What is going on in baby’s mind? If you’d asked people this 30 years ago, most people, including psychologists, would have said this baby was irrational, illogical, egocentric — that he couldn’t take perspective of 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 baby’s thinking is like the thinking of the most brilliant scientists.
Let me give just one example of this. One thing that this could be thinking about, that could be going on in his mind, is trying to out what’s going on in the mind of that baby. After all, one of the things that’s hardest for all of us to do is to out what other people are thinking and feeling. And maybe hardest thing of all is to figure out that what other people and feel isn’t actually exactly like what we think and feel. Anyone who’s followed politics can to how hard that is for some people to get. We wanted to know if babies young children could understand this really profound thing about other people. Now the question is: How we ask them? Babies, after all, can’t talk, and if ask 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 actually ask the question?
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Well it turns out that secret was broccoli. What we did — Betty Rapacholi, who was one of my students, and I — actually to give the babies two bowls of food: one bowl of broccoli and one bowl of delicious goldfish crackers. Now all of the babies, even in Berkley, like the and don’t like the raw broccoli. (Laughter) But then what Betty was to take a little taste of food from each bowl. And she would act 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 and other sane person. But half the time, what she do is take a little bit of the broccoli 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. tasted the crackers. Eww, yuck.” So she’d act as what she wanted was just the opposite of what the wanted. We did this with 15 and 18 month-old babies. And then she would simply her hand out and say, “Can you give me some?”
So the question is: would the baby give her, what they liked or what she liked? And the thing was that 18 month-old babies, just barely walking and talking, give her the crackers if she liked the crackers, they would give her the broccoli if she liked broccoli. On the other hand, 15 month-olds would stare at her for a long time if acted as if 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 really remarkable things about this. first one is that these little 18 month-old babies have already discovered this really profound fact human nature, that we don’t always want the same thing. And what’s more, they felt that should actually do things to help other people get what they wanted.
Even more remarkably though, the fact 15 month-olds didn’t do 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 children both know more learn more than we ever would have thought. And this is just one hundreds and hundreds of studies over the last 20 years that’s actually demonstrated it.
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The you might ask though is: Why do children learn so much? And how it possible for them to learn so much in a short time? I mean, after all, if you look at babies superficially, they pretty useless. And actually in many ways, they’re worse useless, because we have to put so much time energy into just keeping them alive. But if we turn evolution for an answer to this puzzle of why we spend much time taking care of useless babies, it turns out that there’s actually an answer. If we look many, many different species of animals, not just us primates, but also including other mammals, birds, even marsupials like and wombats, it turns out that there’s a relationship how long a childhood a species has and how big their are compared to their bodies and how smart and they are.
And sort of the posterbirds for this are the birds up there. On one side is a New Caledonian crow. And crows other corvidae, ravens, rooks and so forth, are incredibly smart birds. They’re smart as chimpanzees in some respects. And this is a bird on cover of science who’s learned how to use a tool get food. On the other hand, we have our the domestic chicken. And chickens and ducks and geese and are basically as dumb as dumps. So they’re very, good at pecking for grain, and they’re not much good at doing else. Well it turns out that the babies, the New crow babies, are fledglings. They depend on their moms to drop worms in little open mouths for as long as two years, which is really long time in the life of a bird. Whereas the are actually mature within a couple of months. So childhood is the reason why the crows up on the cover of Science and the chickens end up in the pot.
There’s something about that long childhood that seems be connected to knowledge and learning. Well what kind of explanation could have for 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 pecking grain in one environment. Other creatures, like the crows, aren’t very good at anything in particular, but they’re extremely good at learning about of different environments.
And of course, we human beings are out on the end of the distribution like the crows. We have brains 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 our babies 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 still popping worms into those little open mouths.
All right, why we see this correlation? Well an idea is that strategy, that learning strategy, is an extremely powerful, great strategy for on in the world, but it has one big disadvantage. And one big disadvantage is that, until you actually do all learning, you’re going 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 actually show up. And the way the evolutions seems have solved that problem is with a kind of of labor. So the idea is that we have this early when we’re completely protected. We don’t have to do anything. All have to do is learn. And then as adults, we take all those things that we learned when we were babies and and actually put them to work to do things there in the world.
So one 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 protected sky guys who just have to go out and learn and have good ideas, 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 thinking about it is instead of thinking of babies children as being like defective grownups, we should think about them as a different developmental stage of the same species — kind of like caterpillars and butterflies — that they’re actually the brilliant butterflies who are flitting around the garden and exploring, and we’re the caterpillars are inching along our narrow, grownup, adult path.
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If this is true, if babies are designed to learn — and this evolutionary story say children are for learning, that’s what they’re for — we might that they would have really powerful learning mechanisms. And fact, the baby’s brain seems to be the most powerful learning on the planet. But real computers are actually getting to be a lot better. there’s been a revolution in our understanding of machine recently. And it all depends on the ideas of this guy, the Reverend Thomas Bayes, who was statistician and mathematician in the 18th century. And essentially what did was to provide a mathematical way using probability theory to characterize, describe, way that scientists find out about the world. So what 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. Then they test that new hypothesis and so and so forth. And what Bayes showed was a way that you could do that. And that mathematics is at the core of the best learning programs that we have now. And some 10 years ago, I suggested that might be doing the same thing.
So if you want to know what’s going on underneath beautiful brown eyes, I think it actually looks something like this. This is Reverend Bayes’s notebook. So think those babies are actually making complicated calculations with conditional probabilities they’re revising to figure out how the world works. All right, now that seem like an even taller order to actually demonstrate. Because after all, you ask even grownups about statistics, they look extremely stupid. How it be that children are doing statistics?
So to test this we used a machine that we have the Blicket Detector. This is a box that lights up and plays when you put some things on it and not others. And using this very simple machine, lab and others have done dozens of studies showing just how good are at learning about the world. Let me mention just one we did with Tumar Kushner, my student. If I showed you this detector, you would be likely think to begin with that the way to make the go would be to put a block on top of the detector. actually, this detector works in a bit of a strange way. Because if you a block over the top of the detector, something you wouldn’t think of to begin with, the detector will actually two out 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 hypothesis actually stronger evidence. It 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 evidence, and we just asked them to make it go. sure enough, the four year-olds used the evidence to wave the object top of the detector.
Now there are two things that are really interesting about this. The first is, again, remember, these are 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 other interesting thing is that they’re using that evidence to to an idea, get to a hypothesis about the world, that seems very unlikely to begin with. And studies we’ve just been doing in my lab, similar studies, we’ve show that year-olds are actually better at finding out an unlikely than adults are when we give them exactly the same task. in these circumstances, the children are using statistics to find out about world, but 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 a 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 did was use our Blicket Detectors. And what she did was children that yellow ones made it go and red didn’t, and then she showed them an anomaly. And what you’ll is that this little boy will go through five hypotheses the space of two minutes.
(Video) Boy: How about this? Same as the side.
Alison Gopnik: Okay, so his first hypothesis has just falsified.
(Laughter)
Boy: This one lighted up, and this one nothing.
AG: Okay, he’s got experimental notebook out.
Boy: What’s making this light up. (Laughter) I don’t know.
AG: Every scientist will that expression of despair.
(Laughter)
Boy: Oh, it’s because this needs to be this, and this needs to be like this.
AG: Okay, 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 only to here, not here. Oh, the bottom of this box 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 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 is a particularly — that is particularly adorable and articulate little boy, but what Cristine 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 series 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 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 of them have that babies and young children were barely conscious if were conscious at all. And I think just the is true. I think babies and children are actually conscious than we are as adults. Now here’s what know about how adult consciousness works. And adults’ attention and consciousness look kind of like a spotlight. what happens 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 extremely bright and vivid, and everything else sort of goes dark. And even know something about the way the brain does this.
So what happens when we pay attention is the prefrontal cortex, the sort of executive part of our brains, a signal that makes a little part of our brain more flexible, more plastic, better at learning, and shuts activity in all the rest of our brains. So we have 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 consciousness a spotlight of consciousness. So babies and young children very bad 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 neurotransmitters that are really good at inducing learning and plasticity, and inhibitory parts haven’t come on yet. So when we say that babies and young children bad at paying attention, what we really mean is that they’re bad at not attention. So they’re bad at getting rid of all interesting 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 might expect from those butterflies who are designed to learn.
Well if want to think about a way of getting a of that kind of baby consciousness as adults, I think the best is think about cases where we’re put in a situation that we’ve never been in before — when we in love with someone new, or when we’re in new city for the first time. And what happens is not that our consciousness contracts, it expands, so that those three days Paris seem to be more full of consciousness and experience than all months of being a walking, talking, faculty meeting-attending zombie back home. by the 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 time after you’ve had three double-espressos. (Laughter) That’s a way to be, but it 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 how wonderful babies are. It’s good to be a grownup. We can do things like our shoelaces and cross the street by ourselves. And it sense that we put a lot of effort into making babies think adults do. But if what we want is to be like butterflies, to have open-mindedness, open learning, imagination, creativity, innovation, at least some of the time we should be getting the adults to start thinking more children.
(Applause)