What is going on in baby’s mind? If you’d asked people this 30 years ago, most people, including psychologists, would have said that this was irrational, illogical, egocentric — that he couldn’t take the of another person or understand cause and effect. In the last 20 years, developmental science has overturned that picture. So in some ways, we think this baby’s thinking is like the thinking of the brilliant scientists.
Let me give you just one example of this. One thing that this baby could be about, that could be going on in his mind, is trying to figure what’s going on in the mind of that other baby. all, one of the things that’s hardest for all of us to do to figure out what other people are thinking and feeling. And maybe the hardest thing of all is figure out that what other people think and feel isn’t actually exactly what we think and feel. Anyone who’s followed politics testify to how hard that is for some people to get. We wanted know if babies and young children could understand this 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 a beautiful stream of consciousness monologue about ponies and birthdays and things like that. So do we actually ask them the question?
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Well turns out that the secret was broccoli. What we did — Betty Rapacholi, who was one my students, and I — was actually 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 from each bowl. And she act as if she liked it or she didn’t. So the time, she acted as if she liked the crackers and didn’t like the broccoli — like a baby and any other sane person. But half the time, what she would is take a little bit of the broccoli and go, “Mmmmm, broccoli. I tasted broccoli. Mmmmm.” And then she would take a little bit of 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 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 is: What would the baby give her, what they liked or what she liked? And the remarkable was that 18 month-old babies, just barely walking and talking, would give her crackers if she liked the crackers, but they would give her broccoli if she liked the broccoli. On the other hand, 15 month-olds would stare at her for a time if she acted as if she liked the broccoli, they couldn’t figure this out. But then after they stared a 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 is that these little 18 month-old have already discovered this really profound fact about human nature, that don’t always want the same thing. And what’s more, they felt that they should actually do things help other people get what they wanted.
Even more though, the fact that 15 month-olds didn’t do this suggests that these 18 month-olds had learned this deep, fact about human nature in the three months from they were 15 months old. So children both know more and learn than we ever would have thought. And this is one 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 do children learn much? And how is it possible for them to learn so much in such 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 and energy into just them alive. But if we turn to evolution for an to this puzzle of why we spend so much time care of useless babies, it turns out that there’s actually answer. If we look across many, many different species of animals, not just us primates, but also other 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 brains are compared to their bodies and how smart flexible they are.
And sort of the posterbirds for this are the birds up there. On one side is New Caledonian crow. And crows and other corvidae, ravens, and so forth, are incredibly smart birds. They’re as smart chimpanzees in some respects. And this is a bird on the cover of who’s learned how to use a tool to get food. On the other hand, we have our friend domestic chicken. And chickens and ducks and geese and turkeys are basically as dumb dumps. So they’re very, very good at pecking for grain, and they’re much good at doing anything else. Well it turns out that the babies, New Caledonian crow babies, are fledglings. They depend on their moms drop worms in their 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 the crows end up on the cover of Science and chickens end up in the soup pot.
There’s something about that long childhood that seems to be connected knowledge and learning. Well what kind of explanation could have for this? Well some animals, like the chicken, to be beautifully suited to doing just one thing well. So they seem to be beautifully suited to pecking in one environment. Other creatures, like the crows, aren’t good at doing anything in particular, but they’re extremely at learning about laws of different environments.
And of course, 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 learn more, survive in more different environments, we migrated to cover the world even go to outer 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 little open mouths.
All right, why would we see this correlation? Well idea is that that strategy, that learning strategy, is an powerful, great strategy for getting on in the world, but has one big disadvantage. And that one big disadvantage that, until you actually do all that learning, you’re to be helpless. So you don’t want to have the mastodon charging you and be saying to yourself, “A slingshot or maybe a spear might work. would actually be better?” You want to know all before the mastodons actually show up. And the way the evolutions seems to have solved that problem with a kind of division of labor. So the idea is we have this early period when we’re completely protected. We don’t have do anything. All we have to do is learn. And then adults, we can take all those things that we learned when we were babies and and actually put them to work to do things out in the world.
So one way of thinking about it that babies and young children are like the research and development division of human species. So they’re the protected blue sky guys who just have to go out and and have good ideas, and we’re production and marketing. We have to take those ideas that we learned when we were children actually put them to use. Another way of thinking about it instead of thinking of babies and children as being like grownups, we should think about them as being a developmental stage of the same species — kind of like caterpillars and butterflies — except that they’re actually brilliant butterflies who are flitting around the garden and exploring, we’re the caterpillars who are inching along our narrow, grownup, adult path.
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this is true, if these babies are designed to — and this evolutionary story would say children are learning, that’s what they’re for — we might expect that they have really powerful learning mechanisms. And in fact, the baby’s seems to be the most powerful learning computer on the planet. real computers are actually getting to be a lot better. there’s been a revolution in our understanding of machine learning recently. And it all depends on the ideas this guy, the Reverend Thomas Bayes, who was a statistician and mathematician in 18th century. And essentially what Bayes did was to provide a mathematical way using probability to characterize, describe, the way that scientists find out about the world. So what scientists is they have a hypothesis that they think might be to start with. They go out and test it against evidence. The evidence makes them change that hypothesis. Then they test that new hypothesis and so on so forth. And what Bayes showed was a mathematical way that you could that. And that mathematics is at the core of the best machine learning programs that we have now. 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 something like this. This Reverend Bayes’s notebook. So I think those babies are actually complicated calculations 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 demonstrate. Because 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 that we have called the Blicket Detector. This is box that lights up and plays music when you put some things on it and not others. And this very simple machine, my lab and others have done dozens of showing just how good babies are at learning about world. Let me mention just one that we did Tumar Kushner, my student. If I showed you this detector, would be likely to think to begin with that the way to make the go would be to put a block on top of detector. But actually, this detector works in a bit of a strange way. Because if wave a block over the top of the detector, something you wouldn’t think of to begin with, the detector will actually activate two out three times. Whereas, if you do the likely thing, put block on the detector, it will only activate two of six times. So the unlikely hypothesis actually has stronger evidence. It looks if the waving is a more effective strategy than the strategy. So we did just this; we gave four year-olds this pattern of evidence, and we just asked 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 that are really 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 a conditional probability measure. And the other interesting thing is that they’re using that to get to an idea, get to a hypothesis about the world, that seems very to begin with. And in studies we’ve just been doing in my lab, studies, we’ve show that four year-olds are actually better at finding out unlikely hypothesis than adults are when we give them the same task. So in these circumstances, the children are statistics to find out about the world, but after all, scientists also do experiments, and wanted to see if children are doing experiments. When do experiments we call it “getting into everything” or else “playing.”
And there’s been a bunch of 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 was show children that yellow ones made it go and red ones didn’t, and she showed them an anomaly. And what you’ll see that this little boy will go through five hypotheses in space of two minutes.
(Video) Boy: How about this? Same as the other side.
Alison Gopnik: Okay, so first hypothesis has just been falsified.
(Laughter)
Boy: This one up, and this one nothing.
AG: Okay, he’s got his experimental 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 be like this.
AG: Okay, two.
Boy: That’s why. Oh.
(Laughter)
AG: Now this is his next idea. 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 box has 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 four on this one to make it light up and on this one to make it light up.
AG: Okay,there’s his fifth hypothesis.
Now that is particularly — that is a particularly adorable and articulate little boy, but what discovered is this is actually quite typical. If you look at way children play, when you ask them to explain something, what they really do is do a of experiments. This is actually pretty typical of four year-olds.
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Well, what’s it like to this kind of creature? What’s it like to be of these brilliant butterflies who can test five hypotheses in two minutes? Well, if you go back those psychologists and philosophers, a lot of them have said that and young children were barely conscious if they were at all. And I think just the opposite is true. I babies and children are actually more conscious than we as adults. Now here’s what we know about how adult consciousness works. And adults’ and consciousness look kind of like a spotlight. So what happens adults is we decide that something’s relevant or important, we should pay attention to it. Our of that thing that we’re attending to becomes extremely bright vivid, and everything else sort of goes dark. And we know something about the way the brain does this.
So what when we pay attention is that the prefrontal cortex, the sort of executive of our brains, sends a signal that makes a little part of our much more flexible, more plastic, better at learning, and down activity in all the rest of our brains. we have a 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 consciousness than a spotlight of consciousness. So babies and young children are very bad at narrowing down to one thing. But they’re very good at taking in lots of information lots of different sources at once. And if you actually in their brains, you see that they’re flooded with these neurotransmitters that are really good at inducing learning plasticity, and the inhibitory parts haven’t come on yet. So we say that babies and young children are bad at paying attention, what we really mean that they’re bad at not paying attention. So they’re bad at getting rid of all the interesting that could tell them something and just looking at thing that’s important. That’s the kind of attention, the of consciousness, that we might expect from those butterflies who are to learn.
Well if we want to think about a way of a taste of that kind of baby consciousness as adults, I think the best thing think about cases where we’re put in a new that we’ve never been in before — when we in love with someone 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 seem to be more full of consciousness and than all the months of being a walking, talking, meeting-attending zombie back home. And by the way, that coffee, wonderful coffee you’ve been drinking downstairs, actually mimics the effect those baby neurotransmitters. So what’s it like to be baby? It’s like being in love in Paris for first time after you’ve had three double-espressos. (Laughter) That’s a fantastic to be, but it does tend to leave you up crying at three o’clock in the morning.
(Laughter)
Now it’s to be a grownup. I don’t want to say too much how wonderful babies are. It’s good to be a grownup. We do things like tie our shoelaces and cross the street by ourselves. And it makes sense we put a lot of effort into making babies think like do. But if what we want is to be like those butterflies, have open-mindedness, open learning, imagination, creativity, innovation, maybe at some of the time we should be getting the adults to thinking more like children.
(Applause)