What is going on in baby’s mind? If you’d asked people this 30 years ago, most people, psychologists, would have said that this baby was irrational, illogical, — that he couldn’t take the perspective of another or understand cause and effect. In the last 20 years, science has completely overturned that picture. So in some ways, we think this baby’s thinking is like the thinking of the most brilliant scientists.
Let me give you one example of this. One thing that this baby be thinking about, that could be going on in his mind, is trying figure out 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 is to figure out what people are thinking and feeling. And maybe the hardest thing of all is to figure out what other people think and feel isn’t actually exactly like what we think and feel. Anyone who’s politics can testify to how hard that is for some to get. We wanted to know if babies and children could understand this really profound thing about other people. Now the question is: could 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 of consciousness monologue about and birthdays and things like that. So how do actually ask them the question?
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Well it turns out that secret was broccoli. What we did — Betty Rapacholi, who one of my students, and I — was actually to give the babies two bowls of food: bowl of raw broccoli and one bowl of delicious goldfish crackers. Now all of babies, even in Berkley, like the crackers and don’t like the raw broccoli. (Laughter) But what Betty did was to take a little taste of food from each bowl. And would act as if she liked it or she didn’t. So half the time, she acted as 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 of the broccoli and go, “Mmmmm, broccoli. I tasted the broccoli. Mmmmm.” then she would take a little bit of the crackers, and she’d go, “Eww, yuck, crackers. I tasted crackers. Eww, yuck.” So she’d act as if what she was just the opposite of what the babies wanted. We did 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 liked? And the remarkable thing was that 18 month-old babies, just walking and talking, would give her the crackers if she the crackers, but they would give her the broccoli if she liked broccoli. On the other hand, 15 month-olds would stare at her for long time if she acted as if she liked 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 everybody must like. there are two really remarkable things about this. The first 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 that they should actually do things to help other get what they wanted.
Even more remarkably though, the fact that 15 month-olds didn’t this suggests that these 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 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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The you might ask though is: Why do children learn so much? how is it possible for them to learn so in such a short time? I mean, after all, you look at babies superficially, they seem pretty useless. And actually in ways, they’re worse than useless, because we have to put so much time energy into just keeping them alive. But if we turn evolution for an answer to this puzzle of why we spend much time taking care of useless babies, it turns out that there’s actually an answer. we look across many, many different species of animals, just us primates, but also including other mammals, birds, even like kangaroos and wombats, it turns out that there’s a relationship how long a childhood a species has and how big their are compared to their bodies and how smart and flexible they are.
And sort the posterbirds for this idea are the birds up there. On side is a New Caledonian crow. And crows and other corvidae, ravens, rooks so forth, are incredibly smart birds. They’re as smart chimpanzees in some respects. And this is a bird the cover of science who’s learned how to use tool to get food. On the other hand, we have friend the domestic chicken. And chickens and ducks and geese and are basically as dumb as dumps. So they’re very, good at pecking for grain, and they’re not much at doing anything else. Well it turns out that babies, the New Caledonian crow babies, are fledglings. They depend their moms to drop worms in their little open mouths for as long two years, which is a really long time in the life of a bird. Whereas the chickens are mature within a couple of months. So childhood is the why the crows end up on the cover of Science and the chickens end in the soup pot.
There’s something about that long childhood that seems to 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 doing one thing very well. So they seem to be beautifully suited to pecking grain in one environment. creatures, like the crows, aren’t very good at doing anything in particular, but they’re extremely good learning about laws of different environments.
And of course, we beings are way out on the end of the distribution like the crows. have 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 migrated to cover the world and even go outer space. And our babies and children are dependent on us for much than the babies of any other species. My son is 23. (Laughter) And at 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 extremely powerful, great strategy getting on in the world, but it has one disadvantage. And that one big disadvantage is that, until you do all that learning, you’re going 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. Which actually be better?” You want to know all that the mastodons actually show up. And the way the seems to have solved that problem is with a kind of division labor. So the idea is that we have this early when we’re completely protected. We don’t have to do anything. we have to do is learn. And then as adults, we can take 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 thinking about it is that babies and children are like the research and development division of the human species. So they’re the protected sky guys who just have to go out and learn and have good ideas, we’re production and marketing. We have to take all those ideas that learned when we were children and actually put them to use. Another way of about it is instead of thinking of babies and children as being like defective grownups, we should think them as being a different developmental stage of the same — kind of like caterpillars and butterflies — except that they’re actually brilliant butterflies who are flitting around the garden and exploring, and we’re the who are inching along our narrow, grownup, adult path.
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If this true, if these babies are designed to learn — and this evolutionary story would children are for learning, that’s what they’re for — we expect that they would have really powerful learning mechanisms. And in fact, baby’s brain seems to be the most powerful learning 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 ideas of this guy, Reverend Thomas Bayes, who was a statistician and mathematician in the 18th century. And essentially what Bayes did to provide a mathematical way using probability theory to characterize, describe, the way that scientists find about the world. So what scientists do is they have a that they think might be likely to start with. go out and test it against the evidence. The evidence makes them change hypothesis. Then they test that new hypothesis and so on and so forth. what Bayes showed was a mathematical way that you could do that. And that is at the core of the best machine learning programs we have now. And some 10 years ago, I suggested that might be doing the same thing.
So if you want to what’s going on underneath those beautiful brown eyes, I think actually looks something like 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 the world works. All right, now that seem like an even taller order to actually demonstrate. Because all, if you ask even grownups about statistics, they look extremely stupid. How could it that children are doing statistics?
So to test this used a machine that we have called the Blicket Detector. is a box that lights up and plays music when you put some things on and not others. And using this very simple machine, my lab others have done dozens of studies showing just how good babies are at about the world. Let me mention just one that did with Tumar Kushner, my student. If I showed this detector, you would be likely to think to begin that the way to make the detector go would be to put block on top of the detector. But actually, this works in a bit of a strange way. Because you wave a block over the top of the detector, something wouldn’t ever think of to begin with, the detector will activate two out of three times. Whereas, if you the likely thing, put the block on the detector, it only activate two out of six times. So the hypothesis actually has 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 evidence, and we just asked them to make it go. And enough, the four year-olds used the evidence to wave the object on top the detector.
Now there are two things that are really about this. The 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 them 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 unlikely to begin with. And in studies we’ve just been doing in lab, similar studies, we’ve show that four year-olds are better at finding out an unlikely hypothesis than adults are when we them exactly the same task. So in these circumstances, the children are using statistics to out about the world, but after all, scientists also do experiments, we wanted to see if children are doing experiments. When children do experiments call it “getting into everything” or else “playing.”
And there’s been a bunch 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 did was show children that ones made it go and red ones didn’t, and then she them an anomaly. And what you’ll see is that little boy will go through five hypotheses in the space of minutes.
(Video) Boy: How about this? Same as the side.
Alison Gopnik: Okay, so his first hypothesis has just been falsified.
(Laughter)
Boy: This one up, and this one 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 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 his next idea. told the experimenter to do this, to try putting it out onto other location. Not working either.
Boy: Oh, because the light goes only to here, not here. Oh, bottom of this box has electricity in here, but 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 one to make it light up and two on this one to it light up.
AG: Okay,there’s his fifth hypothesis.
Now that a particularly — that is a particularly adorable and little boy, but what Cristine discovered is this is quite typical. If you look at the way children play, you ask them to explain something, what they really do is 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 test five in two minutes? Well, if you go back to those psychologists and philosophers, a of them have said that babies and young children barely conscious if they were conscious at all. And think just the opposite is true. I think babies and children are actually more than we are as adults. Now here’s what we about how adult consciousness works. And adults’ attention and consciousness kind of like a spotlight. So what happens for adults is we that something’s relevant or important, we should pay attention to it. Our consciousness of thing that we’re attending to becomes extremely bright and vivid, and everything else 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 of our brains, sends a signal that makes a part of our brain much more flexible, more plastic, at learning, and shuts down activity in all the rest of our brains. So we have a focused, purpose-driven kind of attention. If we look at babies and young children, we something very different. I think babies and young children seem to have more a lantern of consciousness than a spotlight of consciousness. babies and young children are very bad at narrowing to just one thing. But they’re very good 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 are really good at inducing learning 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 really mean is they’re bad at not paying attention. So they’re bad at getting rid of all interesting things that could tell them something and just looking the thing that’s important. That’s the kind of attention, the of consciousness, that we might expect from those butterflies who are designed learn.
Well if we want to think about a way of getting a taste that kind of baby consciousness as adults, I think the best is think about cases where we’re put in a situation that we’ve never been in before — when we fall love with someone new, or when we’re in a new city for first time. And what happens then is not that our consciousness contracts, it expands, so those three days in Paris seem to be more of consciousness and experience than all the months of a walking, talking, faculty meeting-attending zombie back home. And by way, that coffee, that wonderful coffee you’ve been drinking downstairs, actually mimics effect of those baby neurotransmitters. So what’s it like to a baby? It’s like being in love in Paris for the first time after you’ve three double-espressos. (Laughter) That’s a fantastic way to be, but it does tend to you waking up crying at three 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 do things tie our shoelaces and cross the street by ourselves. And it makes sense that we put a of effort into making babies think like adults do. But if we want is to be like those butterflies, to open-mindedness, open learning, imagination, creativity, innovation, maybe at least some of the time we should getting the adults to start thinking more like children.
(Applause)