What is going on in this baby’s mind? If you’d people this 30 years ago, most people, including psychologists, have said that this baby was irrational, illogical, egocentric — he couldn’t take the perspective of another person or cause and effect. In the last 20 years, developmental science has overturned that picture. So in some ways, we think that this baby’s thinking is like the of the most brilliant scientists.
Let me give you 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 other baby. all, one of the things that’s hardest for all us to do is to figure out what other people thinking and feeling. And maybe the hardest thing of is to figure out that what other people think feel isn’t actually exactly like what we think and feel. Anyone who’s followed politics can testify to hard that is for some people to get. We wanted to know if babies and young children could this really profound thing about other people. Now the question is: How could ask them? Babies, after all, can’t talk, and if you ask a three year-old to tell what he thinks, what you’ll get is a beautiful stream of consciousness about ponies and birthdays and things like that. So 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 of food: one bowl of raw broccoli and one of delicious goldfish crackers. Now all of the babies, even in Berkley, the crackers and don’t like the raw broccoli. (Laughter) But then Betty did was to take a little taste of from each bowl. And she would act as if liked it or she didn’t. So half the time, she acted as if she the crackers and didn’t like the broccoli — just like baby and any other sane person. But half the time, what would do is take a little bit of the broccoli and go, “Mmmmm, broccoli. I tasted broccoli. Mmmmm.” And then she would take a little of the crackers, and she’d go, “Eww, yuck, crackers. tasted the crackers. Eww, yuck.” So she’d act as if she wanted was just the opposite of what the babies wanted. We did this with 15 18 month-old babies. And then she would simply put her out and say, “Can you give me some?”
So question is: What would the baby give her, what they liked or what she liked? And remarkable thing was that 18 month-old babies, just barely and talking, would give her the crackers if she liked the crackers, but would give 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 she the broccoli, like they couldn’t figure this out. But then after stared for a long time, they would just give her crackers, what they thought everybody must like. So there are two really remarkable things about this. The one is that these little 18 month-old babies have already discovered 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 things to help 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 deep, profound fact about human nature in the three months from they were 15 months old. So children both know more and learn more than we ever have thought. And this is just one of hundreds and of studies over the last 20 years that’s actually demonstrated it.
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question you might ask though is: Why do children so 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. And actually in ways, they’re worse than useless, because we have to put so much time and energy into just them alive. But if we turn to evolution for an answer to this puzzle of we spend so much time taking care of useless babies, it turns out that there’s actually answer. If we look across many, many different species animals, not just us primates, but also including other mammals, birds, even marsupials like kangaroos and wombats, it turns that there’s a relationship between how long a childhood a species has how big their brains are compared to their bodies and how and flexible they are.
And sort of the posterbirds this idea are the birds up there. On one side is a New Caledonian crow. And crows and corvidae, ravens, rooks and so forth, are incredibly smart birds. They’re as smart as chimpanzees some respects. And this is a bird on the cover of science who’s learned how to a tool to get food. On the other hand, we have friend the domestic chicken. And chickens and ducks and geese and turkeys are basically as as dumps. So they’re very, very good at pecking for grain, and they’re not good at doing anything else. Well it turns out that babies, the New Caledonian crow babies, are fledglings. They depend on their moms to worms in their little open mouths for as long as two years, which is a really long time the life of a bird. Whereas the chickens are actually mature within a of months. So childhood is the reason why the end up on the cover of Science and the chickens up in the soup pot.
There’s something about that long childhood seems to be connected to knowledge and learning. Well what of explanation could we have for this? Well some animals, like the chicken, seem to be suited to doing just one thing 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 out 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, can learn more, we survive in more different environments, we migrated to cover the world and even to outer space. And our babies and children are dependent on us for much longer than babies of any other species. My son is 23. (Laughter) at least until they’re 23, we’re still popping those into those little open mouths.
All right, why would we see correlation? Well an idea is that that strategy, that strategy, is an extremely powerful, great strategy for getting on the world, but it has one big disadvantage. And that one big disadvantage 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 and saying to yourself, “A slingshot or maybe a spear work. Which would actually be better?” You want to all that before the mastodons actually show up. And the the evolutions seems to have solved that problem is with a of division 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 take those things that we learned when we were babies and and actually put them to work to do things out there in 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 blue sky guys who just have to go out 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 them use. Another way of thinking about it is instead of thinking of babies and as being like defective grownups, we should think about them as being a different stage of the same species — kind of like caterpillars and butterflies — that they’re actually the brilliant butterflies who are flitting around the and exploring, and we’re the caterpillars who are inching along our narrow, grownup, path.
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If this is true, if these babies are designed learn — and this evolutionary story would say children are learning, that’s what they’re for — we might expect that they would have powerful learning mechanisms. And in fact, the baby’s brain seems be the most powerful learning computer on the planet. But real computers actually getting to be a lot better. And there’s been a in our understanding of machine learning recently. And it depends on the ideas of this guy, the Reverend Bayes, who was a statistician and mathematician in the 18th century. And essentially Bayes did was to provide a mathematical way using probability to characterize, describe, the way that scientists find out about world. So what scientists do is they have a hypothesis that 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 and on and so forth. And what Bayes showed was mathematical way that you could do that. And that is at the core of the best machine learning that we have now. And some 10 years ago, I suggested that babies might be the same thing.
So if you want to know what’s on underneath those beautiful brown eyes, I think it actually looks like this. This is Reverend Bayes’s notebook. So I think those babies are actually complicated calculations with conditional probabilities that they’re revising to figure out how world works. All right, now that might seem like an even taller to actually demonstrate. Because after all, if you ask grownups about statistics, they look extremely stupid. How could it be children are doing statistics?
So to test this we used a that we have called the Blicket Detector. This is a box that lights up and music when you put some things on it and others. And using this very simple machine, my lab and others done dozens of studies showing just how good babies are at learning the world. Let me mention just one that we did with Tumar Kushner, 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 on top of detector. But actually, this detector works in a bit a strange way. Because if you wave a block the top of the detector, something you wouldn’t ever of to begin with, the detector will actually activate out of three times. Whereas, if you do the likely thing, put the block on detector, it will only activate two out of six times. So unlikely hypothesis actually has stronger evidence. It looks as the waving is a more effective strategy than the other strategy. So did just this; we gave four year-olds this pattern of evidence, and we asked them to make it go. And sure enough, the year-olds used the evidence to wave the object on top of the detector.
Now are two things that are really interesting about this. The first is, again, remember, these are four year-olds. They’re just learning how count. But unconsciously, they’re doing these quite complicated calculations will give them a conditional probability measure. And the other interesting thing is they’re using that evidence to get to an idea, get to a hypothesis about the world, seems very unlikely to begin with. And in studies we’ve just been doing my lab, similar studies, we’ve show that four year-olds actually better at finding out an unlikely hypothesis than adults when we give them exactly the same task. So these circumstances, the children are using statistics to find out about world, but after all, scientists also do experiments, and wanted to see if children are doing experiments. When children experiments we call it “getting into everything” or else “playing.”
And there’s been a of interesting studies recently that have shown this playing is really a kind of experimental research program. Here’s one Cristine Legare’s lab. What Cristine did was use our Blicket Detectors. And what she was show children that yellow ones made it go and red ones didn’t, and then showed them an anomaly. And what you’ll see is that this boy will go through five hypotheses in the space two minutes.
(Video) Boy: How about this? Same as the side.
Alison Gopnik: Okay, so his first hypothesis has been falsified.
(Laughter)
Boy: This one lighted up, and one nothing.
AG: Okay, he’s got his experimental notebook out.
Boy: What’s this light up. (Laughter) I don’t know.
AG: Every scientist will recognize expression of despair.
(Laughter)
Boy: Oh, it’s because this needs to be like this, this 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 this, to try putting it out onto the other location. Not working either.
Boy: Oh, because the light goes to here, not here. Oh, the bottom of this box has 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 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 a particularly adorable and articulate little boy, but what Cristine discovered is this actually quite typical. If you look at the way children play, when ask them to explain something, what they really do is do 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 brilliant butterflies who can five hypotheses in two minutes? Well, if you go back those psychologists and philosophers, a lot of them have said that babies and children were barely conscious if they were conscious at all. And I just the opposite is true. I think babies and are actually more conscious than we are as adults. here’s what we know about how adult consciousness works. And adults’ attention and look kind of like a spotlight. So what happens for is we decide that something’s relevant or important, we should pay attention to it. Our consciousness that thing that we’re attending to becomes extremely bright and vivid, and everything else sort of dark. And we even know something about the way the brain 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 a very focused, purpose-driven kind of attention. If we look babies and young children, we see something very different. think babies and 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 of different sources at once. And if you actually in their brains, you see that they’re flooded with these neurotransmitters that are good at inducing learning and plasticity, and the inhibitory parts haven’t come yet. So when we say that babies and young children are bad at 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 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 new situation that we’ve never been in before — we fall in love with someone new, or when we’re in a new for the first time. And what happens then is not that our consciousness contracts, it expands, that those three days in Paris seem to be more full of consciousness and experience all the months of being a walking, talking, faculty meeting-attending zombie home. And by the way, that coffee, that wonderful coffee you’ve been drinking downstairs, actually 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 after you’ve had three double-espressos. (Laughter) That’s a fantastic way to be, but does tend to leave you waking up crying at o’clock in the morning.
(Laughter)
Now it’s good to be grownup. I don’t want to say too much about how babies are. It’s good to be a grownup. We can do things like tie our shoelaces and cross street by ourselves. And it makes sense that we put a lot of effort into making think like adults do. But if what we want is to like those butterflies, to have open-mindedness, open learning, imagination, creativity, innovation, maybe at least some of the time we be getting the adults to start thinking more like children.
(Applause)