What going on 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 20 years, developmental science has completely overturned that picture. So some ways, we think that this baby’s thinking is 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 his mind, trying to figure out what’s going on in the mind of other baby. After all, one of the things that’s for all of us to do is to figure out what other people thinking and feeling. And maybe the hardest thing of all is to figure out that what other think and feel isn’t actually exactly like what we and feel. Anyone who’s followed politics can testify to how hard that is for some to get. We wanted to know if babies and young children could this really profound thing about other people. Now the question is: could we ask them? Babies, after all, can’t talk, if you ask a 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 how we actually ask them the question?
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Well it turns out the secret was broccoli. What we did — Betty Rapacholi, was one of my students, and I — was actually give the babies two bowls of food: one bowl of raw broccoli one bowl of delicious goldfish crackers. Now all of the babies, even in Berkley, the crackers and don’t like the raw broccoli. (Laughter) But then what Betty did was take a little taste of food from each bowl. And she would act if she liked it or she didn’t. So half time, she acted as if she liked the crackers and didn’t like broccoli — just like a baby and any other sane person. But half time, what she would do is take a little bit the broccoli and go, “Mmmmm, broccoli. I tasted the broccoli. Mmmmm.” And she 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 what wanted was just the opposite of what the babies wanted. did this with 15 and 18 month-old babies. And she would simply put her hand out and say, “Can give me some?”
So the question is: What would the baby give her, what they liked or she liked? And the remarkable thing was that 18 month-old babies, just barely and talking, would give her the crackers if she the crackers, but they would give her the broccoli if she the broccoli. On the other hand, 15 month-olds would stare her for a long time if she acted as if she the broccoli, like they couldn’t figure this out. But after they stared for a long time, they would give her the crackers, what they thought everybody must like. So there are two remarkable things about this. The first one is that these little 18 month-old babies have already this really profound fact about human nature, that we don’t always want the same thing. And what’s more, they that they should actually do things to help other get what they wanted.
Even more remarkably though, the that 15 month-olds didn’t do this suggests that these 18 month-olds had learned this deep, profound fact about nature in the three months from when they were 15 old. So children both know more and learn more than we ever would have thought. And is just one of hundreds and hundreds of studies over last 20 years that’s actually demonstrated it.
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question you might ask though is: Why do children learn so much? And how is 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 than useless, because we have put so much time and energy into just keeping them alive. But if we turn evolution for an answer to this puzzle of why we spend so much time taking care of babies, it turns out that there’s actually an answer. If look across many, many different species of animals, not us primates, but also including other mammals, birds, even like kangaroos and wombats, it turns out that there’s a between how long a childhood a species has and how big their brains are compared to bodies and how smart and flexible they are.
And sort the posterbirds for this idea are the birds up there. On one side is a New crow. And crows and other corvidae, ravens, rooks and forth, are incredibly smart birds. They’re as smart as in some respects. And this is a bird on the cover science who’s learned how to use a tool to get food. On the other hand, we have friend the 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 the babies, the Caledonian crow babies, are fledglings. They depend on their to drop worms in their little open mouths for as long as two years, which a really long time in the life of a bird. Whereas chickens are actually mature within a couple of months. So childhood is reason why the crows end up on the cover of Science and chickens end up in the soup pot.
There’s something about that long that seems to be connected to knowledge and learning. Well what kind of explanation could have for this? Well some animals, like the chicken, seem to beautifully suited 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 at doing anything particular, but they’re extremely good at learning about laws of environments.
And of course, we human beings are way out on the end of the distribution the crows. We have bigger brains relative to our bodies by 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 and even go to outer space. And our babies and children are dependent us for much longer than the babies of any species. My son is 23. (Laughter) And at least they’re 23, we’re still popping those worms into those open mouths.
All right, why would we see this correlation? Well an is that that strategy, that learning strategy, is an extremely powerful, strategy for getting on in the world, but it has one big disadvantage. And that one disadvantage is that, until you actually do 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 slingshot maybe a spear might work. Which 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 is a kind of division of labor. So the idea is that we have this period when we’re completely protected. We don’t have to do anything. All have to do is learn. And then as adults, we take all those things that we learned when we were babies children and actually put them to work to do things out there in world.
So one way of thinking about it is that babies young children are like the research and development division the 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 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 of babies and children as being like defective grownups, we should think them as being a different developmental stage of the same species — kind of like and butterflies — except that they’re actually the brilliant butterflies who flitting around the garden and exploring, and we’re the caterpillars who inching along our narrow, grownup, adult path.
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this is true, if these babies are designed to learn — this evolutionary story would say children are for learning, that’s they’re for — we might expect that they would have powerful learning mechanisms. And in fact, the baby’s brain seems be the most powerful learning computer on the planet. But real computers actually getting to be a lot better. And there’s been a in our understanding of machine learning recently. And it all depends on the ideas of this guy, Reverend Thomas Bayes, who was a statistician and mathematician in the 18th century. And essentially what did was to provide a mathematical way using probability to characterize, describe, the way that scientists find out about the world. So scientists do is they have a hypothesis that they might be likely to start with. They go out and test it against evidence. The evidence makes them change that hypothesis. Then they test new hypothesis and so on and so forth. And what showed was a mathematical way that you could do that. And that mathematics at the core of 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 on underneath those beautiful brown eyes, I think it actually looks something like this. This is Bayes’s notebook. So I think those babies are actually making complicated calculations with probabilities that they’re revising to figure out how the world works. All right, that might seem like an even taller order to demonstrate. Because after all, if you ask even grownups about statistics, they extremely stupid. How could it be that children are statistics?
So to test this we used a machine that we have called Blicket Detector. This is a box that lights up plays music when you put some things on it and others. And using this very simple machine, my lab others have done dozens of studies showing just how good babies are learning about the world. Let me mention just one that we did with Tumar Kushner, my student. If showed you this detector, you would be likely to to begin with that the way to make the detector go be to put a block on top of the detector. But actually, this detector works a bit of a strange way. Because if you wave a block over top of the detector, something you wouldn’t ever think to begin with, the detector will actually activate two out three times. Whereas, if you do the likely thing, the block on the detector, it will only activate out of six times. So the unlikely hypothesis actually has stronger evidence. 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, we just asked them to make it go. And sure enough, the year-olds used the evidence to wave the object on top the detector.
Now there are two things that are really interesting about this. The first is, again, remember, these are four year-olds. They’re just learning how to count. But unconsciously, they’re doing quite complicated calculations that will give them a conditional probability measure. And the other interesting is that they’re using that evidence to get to an idea, get a hypothesis about the world, that seems very unlikely begin with. And in studies we’ve just been doing in lab, similar studies, we’ve show that four year-olds are actually better at finding out an unlikely hypothesis adults are when we give them exactly the same task. So these circumstances, the children are using statistics to find about the world, but after all, scientists also do experiments, and we to see if children are doing experiments. When children do experiments we call it “getting into everything” else “playing.”
And there’s been a bunch of interesting studies that have shown this playing around is really a kind of experimental 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 she showed them an anomaly. And you’ll see is that this little boy will go through five hypotheses in the of two minutes.
(Video) Boy: How about this? Same the other side.
Alison Gopnik: Okay, so his first has just been falsified.
(Laughter)
Boy: This one lighted up, and this nothing.
AG: Okay, he’s got his experimental notebook out.
Boy: What’s this light up. (Laughter) I don’t know.
AG: Every scientist recognize that expression of despair.
(Laughter)
Boy: Oh, it’s because needs to be like this, and this needs to like this.
AG: Okay, hypothesis two.
Boy: That’s why. Oh.
(Laughter)
AG: Now this is his next idea. told the experimenter to do this, to try putting it out onto the other location. Not either.
Boy: Oh, because the light goes only to here, not here. Oh, the bottom this box has electricity in here, but this doesn’t electricity.
AG: Okay, that’s a fourth hypothesis.
Boy: It’s lighting up. So when put four. So you put four on this one to make it light up and two on this to make it light up.
AG: Okay,there’s his fifth 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 way children play, you ask them to explain something, what they really do is do series of experiments. This is actually pretty typical of four year-olds.
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Well, what’s like to be this kind of creature? What’s it like to 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 conscious if they were conscious at all. And I just the opposite is true. I think babies and children actually more conscious than we are as adults. Now here’s we know about how adult consciousness works. And adults’ attention consciousness look kind of like a spotlight. So what happens for adults we decide that something’s relevant or important, we should pay attention it. Our consciousness of that thing that we’re attending becomes extremely bright and vivid, and everything else sort goes dark. And we even know something about the way the brain does this.
So happens when we pay attention is that the prefrontal cortex, the of executive part of our brains, sends a signal that a little part of our brain much more flexible, more plastic, better at learning, and down activity in all the rest of our brains. So have a very focused, purpose-driven kind of attention. If 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 information from lots of different sources at once. And you actually look in their brains, you see that they’re flooded with these that are really good at inducing learning and plasticity, the inhibitory parts haven’t come on yet. So when we say babies and young children are bad at paying attention, what we really mean is that they’re at not paying attention. So they’re bad at getting of all the interesting things that could tell them something and just looking 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 want to think about a way of getting a taste of that kind of baby 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 first time. And what happens then is not that our contracts, it expands, so that those three days in Paris seem to be more of consciousness and experience than all the months of being a walking, talking, faculty meeting-attending zombie back home. by the way, that coffee, that wonderful coffee you’ve drinking downstairs, actually mimics the effect of those baby neurotransmitters. what’s it like to be a baby? It’s like being in love in Paris for the time after you’ve had three double-espressos. (Laughter) That’s a way to be, but it does tend to leave you waking up at three o’clock in the morning.
(Laughter)
Now it’s good be a grownup. I don’t want to say too much about how wonderful babies are. It’s good be a grownup. We can do things like tie our and cross the street by ourselves. And it makes that we put a lot of effort into making babies think like do. But if what we want is to be like those butterflies, to have open-mindedness, learning, imagination, creativity, innovation, maybe at least some of the time we should be the adults to start thinking more like children.
(Applause)