What is on in this baby’s mind? If you’d asked people this 30 years ago, people, including psychologists, would have said that this baby irrational, illogical, egocentric — that he couldn’t take the of another person or understand cause and effect. In last 20 years, developmental science has completely overturned that picture. So in some ways, we think that this baby’s is like the thinking of the most brilliant scientists.
Let me give you just example of this. One thing that this baby could be thinking about, that be going on in his mind, is trying to figure out what’s on in the mind of that other baby. After all, one of the things that’s for all of us to do is to figure out what people are thinking and feeling. And maybe the hardest thing of all is to figure out that other people think and feel isn’t actually exactly like what we think and feel. Anyone who’s followed 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 you what he thinks, what you’ll get is a beautiful stream consciousness monologue about ponies and birthdays and things like that. So how we actually ask them the question?
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Well turns out that the secret was broccoli. What we — Betty Rapacholi, who was one of my students, and I — actually to give the babies two bowls of food: one bowl of raw broccoli and bowl of delicious goldfish crackers. Now all of the babies, even in Berkley, like the crackers don’t like the raw broccoli. (Laughter) But then what Betty did was to take a little taste of from each bowl. And she would act as if she liked it or she didn’t. half the time, she acted as if she liked the crackers and didn’t like the broccoli — just a baby and any other sane person. But half time, what she would do is take a little bit of the broccoli go, “Mmmmm, broccoli. I tasted the broccoli. Mmmmm.” And then she would a little bit of the crackers, and she’d go, “Eww, yuck, crackers. I the crackers. Eww, yuck.” So she’d act as if what she wanted was just the opposite what the babies wanted. We did this with 15 and 18 month-old babies. And then she 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 that 18 month-old babies, just barely walking and talking, give her the crackers if she liked the crackers, but would give her the broccoli if she liked the broccoli. On the other hand, 15 month-olds stare at her for a long time if she acted if she liked the broccoli, like they couldn’t figure this out. But then after stared for a long time, they would just give her the crackers, what they thought must like. So there are two really remarkable things about this. first one is that these little 18 month-old babies have already this really profound fact about human nature, that we don’t want the same thing. And what’s more, they felt they should actually do things to help other people get what they wanted.
Even more remarkably though, fact that 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 when they were 15 old. So children both know more and learn more than we ever would thought. And this is just one of hundreds and of studies over the last 20 years that’s actually it.
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The question you might ask though is: do children learn so much? And how is it possible for them to learn so much in a short time? I mean, after all, if you at babies superficially, they seem pretty useless. And actually in many ways, they’re worse than useless, we have to put so much time and energy into keeping them alive. But if we turn to evolution for an answer to this puzzle why we spend so much time taking care of useless babies, it out that there’s actually an answer. If we look across many, many different species of animals, just us primates, but also including other mammals, birds, even marsupials kangaroos and wombats, it turns out that there’s a between how long a childhood a species has and how their brains are compared to their bodies and how smart flexible they are.
And sort of the posterbirds for idea are the birds up there. On one side is a New crow. And crows and other corvidae, ravens, rooks and so forth, incredibly smart birds. They’re as smart as chimpanzees in some respects. And this is a bird the cover of science who’s learned how to use a tool to food. On the other hand, we have our friend domestic chicken. And chickens and ducks and geese and are 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 turns out that the 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 the life of a bird. Whereas the chickens are actually mature a couple of months. So childhood is the reason why the crows end on the cover of Science and the chickens end up in the pot.
There’s something about that long childhood that seems be connected to knowledge and learning. Well what kind of explanation we have for this? Well some animals, like the chicken, seem to be beautifully to doing just one thing very well. So they seem to be beautifully to pecking grain in one environment. Other creatures, like the crows, aren’t very good doing anything in particular, but they’re extremely good at learning about laws different environments.
And of course, we human beings are way out the end of the distribution like the crows. We bigger brains relative to our bodies by far than any animal. We’re smarter, we’re more flexible, we can learn more, we survive in different environments, we migrated to cover the world and even go to outer space. our babies and children are dependent on us for much longer the babies of any other species. My son is 23. (Laughter) 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 is that, until you actually do all learning, you’re going to be helpless. So you don’t want to have the charging at you and be saying to yourself, “A or maybe a spear might work. Which would actually be better?” You to know all that before the mastodons actually show up. And the way the evolutions seems to have solved problem is with a kind of division of labor. So the is that we have this early period when we’re completely protected. We don’t to do anything. All we have to do is learn. then as adults, we can take all those things that we learned when we were babies children and actually put them to work to do out there in the world.
So one way of about it is that babies and young children are 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 have good ideas, we’re production and marketing. We have to take all ideas that we learned when we were children and actually them to use. Another way of thinking about it is instead of thinking of babies and children as like defective grownups, we should think about them as a different developmental stage of the same species — kind like caterpillars and butterflies — except that they’re actually the 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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If this is true, if babies are designed to learn — and this evolutionary would say children are for learning, that’s what they’re for — we might expect that they would really powerful learning mechanisms. And in fact, the baby’s seems to be the most powerful learning computer on the planet. But real are actually getting 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 was a statistician mathematician in the 18th century. And essentially what Bayes did was to provide mathematical way using probability theory to characterize, describe, the way that scientists find out about world. So what scientists do is they have a hypothesis that they might be likely to start with. They go out and test it against the evidence. The evidence them change that hypothesis. Then they test that new hypothesis and so on and so forth. And what showed was a mathematical way that you could do that. And that mathematics is at the core the best machine learning programs that we have now. And 10 years ago, I suggested that babies might be the same thing.
So if you want to know what’s going on underneath those beautiful brown eyes, think it actually looks something like this. This is Bayes’s notebook. So I think those babies are actually making complicated calculations 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 children are doing statistics?
So test this we used a machine that we have called the Blicket Detector. This is a box lights up and plays music when you put some things on it not others. And using this very simple machine, my lab and others have done dozens studies showing just how good babies are at learning the world. Let me mention just one that we 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 to put a block on 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 to begin with, the detector will actually activate two out of times. Whereas, if you do the likely thing, put the block the detector, it will only activate two out of six times. the unlikely hypothesis actually has stronger evidence. It looks as if the waving a more effective strategy than the other strategy. So did just this; we gave four year-olds this pattern evidence, and we just asked them to make it go. And sure enough, the four year-olds the evidence to wave the object on top of the detector.
Now there are things that are really interesting about this. The first is, again, remember, these are four year-olds. They’re just learning how to count. unconsciously, they’re doing these quite complicated calculations that will them a conditional probability measure. And the other interesting thing is they’re using that evidence to get to an idea, to a hypothesis about the world, that seems very unlikely to 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 an unlikely hypothesis than adults are we give them exactly the same task. So in these circumstances, the children are using statistics find out about the world, but after all, scientists also do experiments, and we wanted to if children are doing experiments. When children do experiments we call it “getting into everything” or “playing.”
And there’s been a bunch of interesting studies recently have shown this playing around is really a kind experimental research program. Here’s one from Cristine Legare’s lab. What Cristine did was our Blicket Detectors. And what she did was show 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 little boy will go five hypotheses in the space of two minutes.
(Video) Boy: How about this? Same the other side.
Alison Gopnik: Okay, so his first hypothesis has just falsified.
(Laughter)
Boy: This one lighted up, and this one nothing.
AG: Okay, he’s got experimental 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 this needs to be like this, and this needs be like this.
AG: Okay, hypothesis two.
Boy: That’s why. Oh.
(Laughter)
AG: Now this is next idea. He told the experimenter to do this, to try putting it onto the other location. Not working either.
Boy: Oh, the light goes only to here, not here. Oh, the bottom of this box has electricity in here, this doesn’t have electricity.
AG: Okay, that’s a fourth hypothesis.
Boy: It’s up. So when you put four. So you put four on this one to make it up and two on this one to make it 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 is actually quite typical. If look at the way children play, when you ask them to explain something, 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 like to be this kind creature? What’s it like to be one of these brilliant butterflies who test five hypotheses in two minutes? Well, if you go back to those psychologists and philosophers, a lot them have said that babies and young children were conscious if they were conscious at all. And I think just the opposite true. I think babies and children are actually more conscious we are as adults. Now here’s what we know about adult consciousness works. And adults’ attention and consciousness look of like a spotlight. So what happens for adults is decide that something’s relevant or important, we should pay attention it. Our consciousness of that thing that we’re attending to extremely bright and vivid, and everything else sort of goes dark. And we even know something about way the brain does this.
So what happens when we attention is that the prefrontal cortex, the sort of executive part of our brains, sends 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 have a very focused, purpose-driven kind of attention. we look at babies and young children, we see something very different. I think babies young children seem to have more of a lantern of consciousness than spotlight of consciousness. So babies and young children are bad at narrowing down to just one thing. But they’re good at taking in lots of information from lots of different sources at once. And if actually look in their brains, you see that they’re flooded with these neurotransmitters are really good at inducing learning and plasticity, and the parts haven’t come on yet. So when we say that babies young children are bad at paying attention, what we really is that they’re bad at not paying attention. So they’re at getting rid of all the interesting things that could tell them and just looking at the thing that’s important. That’s the kind of attention, the kind of consciousness, we might expect from those butterflies who are designed to learn.
Well we want to think about a way of getting a of that 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 the first time. And what happens then is not our consciousness contracts, it expands, so that those three days in Paris seem to more full of consciousness and experience than all the months of being a walking, talking, meeting-attending zombie back home. And by the way, that coffee, that wonderful you’ve been drinking downstairs, actually mimics the effect of baby neurotransmitters. So what’s it like to be a baby? It’s being in love in Paris for the first time after you’ve had three double-espressos. (Laughter) That’s a way to be, but it does tend to leave you waking crying at three o’clock in the morning.
(Laughter)
Now it’s good to be a grownup. I don’t to say too much about how wonderful babies are. It’s good to a grownup. We can do things like tie our and cross the street by ourselves. And it makes sense we put a lot of effort into making babies think like adults do. But what we want is to be like those butterflies, to open-mindedness, open learning, imagination, creativity, innovation, maybe at least some of time we should be getting the adults to start thinking like children.
(Applause)