What going on in this baby’s mind? If you’d asked people 30 years ago, most people, including psychologists, would have said that this baby was irrational, illogical, — that he couldn’t take the perspective of another person or understand and effect. In the last 20 years, developmental science has completely overturned that picture. in some ways, we think that this baby’s thinking is like the thinking of the brilliant scientists.
Let me give you just one example of this. One thing that baby could be thinking about, that could be going in his mind, is trying to figure out what’s on in the mind of that other baby. After all, one of things that’s hardest for all of us to do to figure out what other people are thinking and feeling. maybe the hardest thing of all is to figure that what other people think and feel isn’t actually like what we think and feel. Anyone who’s followed politics can testify to how hard that for some people to get. We wanted to know if babies and young could understand this really profound thing about other people. the question is: How could we ask them? Babies, all, can’t talk, and if you ask a three year-old tell you what he thinks, what you’ll get is beautiful stream of consciousness monologue about ponies and birthdays and like that. So how do we actually ask them the question?
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Well it out that the secret was broccoli. What we did — Rapacholi, who 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 to take little taste of food from each bowl. And she act as if she liked it or she didn’t. half the time, she acted as if she liked the crackers and didn’t the broccoli — just like a baby and any other sane person. But half the time, what she do is take a little bit of the broccoli 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 was just the opposite of what the babies wanted. We 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 the baby give her, what they 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, they would give her the broccoli if she liked broccoli. On the other hand, 15 month-olds would stare at her for a long time if she as 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, they thought everybody must like. So there are two really remarkable things about this. The first one that these little 18 month-old babies have already discovered this really profound fact about human nature, that don’t always 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, the that 15 month-olds didn’t do this 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 learn than we ever would have thought. And this is one of hundreds and hundreds of studies over the last 20 that’s actually demonstrated it.
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The question you might ask though is: Why do learn so much? And how is it possible for to learn so much in such a short time? mean, after all, if you look at babies superficially, they seem pretty useless. And in many 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 so much time taking care of useless babies, it turns that there’s actually an answer. If we look across many, different species of animals, not just us primates, but also other mammals, birds, even marsupials like kangaroos and wombats, it out that there’s a relationship between how long a childhood a species has and how big brains are compared to their bodies and how smart and they are.
And sort of the posterbirds for this idea are the birds up there. On one is a New Caledonian crow. And crows and other corvidae, ravens, rooks so forth, are incredibly smart birds. They’re as smart as chimpanzees in some respects. And this is a on the cover of science who’s learned how to use a tool to get food. On other hand, we have our friend the domestic chicken. And chickens and ducks geese and turkeys are basically as dumb as dumps. they’re very, very good at pecking for grain, and they’re not good 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 as long as two years, which is a really long time in the of a bird. Whereas the chickens are actually mature within couple of months. So childhood is the reason why the crows end up the cover of Science and the chickens end up in the pot.
There’s something about that long childhood that seems to be connected to knowledge and learning. Well kind of explanation could we have for this? Well some animals, the chicken, seem to be beautifully 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 in particular, but they’re extremely good at learning about of different environments.
And of course, we human beings are way out on the end of distribution like the crows. We have bigger brains relative to our bodies by far any other animal. We’re smarter, we’re more flexible, we can more, we survive in more different environments, we migrated to cover world and even go to outer space. And our babies and are dependent on us for much longer than the babies of any other species. My son 23. (Laughter) And 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 an idea is 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 big is that, until you actually do all that learning, you’re to be helpless. So you don’t want to have mastodon 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 the mastodons show up. And the way the evolutions seems to have solved that problem with a kind of division of labor. So the idea is we have this early period when we’re completely protected. We don’t to do anything. All we have to do is learn. And then as adults, can take all those things that we learned when were babies and children and actually put them to to do things out there in the world.
So 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 blue sky guys who just have to go out learn and have good ideas, and we’re production and marketing. We have take all those ideas that we learned when we were children actually put them to use. Another way of thinking 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 of like caterpillars butterflies — except that they’re actually the brilliant butterflies who are flitting 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 learn — and this evolutionary story would say children are learning, that’s what they’re for — we might expect that they have really powerful learning mechanisms. And in fact, the baby’s brain to be the most powerful learning computer on the planet. But real computers are actually getting to a lot better. And there’s been a revolution in understanding of machine learning recently. And it all depends the ideas of this guy, the Reverend Thomas Bayes, who was a and mathematician in the 18th century. And essentially what Bayes did was to provide mathematical way using probability theory to characterize, describe, the way scientists find out about the world. So what scientists is they have a hypothesis that they think might likely to start with. They go out and test it against the evidence. The evidence makes change that hypothesis. Then they test that new hypothesis so on and so forth. And what Bayes showed was a mathematical way you could do that. And that mathematics is at core of the best machine learning programs that we have now. And some 10 ago, I suggested that babies might be doing the thing.
So if you want to know what’s going on those beautiful brown eyes, I think it actually looks something this. This is Reverend Bayes’s notebook. So I think those babies actually making complicated calculations with conditional probabilities that they’re revising to figure out how the works. All right, now that might seem like an taller order to actually demonstrate. Because after all, if you ask grownups about statistics, they look extremely stupid. How could it be that are doing statistics?
So to test this we used a that we have called the Blicket Detector. This is a box that lights up and plays music you put some things on it and not others. And using this simple machine, my lab and others have done dozens of studies showing how 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 with that the way to make the detector go would be to put a block top of the detector. But actually, this detector works in 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 of three times. Whereas, you do the likely thing, put the block on detector, it will only activate two out of six times. So the unlikely hypothesis actually has evidence. It looks as if the waving is a more effective strategy than the strategy. So we did just this; we gave four year-olds this of evidence, and we just asked them to make it go. sure enough, the four year-olds used the evidence to wave the on top of the detector.
Now there are two things that really interesting about this. The first one is, again, remember, these are four year-olds. They’re just learning to count. But unconsciously, they’re doing these quite complicated calculations that give them a conditional probability measure. And the other interesting thing that they’re using that evidence to get to an idea, get a hypothesis about the world, that seems very unlikely to begin with. And in studies we’ve just been in my lab, similar studies, we’ve show that four year-olds are actually better at out an unlikely hypothesis than adults are when we give them exactly the same task. So in circumstances, the children are using statistics to find out about world, but after all, scientists also do experiments, and we wanted to see if 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 that have shown this playing is really a kind of experimental research program. Here’s one from Cristine Legare’s lab. What Cristine was use our Blicket Detectors. And what she did was show children that yellow 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 hypotheses in the space of two minutes.
(Video) Boy: about this? Same as the other side.
Alison Gopnik: Okay, so his hypothesis has just been falsified.
(Laughter)
Boy: This one lighted up, and 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 will recognize expression of despair.
(Laughter)
Boy: Oh, it’s because 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, try putting it out onto the other location. Not working either.
Boy: Oh, because the light only to here, not here. Oh, the bottom of this box has electricity in here, but this doesn’t electricity.
AG: Okay, that’s a fourth hypothesis.
Boy: It’s lighting up. when you put four. So you put four on this one to make it up and two on this one to make it light up.
AG: Okay,there’s fifth hypothesis.
Now that is a particularly — that is a adorable and articulate 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 do series of experiments. This is actually pretty typical of 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 can test five hypotheses in two minutes? Well, if go back to those psychologists and philosophers, a lot of them said that babies and young children were barely conscious they were conscious at all. And 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 look kind of like a spotlight. So what happens adults is we decide that something’s relevant or important, we should attention to it. Our consciousness of that thing that we’re attending to becomes extremely bright and vivid, and else sort of goes dark. And we even know about the way the brain does this.
So what happens when we pay attention is that the cortex, the sort of executive part of our brains, sends a signal makes a little part of our brain much more flexible, more plastic, better at learning, shuts down activity in all the rest of our brains. So we have a very focused, purpose-driven of attention. If we look at babies and young children, we see something very different. I think babies young children seem to have more of a lantern consciousness than a spotlight of consciousness. So babies and young children are very bad at down to just one thing. But they’re very good at taking in lots of information from of different sources at once. And if you actually in their 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. when we say that babies and young children are bad at paying attention, what we mean is that they’re bad at not paying attention. So they’re at getting rid 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 might expect from butterflies who are designed to learn.
Well if we want 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 in love with someone new, or when we’re in a city for the first time. And what happens then not that our consciousness contracts, it expands, so that three days in Paris seem to be more full of consciousness and experience all the months of being a walking, talking, faculty meeting-attending back home. And by the way, that coffee, that coffee you’ve been drinking downstairs, actually mimics the effect of those baby neurotransmitters. So what’s it to be a baby? It’s like being in love in Paris for first time after you’ve had three double-espressos. (Laughter) That’s fantastic way to be, but it does tend to leave you up crying at three o’clock in the morning.
(Laughter)
Now it’s good be a grownup. I don’t want to say too about how wonderful babies are. It’s good to be a grownup. We can do things like tie shoelaces and cross the street by ourselves. And it makes sense that we put a lot of into making babies think like adults do. But if what we is to be like those butterflies, to have open-mindedness, open learning, imagination, creativity, innovation, at least some of the time we should be getting adults to start thinking more like children.
(Applause)