What is going 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 perspective another person or understand cause and effect. In the 20 years, developmental science has completely overturned that picture. in some ways, we think that this baby’s thinking like the thinking of the most brilliant scientists.
Let me give you one example of this. One thing that this baby could be about, that could be going on in his mind, is trying to 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 other 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 we think and feel. Anyone who’s followed politics can testify to how hard that is for people to get. We wanted to know if babies and young children 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 a three year-old to tell you what he thinks, what you’ll get is a beautiful stream of consciousness about ponies and birthdays and things like that. So how do we ask them the question?
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Well it turns out the secret was broccoli. What we did — Betty Rapacholi, who was one my students, and I — was actually to give the babies two bowls of food: one bowl raw broccoli and one bowl of delicious goldfish crackers. Now all of babies, even in Berkley, like the crackers and don’t like the broccoli. (Laughter) But then what Betty did was to take a little of food from each bowl. And she would act as if she liked it or didn’t. So half the time, she acted as if liked the crackers and didn’t like the broccoli — just like a and any other sane person. But half the time, she would do is take a little bit of broccoli and go, “Mmmmm, broccoli. I tasted the broccoli. Mmmmm.” And she would take a little bit of the crackers, she’d go, “Eww, yuck, crackers. I tasted the crackers. Eww, yuck.” So she’d as if what she wanted was just the opposite of what the 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 they liked what she liked? And the remarkable thing was that 18 month-old babies, just walking and talking, would give 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 after they stared for a long time, they would just give her crackers, what they thought everybody must like. So there two really remarkable things about this. The first one is that these little 18 month-old have already discovered this really profound fact about human nature, we don’t always want the same thing. And what’s more, they felt that should actually do things to help other people get what they wanted.
Even more though, the fact that 15 month-olds didn’t do this that these 18 month-olds had learned this deep, profound fact about human nature in the three months from they were 15 months old. So children both know and learn more than we ever would have thought. this is just one of hundreds and hundreds of studies over the 20 years that’s actually 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 learn so much in such a short time? I mean, all, if you look at babies superficially, they seem pretty useless. And actually in many ways, they’re than useless, because we have to put so much time energy into just keeping them alive. But if we turn to evolution for answer to this puzzle of why we spend so much time taking care of useless babies, turns out that there’s actually an answer. If we across many, many different species of animals, not just us primates, also including other mammals, birds, even marsupials like kangaroos and wombats, turns out that there’s a relationship between how long a childhood a has and how big their brains are compared to their 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 and so forth, are incredibly birds. They’re as smart as chimpanzees in some respects. And this is a on the cover of science who’s learned how to a tool to get food. On the other hand, we have friend the domestic chicken. And chickens and ducks and and turkeys are basically as dumb as dumps. So they’re very, very good pecking for grain, and they’re not much good at doing else. Well it turns out that the babies, the New Caledonian crow babies, are fledglings. They on their moms to drop worms in their little open mouths for as long as years, which is a really long time in the life of a bird. Whereas the chickens actually mature within a couple of months. So childhood the reason why the crows end up on the cover Science and the chickens end up in the soup pot.
There’s something about that long childhood that to be connected to knowledge and learning. Well what kind of explanation could we for this? Well some animals, like the chicken, seem to be beautifully to doing just one thing very well. So they to be beautifully suited to pecking grain in one environment. Other creatures, the crows, aren’t very good at doing anything in particular, but they’re extremely good at learning about laws of environments.
And of course, we human beings are way out the end of the distribution like the crows. We have bigger brains relative to bodies by far than any other animal. We’re smarter, we’re more flexible, can learn more, we survive in more different environments, we to cover the world and even go to outer space. And babies and children are dependent on us for much longer than babies of any other species. My son is 23. (Laughter) And at least they’re 23, we’re still popping those worms into those little mouths.
All right, why would we see this correlation? Well an idea is that strategy, that learning strategy, is an extremely powerful, great strategy for getting on the world, but it has one big disadvantage. And one big disadvantage is that, until you actually do that learning, you’re going to be helpless. So you don’t want to have the mastodon charging at you be saying to yourself, “A slingshot or maybe a spear might work. Which would be better?” You want to know all that before the mastodons actually show up. And the way the seems to have solved that problem is with a kind of of labor. So the idea is that we have this period when we’re completely protected. We don’t have to anything. All we have to do is learn. And then as adults, we can all those things that we learned when we were babies and children and put them to work to do things 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 protected blue sky guys who just have to go out and learn 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 about is instead of thinking of babies and children as being like defective grownups, we think about them as being a different developmental stage of same species — kind of like caterpillars and butterflies — that they’re actually the 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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this is true, if these babies are designed to — and this evolutionary story would say children are learning, that’s what they’re for — we might expect they would have 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 to be a lot better. And there’s a revolution in our understanding of machine learning recently. it all depends on the ideas of this guy, Reverend Thomas Bayes, who was a statistician and mathematician the 18th century. And essentially what Bayes did was to a mathematical way using probability theory to characterize, describe, the way that scientists find out the world. So what scientists do is they have a hypothesis that think might be likely to start with. They go out 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 mathematics is at the core of the best machine learning that we have now. And some 10 years ago, I suggested babies might be doing the same thing.
So if want to know what’s going on underneath those beautiful 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 conditional probabilities that they’re to figure out how the world works. All right, now that might seem like an even taller order actually demonstrate. Because after all, if you ask even about statistics, they look extremely stupid. How could it that children are doing statistics?
So to test this we used machine that we have called the Blicket Detector. This is a box that lights up plays music when you put some things on it not others. And using this very simple machine, my lab and others have done dozens of studies just how good babies are at learning about the world. me mention just one that we did with Tumar Kushner, my student. If I showed you this detector, you be likely to think to begin with that the way make the detector go would be to put a block on of the detector. But actually, this detector works in bit of a strange way. Because if you wave a block over the top the detector, something you wouldn’t ever think of to begin with, the detector actually activate two out of three times. Whereas, if you do likely thing, put the block on the detector, it only activate two out of six times. So the unlikely hypothesis actually stronger evidence. It looks as if the waving is a more strategy than 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 sure enough, the four year-olds the evidence to wave the object on top of the detector.
Now there are two that are really interesting about this. The first one is, again, remember, these are four year-olds. They’re learning how to count. But unconsciously, they’re doing these quite calculations that will give them a conditional probability measure. And other interesting thing is that they’re using that evidence to get to idea, get to a hypothesis about the world, that seems very unlikely to begin with. And in we’ve just been doing in my lab, similar studies, we’ve that four year-olds are actually better at finding out an hypothesis than adults are when we give them exactly same task. So in these circumstances, the children are using statistics to find out about world, but after all, scientists also do experiments, and we wanted to see if children are 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 use Blicket Detectors. And what she did was show children yellow ones made it go and red ones didn’t, then she showed them an anomaly. And what you’ll is that this little boy will go through five hypotheses in the space two minutes.
(Video) Boy: How about this? Same as other side.
Alison Gopnik: Okay, so his first hypothesis just been falsified.
(Laughter)
Boy: This one lighted up, and one nothing.
AG: Okay, he’s got his experimental notebook out.
Boy: What’s making light up. (Laughter) I don’t know.
AG: Every scientist will that expression of despair.
(Laughter)
Boy: Oh, it’s because this to be like this, and this needs to be this.
AG: Okay, hypothesis two.
Boy: That’s why. Oh.
(Laughter)
AG: Now this is his next idea. He told the to 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 has electricity here, but this doesn’t have electricity.
AG: Okay, that’s a hypothesis.
Boy: It’s lighting up. So when you put four. So put four on this one to make it light up and two on this one to make light up.
AG: Okay,there’s his fifth hypothesis.
Now that a particularly — that is a particularly adorable and articulate boy, but what Cristine discovered is this is actually quite typical. If you look the way children play, when you ask them to explain something, they really do is do a series of experiments. This is actually pretty typical of year-olds.
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Well, what’s it like to be this kind of creature? What’s like to be one of these brilliant butterflies who can five hypotheses in two minutes? Well, if you go to those psychologists and philosophers, a lot of them have said babies and young children were barely conscious if they were conscious at all. 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’ and consciousness look kind of like a spotlight. So what for adults is we decide that something’s relevant or important, should pay attention to it. Our consciousness of that thing that we’re attending to becomes extremely and vivid, and everything else sort of goes dark. And we even know something about the way brain does this.
So what happens when we pay attention is that the prefrontal cortex, the sort executive part of our brains, sends a signal that a little part of our brain much more flexible, plastic, better at learning, and shuts down activity in all the rest of our brains. So we a very focused, purpose-driven kind of attention. If we look at and young children, we see something very different. I think babies and young children seem to have more a lantern of consciousness than a spotlight of consciousness. So babies and children are very bad at narrowing down to just thing. But they’re very good at taking in lots of from lots of different sources at once. And if you actually look in their brains, 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 we say that babies and young children bad at paying attention, what we really mean is that they’re bad at paying attention. So they’re bad at getting rid of all the interesting things that could tell something and just looking at the thing that’s important. That’s kind of attention, the kind of consciousness, that we expect from those 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 thing is think about cases where we’re put in a new that we’ve never been in before — when we fall in love with someone new, or when we’re a new city for the first time. And what then is not that our consciousness contracts, it expands, so that those 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 wonderful you’ve been 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 for the first time after you’ve had three double-espressos. (Laughter) That’s a fantastic way to be, but does tend to leave you waking up crying at o’clock in the morning.
(Laughter)
Now it’s good to be a grownup. don’t want to say too much about how wonderful babies are. It’s good to be a grownup. can do things like tie our shoelaces and cross the street by ourselves. And it sense that we put a lot of effort into making think like adults do. But if what we want to be like those butterflies, to have open-mindedness, open learning, imagination, creativity, innovation, maybe at least some of the time we be getting the adults to start thinking more like children.
(Applause)