypotheses in two minutes? Well, you go back to those psychologists and philosophers, a lot of them said that babies and young children were barely conscious if they were conscious at all. And think just the opposite is true. I think babies children are actually more conscious than we are as adults. here’s what we know about how adult consciousness works. And adults’ attention and consciousness look of like a spotlight. So what happens for adults is we decide that something’s or important, we should pay attention to it. Our consciousness of that thing that we’re attending to becomes bright and vivid, and everything else sort of goes dark. And we even know something about the way brain does this.
So what happens when we pay attention is that the prefrontal cortex, the sort executive part of our brains, sends a signal that makes a little part of brain much more flexible, more plastic, better at learning, and shuts down activity in all the rest of brains. So we have a very focused, purpose-driven kind of attention. If we look at babies and children, we see something very different. I think babies young children seem to have more of a lantern of 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 look in their brains, you see that they’re flooded with these neurotransmitters are really good at inducing learning and plasticity, and the parts haven’t come on yet. So when we say that and young children are bad at paying attention, what we really is that they’re bad at not paying attention. So they’re bad at getting rid of all the things that could tell them something and just looking the thing that’s important. That’s the kind of attention, the kind of consciousness, that we might from those butterflies who are designed to learn.
Well if we to think about a way of getting a taste of that kind of baby consciousness adults, I think the best thing is think about cases we’re put in a new situation that we’ve never been in before — when fall in love with 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 of being 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 effect those baby neurotransmitters. So what’s it like to be 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 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 and cross the by ourselves. And it makes sense that we put a lot effort into making babies think like adults do. But if what we want is to be those butterflies, to have open-mindedness, open learning, imagination, creativity, innovation, maybe at least of the time we should be getting the adults start thinking more like children.
(Applause)