What is going on in this baby’s mind? you’d asked people this 30 years ago, most people, including psychologists, have said that this baby was irrational, illogical, egocentric — that couldn’t take the perspective of another person or understand cause and effect. In the 20 years, developmental science has completely overturned that picture. So some ways, we think that this baby’s thinking is like the thinking of the most scientists.
Let me give you just one example of this. One thing that baby could be thinking about, that could be going on in his mind, is to figure out what’s going on in the mind of that other baby. After all, of the things that’s hardest for all of us to is to figure out what other people are thinking feeling. And maybe the hardest thing of all is figure out that what other people think and feel isn’t actually exactly like what think and feel. Anyone who’s followed politics can testify to how hard that is for some people get. We wanted to know if babies and young children understand this really profound thing about other people. Now the question is: How could ask them? Babies, after all, can’t talk, and if ask 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 my students, and I — was actually to give the babies two of food: one bowl of raw broccoli and one bowl of delicious crackers. Now all of the babies, even in Berkley, the crackers and don’t like the raw broccoli. (Laughter) then what Betty did was to take a little taste food from each bowl. And she would act as if she liked it or she didn’t. So half time, she acted as if she liked the crackers and didn’t like the — just like a baby and any other sane person. But the time, what she would do is take a little bit of the and go, “Mmmmm, broccoli. I tasted the broccoli. Mmmmm.” And then she would take a little of the crackers, and she’d go, “Eww, yuck, crackers. I the 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 would simply put her hand out and say, “Can you give some?”
So the question is: What would the baby give her, what liked or what she liked? And the remarkable thing was 18 month-old babies, just barely walking and talking, would give her 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 she liked the broccoli, like they couldn’t figure this out. then after they stared for a long time, they would just give the crackers, what they thought everybody must like. So there are two really things about this. The first one is that these 18 month-old babies have already discovered this really profound 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 other people what they wanted.
Even more remarkably though, the fact that 15 month-olds didn’t do this suggests that 18 month-olds had learned this deep, profound fact about human nature in the three months when they were 15 months old. So children both know more and learn more than we would have thought. And this is just one of hundreds and hundreds of 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 in such a short time? I mean, after all, if you look babies 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 to evolution for an answer to this puzzle of we 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, also including other mammals, birds, even marsupials like kangaroos wombats, it turns out that there’s a relationship between how long a childhood a species has and how their brains are compared to their bodies and how smart and flexible they are.
And sort of posterbirds for this idea are the birds up there. On side is a New Caledonian crow. And crows and other corvidae, ravens, rooks and so forth, incredibly smart birds. They’re as smart as chimpanzees in some respects. And is a bird on the cover of science who’s how to use a tool to get food. On the 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 at pecking for grain, and they’re not much good at anything else. Well it turns out that the babies, the New crow babies, are fledglings. They depend on their moms to drop worms in their little open mouths as long as two years, which is a really long time in the life of bird. Whereas the chickens are actually mature within a couple of months. So childhood the reason why the crows end up on the cover of Science and the chickens up in the soup pot.
There’s something about that long childhood that seems be connected to knowledge and learning. Well what kind of explanation could we for this? Well some animals, like the chicken, seem to be beautifully suited to just one thing very well. So they seem to beautifully suited to pecking grain in one environment. Other creatures, like crows, aren’t very good at doing anything in particular, but they’re extremely good learning about laws of different environments.
And of course, human beings are way out on the end of the distribution like the crows. We bigger 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 to cover the world and even go to outer space. And our babies children are dependent on us for much longer than babies of any other species. My son is 23. (Laughter) And at least until they’re 23, we’re still those worms into those little open mouths.
All right, why would we see this correlation? Well an is that that strategy, that learning strategy, is an extremely powerful, great strategy for getting in the world, but it has one big disadvantage. that one big disadvantage is that, until you actually do that learning, you’re going to be helpless. So you don’t want to have the charging at you and be saying to yourself, “A slingshot or a spear might work. Which would actually be better?” You want to know all that before mastodons actually show up. And the way the evolutions seems to have solved that problem is with kind of division of labor. So the idea is that have this early period when we’re completely protected. We don’t have to do anything. All we to do is learn. And then as adults, we can take all those things that we learned we were babies and children and actually put them to work to do things out there in world.
So one way of thinking about it is that babies and young are like the research and development division of the human species. So they’re the protected blue sky guys just have to go out and learn and have ideas, and we’re production and marketing. We have to all those ideas that we learned when we were and actually put them to use. Another way of thinking about it is of thinking of babies and children as being like defective grownups, we should about them as being a different developmental stage of same species — kind of like caterpillars and butterflies — except that they’re actually the brilliant who are flitting around the garden and exploring, and we’re the caterpillars are inching along our narrow, grownup, adult path.
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If this true, if these babies are designed to learn — and this story would say children are for learning, that’s what they’re for — we 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 actually to be a lot better. And there’s been a revolution in our understanding of machine learning recently. it all depends on the ideas of this guy, the Reverend Thomas Bayes, who a statistician and mathematician in the 18th century. And essentially what did was to provide a mathematical way using probability theory to characterize, describe, the that scientists find out about the world. So what scientists do is have a hypothesis that 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 and on and so forth. And what Bayes showed was a mathematical way that you could do that. 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 doing the same thing.
So if you want to what’s going on underneath those beautiful brown eyes, I think it actually looks something 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 world works. All right, now that might seem like even taller order to actually demonstrate. Because after all, if you ask even grownups about statistics, look extremely stupid. How could it be that children are doing statistics?
So to test this we a machine that we have called the Blicket Detector. This a box that lights up and plays music when you put some things on it and others. And using this very simple machine, my lab and others have done dozens of studies showing just good babies are at learning about the world. Let me just one that we did with Tumar Kushner, my student. If showed you this detector, you would be likely to think to begin with that the way make the detector go would be to put a block top of the detector. But actually, this detector works in a of a strange way. Because if you wave a over the top of the detector, something you wouldn’t ever think of to with, the detector will actually activate two out of three times. Whereas, if you do likely thing, put the block on the detector, it will activate two out of six times. So the unlikely hypothesis actually stronger evidence. It looks as if the waving is a more effective strategy the other strategy. So we did just this; we gave four year-olds this pattern of evidence, and we asked them to make it go. And sure enough, the four year-olds used the evidence to wave object on top of the detector.
Now there are two that are really interesting about this. The 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 conditional probability measure. And the other interesting thing is that they’re using 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 my lab, studies, we’ve show that four year-olds are actually better at finding an unlikely hypothesis than adults are when we give them exactly same task. So in these circumstances, the children are using statistics to out about the world, but after all, scientists also do experiments, and we wanted to see children are doing experiments. When children do experiments we call “getting into everything” or else “playing.”
And there’s been bunch of interesting studies recently that have shown 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 was show that yellow ones made it go and red ones didn’t, and then she them an anomaly. And what you’ll see is that this little boy will go five hypotheses in the space of two minutes.
(Video) Boy: How about this? as the other side.
Alison Gopnik: Okay, so his first hypothesis has just been falsified.
(Laughter)
Boy: one lighted up, and this one nothing.
AG: Okay, he’s got his experimental notebook out.
Boy: What’s making this up. (Laughter) I don’t know.
AG: Every scientist will recognize that 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 it 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 and two this one to make it light up.
AG: Okay,there’s his hypothesis.
Now that is a particularly — that is a particularly adorable and articulate little boy, but Cristine discovered is this is actually quite typical. If you look at the way play, when you ask them to explain something, what they really is do a series of experiments. This is actually pretty typical four year-olds.
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Well, what’s it like to this 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 to those psychologists and philosophers, a lot of them have said babies and young children were barely conscious if they were conscious at all. I think just the opposite is true. I think and children are actually more conscious than we are as adults. Now here’s we know about how adult consciousness works. And adults’ attention and consciousness kind of like a spotlight. So what happens for adults is decide that something’s relevant or important, we should pay attention to it. Our consciousness of that that we’re attending to becomes extremely bright and vivid, and everything else sort goes dark. And we even know something about the way the does this.
So what happens when we pay attention is the prefrontal cortex, the sort of executive part of our brains, sends a signal that makes a little of our brain much more flexible, more plastic, better learning, and shuts down activity in all the rest of brains. So we have a very focused, purpose-driven kind attention. If we look at babies and young children, we see something very different. think babies and young children seem to have more of lantern of consciousness than a spotlight of consciousness. So babies and children are very bad at narrowing down to just one thing. But they’re very at taking in lots of information from lots of sources at once. And if you actually look in brains, you see that they’re flooded with these neurotransmitters that really good at inducing learning and plasticity, and the inhibitory parts haven’t come on yet. So when say that babies and young children are bad at paying attention, what we mean is that they’re bad at not paying attention. they’re bad at getting rid of all the interesting things that could tell them something and just at the thing that’s important. That’s the kind of attention, the kind of consciousness, that we expect from those butterflies who are designed to learn.
Well if we to think about a way of getting a taste of kind of baby consciousness as adults, I think the best thing is think cases where we’re put in a new situation that we’ve never been in before — when we fall in with someone new, or when we’re in a new city for the time. And what happens then is not that our consciousness contracts, it expands, so that three days in Paris seem to be more full consciousness and experience than all the months of being a walking, talking, faculty meeting-attending zombie back home. And 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 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 way to be, it 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 things like tie our shoelaces and cross the street by ourselves. And makes sense that 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 least some of the we should be getting the adults to start thinking like children.
(Applause)