What is going on in this baby’s mind? If you’d people this 30 years ago, most people, including psychologists, would said that this baby was irrational, illogical, egocentric — that couldn’t take the perspective of another person or understand cause effect. In the last 20 years, developmental science has completely overturned that picture. in some ways, we think that this baby’s thinking like the thinking of the most brilliant scientists.
Let me you just one example of this. One thing that this could be thinking about, that could be going on in mind, is trying to figure out what’s going on in the mind that other baby. After all, one of the things that’s for all of us to do is to figure what other people are thinking and feeling. And maybe hardest thing of all is to figure out that what other think and feel isn’t actually exactly like what we think and feel. who’s followed politics can testify to how hard that is for some people to get. We wanted know if babies and young children could understand this really thing about other people. Now the question is: How we 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 monologue about ponies birthdays and things like that. So how do we actually them the question?
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Well it turns out that the secret broccoli. What we did — Betty Rapacholi, who was one of my students, and I — was to give the babies two bowls of food: one of raw broccoli and one bowl of delicious goldfish crackers. all of the babies, even in Berkley, like the and don’t like the raw broccoli. (Laughter) But then Betty did was to take a little taste of food each bowl. And she would act as if she it or she didn’t. So half the time, she acted as if she liked the crackers and didn’t the broccoli — just like a baby and any other sane person. But half the time, she would do is take a little bit of the broccoli go, “Mmmmm, broccoli. I tasted the broccoli. Mmmmm.” And then would take a little bit of the crackers, and she’d go, “Eww, yuck, crackers. I tasted crackers. Eww, yuck.” So she’d act as if what she wanted just the opposite of what the babies wanted. We did this 15 and 18 month-old babies. And then she would simply her hand out and say, “Can you give me some?”
So question is: What would the baby give her, what liked or what she liked? And the remarkable thing was that 18 month-old babies, barely walking and talking, would give her the crackers if liked the crackers, but they would give her the if she liked the broccoli. On the other hand, 15 month-olds would at her for a long time if she acted as if liked the broccoli, like they couldn’t figure this out. But then after stared for a long time, they would just give the crackers, what they thought everybody must like. So are two really remarkable things about this. The first one that these little 18 month-old babies have already discovered really profound fact about human nature, that we don’t always the same thing. And what’s more, they felt that they should actually do things to other people get what they wanted.
Even more remarkably though, the fact that 15 month-olds didn’t do this that these 18 month-olds had learned this deep, profound fact about human nature in three months from when they were 15 months old. So children both know and learn more than we ever would 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 learn so in such a short time? I mean, after all, if you look at superficially, they seem pretty useless. And actually in many ways, they’re worse useless, because we have to put so much time and into just keeping them alive. But if we turn evolution for an answer to this puzzle of why we spend so time taking care of useless babies, it turns out there’s actually an answer. If we look across many, many different of animals, not just us primates, but also including mammals, birds, even marsupials like kangaroos and wombats, it turns out that there’s a relationship how long a childhood a species has and how big their brains are to their bodies and how smart and flexible they are.
And sort of the posterbirds for 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 chimpanzees in some respects. And this is a bird on the cover of science who’s learned how use a tool to get food. On the other hand, we have our friend domestic chicken. And chickens and ducks and geese and turkeys basically as dumb as dumps. So they’re very, very good at pecking for grain, they’re not much good at doing anything else. Well it turns out that babies, the New Caledonian crow babies, are fledglings. They depend on moms to drop worms in their little open mouths for as as two years, which is a really long time in the life of a bird. Whereas chickens are actually mature within a couple of months. So 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 seems to be connected to knowledge and learning. Well kind of explanation could we have for this? Well some animals, the chicken, seem to be beautifully suited to doing just one thing very well. they seem to be beautifully suited to pecking grain in environment. Other creatures, like the crows, aren’t very good at doing anything in particular, but they’re extremely at learning about laws of different environments.
And of course, we human beings are out on the end of the distribution like the crows. We have bigger brains relative our bodies by far than any other animal. We’re smarter, we’re flexible, we can learn more, we survive in more environments, we migrated to cover the world and even go 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 strategy, is an extremely powerful, great strategy for getting on in world, but it has one big disadvantage. And that one big disadvantage is that, until you actually all that learning, you’re going to be helpless. So you don’t want to the mastodon charging at you and be saying to yourself, “A or maybe a spear might work. Which would actually be better?” want to know all that before the mastodons actually up. And the way the evolutions seems to have solved that problem with a kind of division of labor. So the idea is that we have this early period we’re completely 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 to to do things out there in the world.
So 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 blue guys who just have to go out and learn and 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 thinking about is instead of thinking of babies and children as being defective grownups, we should think about them as being a different developmental stage the same species — kind of like caterpillars and butterflies — except they’re actually the brilliant butterflies who are flitting around the and exploring, and we’re the caterpillars who are inching our 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 for learning, that’s what they’re for — we might expect that they would have powerful learning mechanisms. And in fact, the baby’s brain to be the most powerful learning computer on the planet. But real computers are actually getting to be a better. And there’s been a revolution in our understanding of machine learning recently. And it depends on the ideas of this guy, the Reverend Thomas Bayes, who was a statistician mathematician in the 18th century. And essentially what Bayes did was to a mathematical way using probability theory to characterize, describe, the way that find out about the world. So what scientists do is they have hypothesis that they think might be likely to start with. go out and test it against the evidence. The evidence makes them that hypothesis. Then they test that new hypothesis and so on and forth. And what Bayes showed was a 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 what’s going on underneath those beautiful brown eyes, I think actually looks something like this. This is Reverend Bayes’s notebook. So I those babies are actually making complicated calculations with conditional probabilities that they’re revising to out how the world works. All right, now that might seem like even taller order to actually demonstrate. Because after all, if you even grownups about statistics, they look extremely stupid. How could be that children are doing statistics?
So to test this we a machine that we have called the Blicket Detector. This is a that lights up and plays music when you put things on it and not others. And using this very simple machine, my lab and others done dozens of studies showing just how good babies are at learning about the world. me mention just one that we did with Tumar Kushner, my student. If I showed you detector, you would be likely to think to begin that 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 block over the top of the detector, something you wouldn’t ever think of begin with, the detector will actually activate two out of times. Whereas, if you do the likely thing, put the on the detector, it will only activate two out of six times. the unlikely hypothesis actually has stronger evidence. It looks if the waving is a more effective strategy than the other strategy. we did just this; we gave four year-olds this pattern of evidence, and we just them to make it go. And sure enough, the four year-olds used the evidence wave the object on top of the detector.
Now there are two things that are interesting about this. The first one is, again, remember, are four year-olds. They’re just learning how to count. unconsciously, they’re doing these quite complicated calculations that will give them conditional probability measure. And the other interesting thing is that they’re using that evidence get to an idea, get to a hypothesis about the world, that very unlikely to begin with. And in studies we’ve just doing in my lab, similar studies, we’ve show that year-olds are actually better at finding out an unlikely hypothesis than adults are when give them exactly the same task. So in these circumstances, the children are using statistics to find out the world, but after all, scientists also do experiments, and we wanted to see if children doing experiments. When children do experiments we call it “getting into everything” or else “playing.”
And there’s been bunch 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 did was show that yellow ones made it go and red ones didn’t, then she showed them an anomaly. And what you’ll is 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, so his hypothesis has just been falsified.
(Laughter)
Boy: This one 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 will recognize that expression of despair.
(Laughter)
Boy: Oh, it’s because this needs to like this, and this needs to be like this.
AG: Okay, two.
Boy: That’s why. Oh.
(Laughter)
AG: Now this is his idea. He told the experimenter to do this, to try putting it onto the other location. Not working either.
Boy: Oh, because the goes only to here, not here. Oh, the bottom of this has electricity in here, but this doesn’t have electricity.
AG: Okay, that’s fourth hypothesis.
Boy: It’s lighting up. So when you four. So you put four on this one to make it light up and on this one to make it light up.
AG: Okay,there’s fifth hypothesis.
Now that is a particularly — that a particularly adorable and articulate little boy, but what discovered is this is actually quite typical. If you look at the way children play, you ask them to explain something, what they really do is do a series of experiments. This actually pretty typical of four year-olds.
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Well, what’s it to be this kind of creature? What’s it like to be one of these brilliant butterflies who test five hypotheses in two minutes? Well, if you go to those psychologists and philosophers, a lot of them have said that babies and young were barely conscious if they were conscious at all. And I think just opposite 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 a spotlight. So what happens for adults is we decide that something’s relevant or important, we pay attention to it. Our consciousness of that thing that we’re attending to becomes extremely and vivid, and everything else sort of goes dark. And we even know something about the way brain does this.
So what happens when we pay is that the prefrontal cortex, the sort of executive of our brains, sends a signal that makes a part of our brain much more flexible, more plastic, at learning, and shuts down activity in all the rest our brains. So we have a very focused, purpose-driven of attention. If we look at babies and young children, we see something very different. think babies and young children seem to have more a lantern of consciousness than a spotlight of consciousness. So babies young children are very bad at narrowing down to just thing. But they’re very good at taking in lots of information lots of different sources at once. And if you actually look in their brains, you see that they’re with these neurotransmitters that are really good at inducing learning and plasticity, the inhibitory parts haven’t come on yet. So when we say that babies and young are bad at paying attention, what we really mean that they’re bad at not paying attention. So they’re at getting rid of all the interesting things that could tell something and just looking at the thing that’s important. That’s kind of attention, the kind of consciousness, that we might expect from those butterflies are designed to learn.
Well if we want to think 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 in a new situation that we’ve never been in before — we fall in love with someone new, or when we’re in a city for the first time. And what happens then is not that our consciousness contracts, expands, so that those three days in Paris seem to be more full of and experience than all the months of being a walking, talking, faculty meeting-attending zombie home. And by the way, that coffee, that wonderful you’ve been drinking downstairs, actually mimics the effect of those baby neurotransmitters. So what’s it like to be baby? It’s like being in love in Paris for the first time after you’ve three double-espressos. (Laughter) That’s a fantastic way to be, but it does tend to leave you up crying at three o’clock in the morning.
(Laughter)
Now it’s good to be a grownup. I don’t want to too much about 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 makes sense that we put a of effort into making babies think like adults do. But if we want is to be like those butterflies, to open-mindedness, open learning, imagination, creativity, innovation, maybe at least some of the time we should be the adults to start thinking more like children.
(Applause)