What going on in this baby’s mind? If you’d asked this 30 years ago, most people, including psychologists, would said that this baby was irrational, illogical, egocentric — he couldn’t take the perspective of another person or understand cause and effect. In last 20 years, developmental science has completely overturned that picture. in some ways, we think that this baby’s thinking is the thinking of the most brilliant scientists.
Let me give you just one example of this. One that this baby could be thinking about, that could be going on his mind, is trying to figure out what’s going in the mind of that other baby. After all, one the things that’s hardest for all of us to do to figure out what other people are thinking and feeling. And maybe the thing of all is to figure out that what other think and feel isn’t actually exactly like what we and feel. Anyone who’s followed politics can testify to how 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 could we them? Babies, after all, can’t talk, and if you ask three year-old to tell you what he thinks, what you’ll get is beautiful stream of consciousness monologue about ponies and birthdays 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 one of my students, and I — was actually 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 did was to take little taste of food from each bowl. And she would act if she liked it or she didn’t. So half the time, she acted if she liked the crackers and didn’t like the broccoli — like a baby and any other sane person. But half time, what she would do is take a little bit the broccoli and go, “Mmmmm, broccoli. I tasted the broccoli. Mmmmm.” then she would take a little bit of the crackers, and she’d go, “Eww, yuck, crackers. I the crackers. Eww, yuck.” So she’d act as if she wanted was just the opposite of what the babies wanted. We this with 15 and 18 month-old babies. And then she simply put her hand out and say, “Can you me some?”
So the question is: What would the baby 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 give her the broccoli if she liked broccoli. On the other hand, 15 month-olds would stare at her for long time if she acted as if she liked the broccoli, they couldn’t figure this out. But then after they stared for long time, they would just give her the crackers, what they thought everybody must like. there are two really remarkable things about this. The first one that these little 18 month-old babies have already discovered this really fact about human nature, that we don’t always want the thing. And what’s more, they felt that they should actually do things to help 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, profound fact about nature in the three months from when they were 15 old. So children both know more and learn more than we ever would thought. And this is just one of hundreds and hundreds 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 much? And how is it possible for them to learn so much in such a short time? mean, after all, if you look at babies superficially, seem pretty useless. And actually in many ways, they’re than useless, because we have to put so much and energy into just keeping them alive. But if we turn to evolution 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, different species of animals, not just us primates, but including other mammals, birds, even marsupials like kangaroos and wombats, it turns out there’s a relationship between how long a childhood a species has and how big brains are compared to their bodies and how smart and flexible they are.
And sort the posterbirds for this idea are the birds up there. one side is a New Caledonian crow. And crows other corvidae, ravens, rooks and so forth, are incredibly birds. They’re as smart as chimpanzees in some respects. And this a bird on the cover of science who’s learned how to use a to get food. On the other hand, we have friend the domestic chicken. And chickens and ducks and geese and turkeys are basically as dumb as dumps. 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 Caledonian crow babies, fledglings. They depend on their moms 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 is reason why the crows end up on the cover of Science and the end up in the soup pot.
There’s something about that long childhood seems 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 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 about laws of different environments.
And course, we human beings are way out on the end of 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 more, we survive in more different environments, we migrated to cover the world and go to outer space. And our babies and children are dependent on us for longer than the babies of any other species. My is 23. (Laughter) And at least until they’re 23, we’re popping those worms into those little open mouths.
All right, why would see this 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 one disadvantage is that, until you 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 slingshot or maybe spear might work. Which would actually be better?” You want to know all that the mastodons actually show up. And the way the evolutions seems have solved that 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 then as adults, we take all those things that we learned when we were babies and children and put them to work to do things out there in the world.
So one way of about it is that babies and young children are 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 take all those ideas that we learned when we were and actually put them to use. Another way of about it is instead of thinking of babies and children as being like defective grownups, we think about them as being a different developmental stage of the same species — kind of like and butterflies — except that they’re actually the brilliant butterflies who are around the garden and exploring, and we’re the caterpillars who are 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 for learning, that’s they’re for — we might expect that they would have really powerful learning mechanisms. And fact, the baby’s brain seems to be the most learning computer on the planet. But real computers are 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 was a statistician and in the 18th century. And essentially what Bayes did to provide a mathematical way using probability theory to characterize, describe, the way that scientists find out the world. So what scientists do is they have a hypothesis that they think be likely to start with. They go out and test against the evidence. The evidence makes them change that hypothesis. Then test that new hypothesis and so on and so forth. And what Bayes showed was mathematical way that you could do that. And that mathematics at the core of the best machine learning programs we have now. And some 10 years ago, I that babies might be doing the same thing.
So if you want to know what’s on underneath those beautiful brown eyes, I think it looks something like this. This is Reverend Bayes’s notebook. So I think those babies are actually making complicated with conditional probabilities that they’re revising to figure out how the works. All right, now that might seem like an even taller order to actually demonstrate. after all, if you ask even grownups about statistics, look extremely stupid. How could it be that children doing statistics?
So to test this we used a machine that we have called the Blicket Detector. is a box that lights up and plays music you put some things on it and not others. And this very simple machine, my lab and others have done dozens of studies showing how good babies are at learning about the world. Let me just 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 to the detector go would be to put a block top of the detector. But actually, this detector works a bit of a strange way. Because if you wave a block over the top of the detector, you wouldn’t ever think of to begin with, the detector will actually activate out of three times. Whereas, if you do the thing, put the block on the detector, it will activate two out of six times. So the unlikely hypothesis has stronger evidence. It looks as if the waving a more 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 go. And sure enough, the four year-olds used the evidence wave the object on top of the detector.
Now are two things that are really interesting about this. first one is, again, remember, these are four year-olds. They’re learning how to count. But unconsciously, they’re doing these quite complicated calculations that will give them a conditional measure. And the other interesting thing is that they’re using that evidence to to an idea, get to a hypothesis about the world, seems very unlikely to begin 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 hypothesis adults are when we give them exactly the same task. So in these circumstances, the children are using statistics find out about the world, but after all, scientists do experiments, and we wanted to see if children doing experiments. When children do experiments we call it “getting into everything” else “playing.”
And there’s been a bunch of interesting studies recently that have this playing around is really a kind of experimental program. Here’s one from Cristine Legare’s lab. What Cristine was use our Blicket Detectors. And what she did show children that yellow ones made it go and ones didn’t, and then she showed them an anomaly. And what you’ll see is that 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 falsified.
(Laughter)
Boy: This one lighted up, and this one nothing.
AG: Okay, he’s his experimental 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 this needs to be like this, and this needs be like this.
AG: Okay, hypothesis two.
Boy: That’s why. Oh.
(Laughter)
AG: Now this is next idea. He told the experimenter to do this, to try putting out onto the other location. Not working either.
Boy: Oh, the light goes only to here, not here. Oh, the bottom of this box has in here, but this doesn’t have electricity.
AG: Okay, that’s a fourth hypothesis.
Boy: It’s lighting up. So you put four. So you put four on this one to make it light up two on this one to make it light up.
AG: Okay,there’s his fifth hypothesis.
Now is a particularly — that is a particularly adorable and articulate little boy, what Cristine discovered is this is actually quite typical. you look at the way children play, when you ask them explain something, what they really 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 brilliant butterflies who can test five in two minutes? Well, if you go back to those psychologists philosophers, a lot of them have said that babies young children were barely conscious if they were conscious at all. And I think just the is true. I think babies and children are actually more than we are as adults. Now here’s what we know about how consciousness works. And adults’ attention and consciousness look kind like a spotlight. So what happens for adults is decide that something’s relevant or important, we should pay 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 about the way the brain does this.
So what happens when we pay attention that the prefrontal cortex, the sort of executive part our brains, sends a signal that makes a little part our brain much more flexible, more plastic, better at learning, shuts down activity in all the rest of our brains. we have a very focused, purpose-driven kind of attention. If we look at and young children, we see something very different. I think babies and young children seem to have of a lantern of consciousness 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 of different at once. And if you actually look in their brains, you see 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 we say that and young children are bad at paying attention, what we really mean is 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 at 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 we to think about a way of getting a taste of that kind of baby consciousness as adults, I the best thing is think about cases where we’re put in a new situation that we’ve never in before — when we fall in love with someone new, or when we’re in a new city the first time. And what happens then is not that consciousness contracts, it expands, so that those three days in Paris seem to be more of consciousness and experience than all the months of being walking, talking, faculty meeting-attending zombie back home. And by the way, that coffee, that wonderful coffee you’ve been downstairs, actually mimics the effect of those baby neurotransmitters. 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 it does tend to leave waking up crying at three o’clock in the morning.
(Laughter)
Now it’s good to be a grownup. I don’t want say too much about how wonderful babies are. It’s good to be a grownup. We can do like tie our shoelaces and cross the street by ourselves. it makes sense that we put a lot of effort into making babies like adults do. But if what we want is to be like those butterflies, have open-mindedness, open learning, imagination, creativity, innovation, maybe at least some of time we should be getting the adults to start more like children.
(Applause)