What is on in this baby’s mind? If you’d asked people 30 years 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 thinking of the most brilliant scientists.
Let me give you one example of this. One thing that this baby could be thinking about, that could be going on his mind, is trying to figure out what’s going on in the mind of that baby. After all, one of the things that’s hardest for of us to do is to figure out what other people are thinking and feeling. And the hardest thing of all is to figure out that what people think and feel isn’t actually exactly like what we think feel. Anyone who’s followed politics can testify to how hard is for some people to get. We wanted to know babies and young children could understand this really profound about other people. Now the question is: How could we 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 ponies and birthdays and things like that. So how do we actually ask them question?
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Well it turns out that the was broccoli. What we did — Betty Rapacholi, who was one of my students, and — was actually to give the babies two bowls of food: one bowl of broccoli and one bowl of delicious goldfish crackers. Now of the babies, even in Berkley, like the crackers and don’t like the raw broccoli. (Laughter) But what Betty did was to take a little taste of food from each bowl. she would act as if she liked it or she didn’t. half the time, she acted as if she liked crackers and didn’t like the broccoli — just like baby and any other sane person. But half the time, she would do is take a little bit of the 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. tasted the crackers. Eww, yuck.” So she’d act as if what she wanted was the opposite of what the babies wanted. We did this with 15 18 month-old babies. And then she would simply put her hand out say, “Can you give me some?”
So the question is: What would the baby give her, what liked or what she liked? And the remarkable thing was that 18 month-old babies, just barely and talking, would give her the crackers if she liked the crackers, but they would her the broccoli if she liked the broccoli. On other hand, 15 month-olds would stare at her for a long time if she acted as if liked the broccoli, like they couldn’t figure this out. But then after they stared for long time, they would just give her the crackers, they thought everybody must like. So there are two 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 thing. And what’s more, they felt that they should actually do to help other people get what they wanted.
Even more remarkably though, fact that 15 month-olds didn’t do this suggests that 18 month-olds had learned this deep, profound fact about human 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 this is just of hundreds and hundreds of studies over the last 20 years that’s actually it.
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The question you might ask though is: Why children learn so much? And how is it possible them to learn so much in such a short time? I mean, after all, if look at babies superficially, they seem pretty useless. And actually many ways, they’re worse than useless, because we have to put much time and energy into just keeping them alive. But if we turn evolution for an answer to this puzzle of why spend so much time taking care of useless babies, turns out that there’s actually an answer. If we look many, many different species of animals, not just us primates, but also other mammals, birds, even marsupials like kangaroos and wombats, turns out that there’s a relationship between how long a childhood a has and how big their brains are compared to bodies and how smart and flexible they are.
And sort of posterbirds for this idea are the birds up there. On one side a New Caledonian crow. And crows and other corvidae, ravens, rooks so forth, are incredibly smart birds. They’re as smart as in some respects. And this is a bird on cover of science who’s learned how to use a to get food. On the other hand, we have our friend the domestic chicken. And chickens and and geese and turkeys are basically as dumb as dumps. So they’re very, very good at for grain, and they’re not much good at doing anything else. Well it turns that the babies, the New Caledonian crow babies, are fledglings. They on their moms to drop worms in their little mouths for as long as two years, which is a really long time the life of a bird. Whereas the chickens are actually within a couple of months. So childhood is the reason why crows end up on the cover of Science and the chickens end up in the pot.
There’s something about that long childhood that seems to be to knowledge and learning. Well what kind of explanation could we for this? Well some animals, like the chicken, seem be beautifully suited 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 very at doing anything in particular, but they’re extremely good learning about laws of different environments.
And of course, we human beings are way on the end of the distribution like the crows. have bigger brains relative to our bodies by far any other animal. We’re smarter, we’re more flexible, we can learn more, we survive in more different environments, 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. My son 23. (Laughter) And at least until they’re 23, we’re still popping those worms into those little mouths.
All right, why would we see this correlation? an idea is that that strategy, that learning strategy, an extremely powerful, great strategy for getting on in the world, but it has one disadvantage. And that one big disadvantage is that, until you actually do all that learning, you’re going be helpless. So you don’t want to have the mastodon charging at you be saying to yourself, “A slingshot or maybe a might work. Which would actually be better?” You want know all that before the mastodons actually show up. And the way the evolutions to have solved that problem is with a kind of of labor. So the idea is that we have this early period when we’re protected. We don’t have to do anything. All we have do is learn. And then as adults, we can all those things that we learned when we were babies and children and actually put them work to do things out there in the world.
So one way of about it is that babies and young children are like the research and division of the human species. So they’re the protected blue guys who just have to go out and learn 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 them to use. way of thinking about it is instead of thinking of babies children as being like defective grownups, we should think about them as being a different developmental of the same species — kind of like caterpillars and — except that they’re actually the brilliant butterflies who flitting around the garden and exploring, and we’re the caterpillars who are inching along 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 are learning, that’s what they’re for — we might expect that they would have really learning mechanisms. And in fact, the baby’s brain seems to be the most learning computer on the planet. But real computers are actually to be a lot better. And there’s been a revolution in understanding of machine learning recently. And it all depends on ideas of this guy, the Reverend Thomas Bayes, who a statistician and mathematician in the 18th century. And what Bayes did was to provide a mathematical way using theory to characterize, describe, the way that scientists find out 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 so on and so forth. And what Bayes showed was a mathematical way you could do that. And that mathematics is at the of the best machine learning programs that we have now. And some 10 years ago, suggested that babies 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 that they’re revising to figure out how world works. All right, now that might seem like even taller order to actually demonstrate. Because after all, if you ask even about statistics, they look extremely stupid. How could it be that are doing statistics?
So to test this we used a machine that have called the Blicket Detector. This is a box that lights up and plays music when you put 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 one that we did with Tumar Kushner, my student. If I showed you detector, you would be likely to think to begin with the 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 wave a block over the top of detector, something you wouldn’t ever think of to begin with, the will actually activate two out of three times. Whereas, if do the likely thing, put the block on the detector, 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 this; we gave four year-olds this pattern of evidence, we just asked them to make it go. And sure enough, the four year-olds used the evidence to the object on top of the detector.
Now there two things that are really interesting about this. The one is, again, remember, these are four year-olds. They’re just learning how 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 that evidence to get to an idea, get to a hypothesis about world, that 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 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, but after all, scientists also do experiments, we wanted to see if children are doing experiments. children do experiments we call it “getting into everything” else “playing.”
And there’s been a bunch of interesting studies recently that shown this playing around is really a kind of experimental research program. Here’s one from Cristine Legare’s lab. Cristine did was use our Blicket Detectors. And what she was show children that yellow ones made it go red ones didn’t, and then she showed them an anomaly. And what you’ll see that this little boy will go through five hypotheses in the of two minutes.
(Video) Boy: How about this? Same as the other side.
Alison Gopnik: Okay, his first hypothesis has just been falsified.
(Laughter)
Boy: This 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 will that expression of despair.
(Laughter)
Boy: Oh, it’s because needs to be like this, and this needs to like this.
AG: Okay, hypothesis two.
Boy: That’s why. Oh.
(Laughter)
AG: Now is his next idea. He told the experimenter to this, to try putting it out onto the other location. working either.
Boy: Oh, because the light goes only to here, not here. Oh, bottom of this box has electricity in here, but doesn’t have electricity.
AG: Okay, that’s a fourth hypothesis.
Boy: It’s lighting up. So when you put four. So put four on this one to make it light up and two on this one to make light up.
AG: Okay,there’s his fifth hypothesis.
Now that is a particularly — that is a adorable and articulate little boy, but what Cristine discovered is this is quite typical. If you 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 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 butterflies who can test five hypotheses in two minutes? Well, you go back to those psychologists and philosophers, a lot of them have that babies and young children were barely conscious if they were conscious at all. And I just the opposite is true. I think babies and children are actually more than we are as adults. Now here’s what we know about how adult consciousness works. adults’ attention and consciousness look kind of like a spotlight. So happens for adults is we decide that something’s relevant or important, we should pay to it. Our consciousness of that thing that we’re to becomes extremely bright and vivid, and everything else of goes dark. And we even know something about the the brain does this.
So what happens when we pay attention that 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 down activity all the rest of our 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 of a lantern of consciousness than a spotlight of consciousness. So and young children are very bad at narrowing down to just thing. But they’re very good at taking in lots of information from lots of different sources at once. if you actually look in their brains, you see they’re flooded with these neurotransmitters that are really good inducing learning and plasticity, and the inhibitory parts haven’t come on yet. 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 of all the things that could tell them something and just looking at the that’s important. That’s the kind of attention, the kind of consciousness, that we might expect from those butterflies are designed to learn.
Well if we want to about a way of getting a taste of that kind of consciousness as adults, I think the best thing is about cases where we’re put in a new situation we’ve never been in before — when we fall in love with 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 to be more full of consciousness and experience than the months of being a walking, talking, faculty meeting-attending zombie home. And by the way, that coffee, that wonderful coffee you’ve been downstairs, actually 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 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 say too much about wonderful babies are. It’s good to be a grownup. We do things like tie our shoelaces and cross the by ourselves. And it makes sense that we put lot of effort into making babies think like adults do. if what we want is to be like those butterflies, to open-mindedness, open learning, imagination, creativity, innovation, maybe at least some of the we should be getting the adults to start thinking more children.
(Applause)