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 — he couldn’t take the perspective of another person or understand cause and effect. the last 20 years, developmental science has completely overturned that picture. So some ways, we think that this baby’s thinking is like the of the most brilliant scientists.
Let me give you just one example of this. One thing this baby could be thinking about, that could be going on in his mind, is to 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 is to figure out what other people are thinking and feeling. And maybe the hardest thing of is to figure out that what other people think feel isn’t actually exactly like what we think and feel. Anyone who’s followed politics can testify how hard that is for some people to get. We wanted know if babies and young children could understand this really profound thing about people. Now 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 a stream of consciousness monologue about ponies and birthdays and things like that. how do we actually ask them the question?
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Well it turns out the secret was broccoli. What we did — Betty Rapacholi, who one of my students, and I — was actually to 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 broccoli. (Laughter) But then what Betty did was to take a little taste food from each bowl. And she would act as if she liked it or she didn’t. So half time, she acted as if she liked the crackers and didn’t like the broccoli — just like baby and any other sane person. But half the time, what she would do is take a little of the broccoli and go, “Mmmmm, broccoli. I tasted the broccoli. Mmmmm.” And then she would take little bit of the crackers, and she’d go, “Eww, yuck, crackers. I 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 you give me some?”
So the question is: would the baby give her, what they liked or what she liked? And the remarkable was that 18 month-old babies, just barely walking and talking, would give her the crackers if liked the crackers, but they would give her the if she liked the broccoli. On the other hand, 15 month-olds would stare at her a 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 the crackers, what they thought everybody must like. So are two really remarkable things about this. The first is that these little 18 month-old babies have already discovered this profound fact about human nature, that we don’t always the same thing. And what’s more, they felt that should actually do things to help other people get they wanted.
Even more remarkably though, the fact that 15 month-olds didn’t do this suggests that 18 month-olds had learned this deep, profound fact about human in the three months from when they were 15 months old. So children know more and learn more than we ever would have thought. And this is one of hundreds and hundreds of studies over the last 20 years that’s actually it.
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The question you might ask though is: do children learn so much? And how is it for them to learn so much in such a 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 we to put so much time and energy into just keeping them alive. But we turn to evolution for an answer to this 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 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 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. one side is a New Caledonian crow. And crows other corvidae, ravens, rooks and so forth, are incredibly birds. They’re as smart as chimpanzees in some respects. And this is a bird the cover of science who’s learned how to use a to get food. On the other hand, we have our friend the domestic chicken. And and ducks and geese and turkeys are basically as dumb as dumps. So they’re very, good at pecking for grain, and they’re not much good at doing anything else. Well it out that the babies, the New Caledonian crow babies, are fledglings. They depend their moms to drop worms in their little open mouths for long as two years, which is a really long time in the life of a bird. Whereas chickens are actually mature within a couple of months. So childhood the 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 childhood that seems to be to knowledge and learning. Well what kind of explanation could have for this? Well some animals, like the chicken, seem be beautifully suited to doing just one thing very well. So they seem be beautifully suited to pecking grain in one environment. creatures, like the crows, aren’t very good at doing in 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 like the crows. We have bigger brains relative to our by far than any other animal. We’re smarter, we’re more flexible, we can more, we survive in more different environments, we migrated cover the world and even go to outer space. And babies and children are dependent on us for much longer than the babies of any other species. My is 23. (Laughter) And at least until they’re 23, we’re still popping worms into those little open mouths.
All right, why would we see this correlation? Well an idea is that strategy, that learning strategy, is an extremely powerful, great strategy getting on in the world, but it has one big disadvantage. that one big disadvantage is that, until you actually do all that learning, you’re going to helpless. So you don’t want to have the mastodon at you and be saying to yourself, “A slingshot maybe a spear might work. Which would actually be better?” want to know all that before the mastodons actually 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 adults, we can take all those things that we learned when we were babies and children and actually 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 of the human species. So they’re the protected sky guys who just have to go out and learn and good ideas, and we’re production and marketing. We have to all those ideas that we learned when we were children and actually put them to use. Another of thinking about it is instead of thinking of babies children as being like defective grownups, we should think about them as being a different developmental of the same species — kind of like caterpillars and butterflies — except they’re actually the brilliant butterflies who are flitting around the garden and exploring, and we’re the caterpillars are inching along our narrow, grownup, adult path.
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this is true, if these babies are designed to learn — and 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 to be the most powerful learning computer on the planet. But computers are actually getting to be a lot better. And there’s been a in our understanding of machine learning recently. And it all on the ideas of this guy, the Reverend Thomas Bayes, was a statistician and mathematician in the 18th century. And essentially what Bayes did was 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. 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 is at 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 going underneath those beautiful brown eyes, I think it actually looks something 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 out how world works. All right, now that might seem like even taller order to actually 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 we have called the Blicket Detector. This is a box that lights up and plays when you put some things on it and not others. using this very simple machine, my lab and others have done of studies showing just how good babies are at about the world. Let me mention just one that we did with Tumar Kushner, my student. If I you this detector, you would be likely to think to with that the way to make the detector go would be to a block on top of the detector. But actually, this detector works in a of a strange way. Because if you wave a block over the of the detector, something you wouldn’t ever think of to begin with, the detector will actually two out of three times. Whereas, if you do the likely thing, put the block on the detector, will only activate 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 other strategy. So we did just this; gave four year-olds this pattern of evidence, and we just asked to make it go. And sure enough, the four year-olds the evidence to wave the object on top of 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 to count. But unconsciously, they’re doing these quite complicated calculations will give them a conditional probability measure. And the interesting thing is that they’re using that evidence to to an idea, get to a hypothesis about the world, that seems unlikely to begin with. And in studies we’ve just been in my lab, similar studies, we’ve show that four year-olds actually better at finding out an unlikely hypothesis than are when we give them exactly the same task. So these circumstances, the children are using statistics to find out about the world, but after all, scientists also experiments, and we wanted to see if children are experiments. When children do experiments we call it “getting everything” or else “playing.”
And there’s been a bunch of studies recently that have shown this playing around is 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 ones made it and red ones didn’t, and then she showed 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 other side.
Alison Gopnik: Okay, so his hypothesis 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 will that expression of despair.
(Laughter)
Boy: Oh, it’s because this needs be like this, and this needs to be like this.
AG: Okay, two.
Boy: That’s why. Oh.
(Laughter)
AG: Now this is his idea. He told the experimenter to do this, to try putting out onto the other location. Not working either.
Boy: Oh, because light goes only to here, not here. Oh, the bottom of this box has electricity here, but this doesn’t have 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 up and two on this one to make it light up.
AG: Okay,there’s his fifth hypothesis.
Now is a particularly — that is a particularly adorable and articulate little boy, what Cristine discovered is this is actually quite typical. If you look at the way play, when you ask them to explain something, what they really 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 it like to one of these brilliant butterflies who can test five hypotheses two minutes? Well, if you go back to those and philosophers, a lot of them have said that babies and young children were barely if they were conscious at all. And I think the opposite is true. I think babies and children actually more conscious than we are as adults. Now here’s what we know about how consciousness works. And adults’ attention and consciousness look kind of like a spotlight. So happens for adults is we decide that something’s relevant or important, we should attention to it. Our consciousness of that thing that we’re to becomes extremely bright and vivid, and everything else sort of goes dark. And we even know about the way the brain does this.
So what happens when we pay attention is the prefrontal cortex, the sort of executive part 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. we have a very focused, purpose-driven kind of attention. If we at babies and young children, we see something very different. I think babies and young children seem to have of a lantern of consciousness than a spotlight of consciousness. So babies and young children very bad at narrowing down to just one thing. But they’re very good 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 really good at inducing and plasticity, and the inhibitory parts haven’t come on yet. when we say that babies and young children are bad paying attention, what we really mean is that they’re bad at not attention. So they’re bad at getting rid of all interesting things that could tell them something and just at the thing that’s important. That’s the kind of attention, the of consciousness, that we might expect from those butterflies who are to learn.
Well if we want to think about a way of a taste of that 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 been in before — when we fall in love someone new, or when we’re in a new city for the first time. 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 the way, 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 after you’ve had three double-espressos. (Laughter) That’s a fantastic to be, but it does tend to leave you waking up at three o’clock in the morning.
(Laughter)
Now it’s good to a grownup. I don’t want to say too much about wonderful babies are. It’s good to be a grownup. We can do like tie our shoelaces and cross the street by ourselves. And it makes sense that we put lot of effort into making babies think like adults do. But what 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 thinking more like children.
(Applause)