What is going in this baby’s mind? If you’d asked people this 30 years ago, 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 effect. In the last 20 years, developmental science has completely overturned picture. So in some ways, we think that this baby’s thinking is like the thinking of the brilliant scientists.
Let me give you just one example this. One thing that this baby could be thinking about, that could be on in his mind, is trying to figure out what’s going on the mind of that other baby. After all, one of the 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 and feel isn’t actually exactly like what we and feel. Anyone who’s followed politics can testify to how hard that for some people to get. We wanted to know if babies young children could understand this really profound thing about other people. Now question is: How could we ask them? Babies, after all, can’t talk, if you ask a three year-old to tell you he thinks, what you’ll get is a beautiful stream of consciousness monologue about ponies and birthdays things like that. So how do we actually ask them question?
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Well it turns out that the secret was broccoli. we did — Betty Rapacholi, who was one of my students, I — was actually to give the babies two bowls 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 Betty did was to take a little taste of food from each bowl. And she act as if she liked it or she didn’t. So half time, she acted as if she liked the crackers didn’t like the broccoli — just like a baby any other sane person. But half the time, what she would is take a little bit of the broccoli and go, “Mmmmm, broccoli. I tasted 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 babies wanted. We did this with 15 and 18 month-old babies. And then would simply put her hand out and say, “Can give me some?”
So the question is: What would the baby give her, what they liked what she liked? And the remarkable thing was that 18 month-old babies, barely walking and talking, would give her the crackers she liked the crackers, but they would give her the broccoli if she liked the broccoli. On the hand, 15 month-olds would stare at her for a long if she acted as if she liked the broccoli, like they couldn’t this out. But then after they stared 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, that we don’t always want same thing. And what’s more, they felt that they should actually do things help other people get what 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, fact about human nature in the three months from when they were 15 months old. So children know more and learn more than we ever would have thought. And is just one of hundreds and hundreds of studies the last 20 years that’s actually demonstrated it.
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question you might ask though is: Why do children learn so much? And how is possible for them to learn so much in such 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 energy into just keeping them alive. But if we turn to for an answer to this puzzle of why we spend so much time taking care useless babies, it turns out that there’s actually an answer. If look across many, many different species of animals, not just primates, but also including other 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 and flexible they are.
And sort of the posterbirds for this are the birds up there. On one side is a New crow. And crows and other corvidae, ravens, rooks and so forth, are incredibly smart birds. They’re as smart chimpanzees in some respects. And this is a bird on the of science who’s learned how to use a tool to get food. On 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 good at doing anything else. Well it turns out 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 the life of a bird. the chickens are actually mature within a couple of months. So childhood the reason why the crows end up on the cover Science and the chickens end up in the soup pot.
There’s about that long childhood that seems to be connected knowledge and learning. Well what kind of explanation could we have this? Well some animals, like the chicken, seem to be beautifully suited to just one thing very well. So they seem to be beautifully suited to pecking in one environment. Other creatures, like the crows, aren’t very good at doing anything particular, but they’re extremely good at learning about laws of different environments.
And of course, we human are way out on the end of the distribution like the crows. have bigger brains relative to our bodies by far than any animal. We’re smarter, we’re more flexible, we can learn more, we in more different environments, we migrated to cover the world and even go to outer space. And babies and children are dependent on us for much longer the babies of any other species. My son is 23. (Laughter) at least until they’re 23, we’re still popping those worms those little open mouths.
All right, why would we see correlation? Well an idea is that that strategy, that learning strategy, is an powerful, great strategy for getting on in the world, but it has one big disadvantage. And that big disadvantage is that, until you actually do all that learning, you’re to be helpless. So you don’t want to have the mastodon charging at you and saying to yourself, “A slingshot or maybe a spear might work. Which would be better?” You want to know all that before the mastodons actually show up. And way the evolutions seems to have solved that problem is with a kind of of labor. So the idea is that we have 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 put them to to do things out there in the world.
So way of thinking about it is that babies and children are like the research and development division of the human species. So they’re the blue sky guys who just have to go out and and have good ideas, and we’re production and marketing. We have to take all those ideas that learned when we were children and actually put them to use. Another way of thinking it is instead of thinking of babies and children being like defective grownups, we should think about them as being a developmental stage of the same species — kind of like caterpillars butterflies — except that they’re actually the brilliant butterflies are flitting around the garden and exploring, and we’re the caterpillars who inching along our narrow, grownup, adult path.
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If this is true, if these babies are to learn — and this evolutionary story would say children for learning, that’s what they’re for — we might that they would have really powerful learning mechanisms. And in fact, baby’s brain seems to be the most powerful learning computer on the planet. But real are actually getting to be a lot better. And there’s been a revolution our understanding of machine learning recently. And it all depends on the ideas this guy, the Reverend Thomas Bayes, who was a statistician mathematician in the 18th century. And essentially what Bayes did was provide a mathematical way using probability theory to characterize, describe, way that scientists find out about the world. So scientists do is they have a hypothesis that they think be likely to start with. They go out and test it 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 that you do that. And that mathematics is at the core of the best machine learning programs that we 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, think it actually looks something like this. This is Bayes’s notebook. So I think those babies are actually making complicated calculations conditional probabilities that they’re revising to figure out how the works. All right, now that might seem like an taller order to actually demonstrate. Because after all, if you even grownups about statistics, they look extremely stupid. How could be that children are doing statistics?
So to test this used a machine that we have called the Blicket Detector. is a box that lights up and plays music when you put some things on it not others. And using this very simple machine, my lab and others have done of studies showing just how good babies are at learning about world. Let me mention just one that we did with 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, this detector in a bit of a strange way. Because if you a block over the top of the detector, something you wouldn’t ever think to begin with, the detector will actually activate two of three times. Whereas, if you do the likely thing, put the block the detector, it 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 just this; we gave year-olds this pattern of evidence, and we just asked them to it go. And sure enough, the four year-olds used the evidence to the object on top of the detector.
Now there are 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 quite complicated calculations that will give them a conditional probability measure. And the other interesting thing that they’re using that evidence to get to an idea, get to hypothesis about the world, that seems very unlikely to with. And in studies we’ve just been doing in lab, similar studies, we’ve show that four year-olds are actually better at out an unlikely hypothesis than adults are when we them exactly the same task. So in these circumstances, the children are using to find out about the world, but after all, scientists also do experiments, and we wanted to if children are doing experiments. When children do experiments we it “getting into everything” or else “playing.”
And there’s been bunch of interesting studies recently that have shown this playing around is really a of experimental research program. Here’s one from Cristine Legare’s lab. What Cristine did was use Blicket Detectors. And what she did was show children that ones made it go and red ones didn’t, and then she showed them an anomaly. 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 hypothesis has just been falsified.
(Laughter)
Boy: This lighted up, and this one nothing.
AG: Okay, he’s got experimental notebook out.
Boy: What’s making this light up. (Laughter) don’t know.
AG: Every scientist will recognize that expression 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 this is his next idea. He the experimenter to do this, to try putting it out onto the other location. working either.
Boy: Oh, because the 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 this one to it light up and two on this one to make it light up.
AG: Okay,there’s fifth hypothesis.
Now that is a particularly — that is a particularly adorable articulate little boy, but what Cristine discovered is this is actually quite typical. If look at the way children play, when you ask them to explain something, what they do 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 of these butterflies who can test five hypotheses in two minutes? Well, if you go back to psychologists and philosophers, a lot of them have said that and young children were barely conscious if they were conscious at all. And I think just opposite is true. I think babies and children are actually more conscious than we as adults. Now here’s what we know about how adult consciousness works. And adults’ attention and consciousness kind of like a spotlight. So what happens for is we decide that something’s relevant or important, we pay attention to it. Our consciousness of that thing that we’re attending becomes extremely bright and vivid, and everything else sort of goes dark. And we even know something the way the brain does this.
So what happens when we pay attention is the prefrontal cortex, the sort of executive part of brains, sends a signal that makes a little part of our much more flexible, more plastic, better at learning, and down activity in all the rest of our brains. we have a very focused, purpose-driven kind of attention. If we look at babies young 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 very bad at narrowing down to just one thing. they’re very good at taking in lots of information from lots different sources at once. And if you actually look their brains, you see that they’re flooded with these that are really good at inducing learning and plasticity, and the parts haven’t come on yet. So when we say that babies and young children are bad paying attention, what we really mean is that they’re bad not paying attention. So they’re bad at getting rid all the interesting things that could tell them something and just looking the thing that’s important. That’s the kind of attention, the 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 never been in — 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 contracts, it expands, so that those three days in Paris seem to more full of consciousness and experience than all the months of a 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 for first time after you’ve had three double-espressos. (Laughter) That’s a fantastic way to be, but it tend to leave you waking up crying at three o’clock in morning.
(Laughter)
Now it’s good to be a grownup. I don’t want to too much about how wonderful babies are. It’s good to a grownup. We can do things like tie our and cross the street by ourselves. And it makes sense that we put lot of effort into making babies think like adults do. But if we want is to be like those butterflies, to have open-mindedness, learning, imagination, creativity, innovation, maybe at least some of the time we should getting the adults to start thinking more like children.
(Applause)