What is going in this baby’s mind? If you’d asked people this 30 years ago, most people, psychologists, would have said that this baby was irrational, illogical, egocentric — that he couldn’t take the of another person or understand cause and effect. In the last 20 years, developmental has completely 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 this. One thing that this baby could be thinking about, that could be going on in mind, is trying to figure out what’s going on in mind of that other baby. After all, one of the things that’s hardest for of us to do is to figure out what other people are thinking and feeling. And maybe hardest thing of all is to figure out that what other people and feel isn’t actually exactly like what we think and feel. Anyone who’s politics can testify to how hard that is for people to get. We wanted to know if babies and young children could understand really profound thing about other people. Now the question is: How could ask 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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it turns out that the secret was broccoli. What we did — Betty Rapacholi, who one of my students, and I — was actually give the babies two bowls of food: one bowl of raw broccoli and one of delicious goldfish crackers. Now all of the babies, in Berkley, like the crackers and don’t like the raw broccoli. (Laughter) But then what did was to take a little taste of food from each bowl. And she would act as she liked it or she didn’t. So half the time, she acted if she liked the crackers and didn’t like the broccoli — like 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 would take a little bit 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. did this with 15 and 18 month-old babies. And then she would simply put hand out and say, “Can you give me some?”
So the question is: What would baby give her, what they liked or what she liked? And the remarkable thing was 18 month-old babies, just barely walking and talking, would her the 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 for a long time if she acted as if she the broccoli, like they couldn’t figure this out. But then after they for a long time, they would just give her the crackers, what thought everybody must like. So there are two really remarkable about this. The first one is that these little 18 month-old babies have already discovered really profound fact about human nature, that we don’t want the same thing. And what’s more, they felt that they should actually do to help other people get what they wanted.
Even remarkably though, the fact that 15 month-olds didn’t do suggests that these 18 month-olds had learned this deep, fact about human nature in the three months from when they 15 months old. So children both know more and more than we ever would have thought. And this is just one hundreds and hundreds of studies over the last 20 years that’s demonstrated it.
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The 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 babies superficially, seem pretty useless. And actually in many ways, they’re worse than useless, because have to put so much time and energy into just keeping alive. But if we turn to evolution for an to this puzzle of why we spend so much time taking of useless babies, it turns out that there’s actually an answer. If we across many, many different species of animals, not just primates, but also including other mammals, birds, even marsupials like kangaroos and wombats, it out that there’s a relationship between how long a childhood species has and how big their brains are compared their bodies and how smart and flexible they are.
And of the posterbirds for this idea are the birds there. On one side is a New Caledonian crow. And crows other corvidae, ravens, rooks and so forth, are incredibly smart birds. They’re as smart as in 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 our friend the domestic chicken. And chickens and ducks geese and turkeys are basically as dumb as dumps. So they’re very, very good at for grain, and they’re not much good at doing else. Well it turns out that the babies, the New crow babies, are fledglings. They depend on their moms to drop in their little open mouths for as long as two years, which is a really long time in life of a bird. Whereas the chickens are actually mature within a couple months. So childhood is the reason why the crows end up on the cover of Science and chickens end up in the soup pot.
There’s something that long childhood that seems to be connected to and learning. Well what kind of explanation could we for this? Well some animals, like the chicken, seem to be suited to doing just one thing very well. So they seem to beautifully suited to pecking 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 different environments.
And course, we human beings are way out on the of the distribution like the crows. We have bigger brains relative to our bodies by than any other animal. We’re smarter, we’re more flexible, we learn more, we survive in more different environments, we migrated to cover the and even go to outer space. And our babies and children are dependent us for much longer than the babies of any other species. My son 23. (Laughter) And at least until they’re 23, we’re popping those worms into those little open mouths.
All right, would we see this correlation? Well an idea is that strategy, that learning strategy, is an extremely powerful, great for getting on in the world, but it has big disadvantage. And that one big disadvantage is that, until you actually do that learning, you’re going to be helpless. So you don’t to have the mastodon charging at you and be to yourself, “A slingshot or maybe a spear might work. would actually be better?” You want to know all that before the actually show up. And the way the evolutions seems have solved that problem is with a 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 have to do learn. And then as adults, we can take all those things that we learned when we babies and children and actually put them to work to do things out there the world.
So one way of thinking about it is that babies and children are like the research and development division of the human species. they’re the protected blue sky guys who just have go out and learn and have good ideas, and we’re production and marketing. We to take all those ideas that we learned when we were children and actually put to use. Another way of thinking about it is instead of thinking of and children as being like defective grownups, we should about them as being a different developmental stage of the same species — 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 who are inching along narrow, grownup, adult path.
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If this is true, if these babies are designed to — and this evolutionary story would say children are for learning, that’s they’re for — we might expect that they would really powerful learning mechanisms. And in fact, the baby’s brain seems to be the most learning computer on the planet. But real computers are actually getting be a lot better. And there’s been a revolution in our of machine learning recently. And it all depends on the of this guy, the Reverend Thomas Bayes, who was a and mathematician in the 18th century. And essentially what Bayes did was to provide a mathematical way probability theory 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 them change that hypothesis. Then test that new hypothesis and so on and so forth. And what Bayes showed a mathematical way that you could do that. And that mathematics is the core of the best machine learning programs that have now. And some 10 years ago, I suggested babies might be doing the same thing.
So if you want to know what’s on underneath those beautiful brown eyes, I think it looks something like this. This is Reverend Bayes’s notebook. So I think those babies are actually making calculations with conditional probabilities that they’re revising to figure how the world works. All right, now that might seem like an even order to actually demonstrate. Because after all, if you even grownups about statistics, they look extremely stupid. How could it be children are doing statistics?
So to test this we used a machine that we have the Blicket Detector. This is a box that lights up plays music when you put some things on it and not others. And using this very simple machine, lab and others have done dozens of studies showing just good babies are at learning about the world. Let mention just one that we did with Tumar Kushner, my student. I showed you this detector, you would be likely to to begin with that the way to make the detector go would be to put block on top of the detector. But actually, this detector works in a bit of a strange way. if you wave a block over the top of the detector, you wouldn’t ever think of to begin with, the will actually activate two out of three times. Whereas, if you do the thing, put the block on the detector, it will only two out 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 asked them to make it go. And sure enough, four year-olds used the evidence to wave the object on of the detector.
Now there are two things that are really interesting about this. first one 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 give them a conditional probability measure. And the other thing is that they’re using that evidence to get to an idea, get to a about the world, that seems very unlikely to begin with. And in we’ve just been doing in my lab, similar studies, we’ve show four year-olds are actually better at finding out an unlikely hypothesis than adults when 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 experiments, and we wanted to see if children are doing experiments. When children do experiments we call “getting into everything” or else “playing.”
And there’s been a of interesting studies recently that have shown this playing around really a kind of experimental research program. Here’s one from Cristine Legare’s lab. 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 she showed them an anomaly. And what you’ll see is that this little boy will through five hypotheses in the space of two minutes.
(Video) Boy: How this? Same as the other side.
Alison Gopnik: Okay, so his first hypothesis just been falsified.
(Laughter)
Boy: This one lighted up, 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 next idea. He told the experimenter do this, to try putting it out onto the location. Not working either.
Boy: Oh, because the light goes only here, not here. Oh, the bottom of this box electricity 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 on one to make it light up.
AG: Okay,there’s his hypothesis.
Now that is a particularly — that is a adorable and articulate little boy, but what Cristine discovered is is actually quite typical. If you look at the children play, when you ask them to explain something, what they really is do a series of experiments. This is actually typical of four 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 test five in two minutes? Well, if you go back to those psychologists and philosophers, lot of them have said that babies and young children were barely conscious if were conscious at all. And I think just the is true. I think babies and children are actually more conscious than we are adults. Now here’s what we know about how adult works. And adults’ attention and consciousness look kind 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 becomes bright and vivid, and everything else sort of goes dark. And we know something about the way the brain does this.
So happens when we pay attention is that the prefrontal cortex, sort of executive part of our brains, sends a signal that makes a little part of our much more flexible, more plastic, better at learning, and shuts down activity in all rest of our brains. So we have a very focused, purpose-driven kind of attention. If we look at and young children, we see something very different. I think babies young children seem to have more of 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 from lots of different sources once. And if you actually look in their brains, see that they’re flooded with these neurotransmitters that are good at inducing learning and plasticity, and the inhibitory 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 bad at getting of all the interesting 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 who are designed to learn.
Well if we want to think about a way of getting a of 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 city for first time. And what happens then is not that consciousness contracts, it expands, so that those three days in Paris seem be more full of consciousness and experience than all 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 neurotransmitters. So what’s it like to be a baby? It’s like being love in Paris for the first time after you’ve had double-espressos. (Laughter) That’s a fantastic way to be, but does tend to leave you waking up crying at three o’clock 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 be a grownup. We can do things like tie shoelaces and cross the street by ourselves. And it makes sense we put a lot of effort into making babies think like adults do. But if we want is to be like those butterflies, to have open-mindedness, open learning, imagination, creativity, innovation, maybe least some of the time we should be getting the adults to start thinking like children.
(Applause)