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 was irrational, illogical, egocentric — that he couldn’t take the perspective another person or understand cause and effect. In the last 20 years, developmental science has completely that picture. So in some ways, we think that this baby’s thinking is like the thinking the most brilliant scientists.
Let me give you just one example this. One thing that this baby could be thinking about, could be going on in his mind, is trying to figure out what’s on in the mind of that other baby. After all, one the things that’s hardest for all of us to do is to figure out what other people are and feeling. And maybe the hardest thing of all to figure out that what other people think and isn’t actually exactly like what we think and feel. who’s followed politics can testify to how hard that for some people to get. We wanted to know if and young children could understand this really profound thing other people. Now the question is: How could we them? Babies, after all, can’t talk, and if you ask a year-old to tell you what he thinks, what you’ll get is beautiful stream of consciousness monologue about ponies and birthdays and things that. So how do we actually ask them the question?
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Well it turns out that the was broccoli. What we did — Betty Rapacholi, who was one of students, and I — was actually to give the babies two bowls food: one bowl of raw broccoli and one bowl of delicious goldfish crackers. Now all the babies, even in Berkley, like the crackers and don’t the raw broccoli. (Laughter) But then what Betty did was to take little taste of food from each bowl. And she would act as if liked it or she didn’t. So half the time, she acted as if she liked the crackers didn’t like the broccoli — just like a baby and any other sane person. But the time, what she would do is take a little of the broccoli and go, “Mmmmm, broccoli. I tasted the broccoli. Mmmmm.” And then she would take 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 baby give her, what they liked or she liked? And the remarkable thing was that 18 month-old babies, just walking and talking, would give her the crackers if she liked the crackers, but they give her the broccoli if she liked the broccoli. the other hand, 15 month-olds would stare at her a long time if she acted as if she the broccoli, like they couldn’t figure this out. But then after they stared a long time, they would just give her the crackers, what they thought everybody must like. So there are really remarkable 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 always want the same thing. what’s more, they felt that they should actually do to help other people get what they wanted.
Even more remarkably though, the fact that 15 month-olds didn’t this suggests that these 18 month-olds had learned this deep, profound fact about nature in the three months from when they were 15 months old. So both know more and learn more than we ever have thought. And this is just one of hundreds and hundreds of over the 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 so much in such a short time? I mean, all, if you look at babies superficially, they seem pretty useless. actually in many ways, they’re worse than useless, because we to put so much time and energy into just keeping them alive. But if we to evolution for an answer to this puzzle of why we spend much time taking care of useless babies, it turns that there’s actually an answer. If we look across many, many species of animals, not just us primates, but also other mammals, birds, even marsupials like kangaroos and wombats, it turns that there’s a relationship between how long a childhood a species and how big their brains are compared to their and how smart and flexible they are.
And sort of the for this idea are the birds up there. On 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 in some respects. And this a bird on the cover of science who’s learned to use a tool to get food. On the hand, we have our friend the domestic chicken. And chickens and ducks and geese and turkeys are basically dumb as dumps. So they’re very, very good at pecking for grain, and they’re much good at doing anything else. Well it turns that the babies, the New Caledonian crow babies, are fledglings. They depend on their moms to drop in their little open mouths for as long as two years, which is a long time in the life of a bird. Whereas the chickens are actually within a couple of months. So childhood is the reason why the crows end up on the cover Science and the chickens end up in the soup pot.
There’s something about that long childhood that to be connected to knowledge and learning. Well what kind of explanation could we have this? Well some animals, like the chicken, seem to be beautifully suited to doing just one very well. So they seem to be beautifully suited to grain 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 environments.
And of course, we human beings are way on the end of the distribution like the crows. We have bigger relative to our bodies by far than any other animal. We’re smarter, we’re more flexible, we can more, we survive in more different environments, we migrated to the world and even go to outer space. And babies and children are dependent on us for much longer than the babies of other species. My son is 23. (Laughter) And at least until they’re 23, we’re still popping those into those little open mouths.
All right, why would we see this correlation? Well idea is that that strategy, that learning strategy, is an powerful, great strategy for getting on in the world, but it has one disadvantage. And that one big disadvantage is that, until actually do all that learning, you’re going to be helpless. So you don’t want have the mastodon charging at you and be saying to yourself, “A or maybe a spear might work. Which would actually better?” You want to know all that before the actually show up. And the way the evolutions seems have solved that problem is with a kind of division labor. So the idea is that we have this early period when we’re completely protected. don’t have to do anything. All we have to do is learn. And then as adults, can take all those things that we learned when 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 the human species. they’re the protected blue sky guys who just have go out and learn and have good ideas, and we’re production and marketing. We have to all those ideas that we learned when we were children and actually put to use. Another way of 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 same species — kind of like caterpillars and butterflies — except that they’re actually the brilliant butterflies who flitting around the garden and exploring, and we’re the caterpillars who inching along our narrow, grownup, adult path.
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this is true, if these babies are designed to learn — this evolutionary story would say children are for learning, that’s what they’re for — we expect that they would have really powerful learning mechanisms. And in fact, the baby’s seems to be the most powerful learning computer on planet. But real computers are actually getting to be a lot better. And there’s been a revolution our understanding of machine learning recently. And it all on the ideas of this guy, the Reverend Thomas Bayes, who a statistician and mathematician in the 18th century. And essentially what Bayes did was to provide 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 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 you could do that. And that mathematics is at core of the best machine learning programs that we have now. And 10 years ago, I suggested that babies might be doing the same thing.
So if you to know what’s going on underneath those beautiful brown eyes, I think actually looks something like this. This is Reverend Bayes’s notebook. So I think those babies actually making complicated 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 demonstrate. Because after all, if you ask even grownups about statistics, look extremely stupid. How could it be that children are doing statistics?
So to test we used a machine that we have called the Blicket Detector. This is a box that lights up plays music when you put some things on it and not others. And this very simple machine, my lab and others have done dozens of showing just how good babies are at learning about the world. Let me mention just one that we with Tumar Kushner, my student. If I showed you this detector, you be likely to think to begin with that the to make the detector go would be to put a block on of the detector. But actually, this detector works in a bit a strange way. Because if you wave a block over top of the detector, something you wouldn’t ever think of to begin with, the detector will activate two out of three times. Whereas, if you do the likely thing, the block on the detector, it will only activate two out of six times. So the unlikely hypothesis has stronger evidence. It looks as if the waving is a effective strategy than the other strategy. So we did just this; we gave four year-olds this of evidence, and we just asked them to make it go. sure enough, the four year-olds used the evidence to the object on top of the detector.
Now there are two things that 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 give them a conditional probability measure. And the other interesting is 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 finding out an unlikely than adults are when we give them exactly the same task. So in these circumstances, the are using statistics to find out about the world, but all, scientists also do experiments, and we wanted to see if are doing experiments. When children do experiments we call “getting into everything” or else “playing.”
And there’s been a bunch of interesting studies that have shown this playing around is really a of experimental research program. Here’s one from Cristine Legare’s lab. What Cristine was use our Blicket Detectors. And what she did was show children 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 go five hypotheses in the space of two minutes.
(Video) Boy: How this? Same as the other side.
Alison Gopnik: Okay, his first hypothesis has just been falsified.
(Laughter)
Boy: one lighted 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 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 is his next idea. He told the experimenter to do this, to putting it out onto the other location. Not working either.
Boy: Oh, because light goes only to here, not here. Oh, the of this box has electricity in here, but this doesn’t have electricity.
AG: Okay, that’s fourth hypothesis.
Boy: It’s lighting up. So when you put four. So you four on this one to make it light up and two on this to make it light up.
AG: Okay,there’s his fifth hypothesis.
Now that is a — that is a particularly adorable and articulate little boy, but what discovered is this is actually quite typical. If you look at the way play, when you ask them to explain something, what they really do is do a series 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 like to one of these brilliant butterflies who can test five hypotheses in two minutes? Well, if you back to those psychologists and philosophers, a lot of have said that babies and young children were barely conscious if they were conscious all. And I think just the opposite is true. I think and children are actually more conscious than we are as adults. Now here’s what know about how adult consciousness works. And adults’ attention consciousness look kind of like a spotlight. So what for adults is we decide that something’s relevant or important, we should 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 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 signal makes a little part of our brain much more flexible, more plastic, at learning, and shuts down activity in all the rest of brains. So we have a very focused, purpose-driven kind of attention. we look at babies and young children, we see something different. I think babies and young children seem to have more of a 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 of information 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, and the parts haven’t come on yet. So when we say that babies and 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 all the interesting things that could tell them something just looking at the thing that’s important. That’s the kind attention, the kind of consciousness, that we might expect from butterflies who are designed to learn.
Well if 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 in a new situation that we’ve never been in before — when we fall love with someone new, or when we’re in a new city for the first time. And happens then is not that our consciousness contracts, it expands, that those three days in Paris seem to be full of consciousness and experience than all the months being a walking, talking, faculty meeting-attending zombie back home. by the way, that coffee, that wonderful coffee you’ve drinking downstairs, actually mimics the effect of those baby neurotransmitters. So what’s it like to a baby? It’s like being 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 three o’clock in morning.
(Laughter)
Now it’s good to be a grownup. I don’t want to say much about how wonderful babies are. It’s good to a grownup. We can do things like tie our shoelaces and cross the street ourselves. And it makes sense that we put a of effort into making babies think like adults do. But if what we want is be like those butterflies, to have open-mindedness, open learning, imagination, creativity, innovation, maybe at least some the time we should be getting the adults to start thinking like children.
(Applause)