What going on in this baby’s mind? If you’d asked this 30 years ago, most people, including psychologists, would said that this baby was irrational, illogical, egocentric — that he couldn’t take the perspective of another person understand cause and effect. In the last 20 years, developmental science has overturned that picture. So in some ways, we think this baby’s thinking is like the thinking of the most scientists.
Let me give you just one example of this. One that this baby could be thinking about, that could be on in his mind, is trying to figure out what’s going on in the mind of that other baby. all, one of the things that’s hardest for all us to do is to figure out what other are thinking and feeling. And maybe the hardest thing of all to figure out that what other people think and feel isn’t actually exactly like what we and feel. Anyone who’s followed politics can testify to hard that is for some people to get. We to know if babies and young children could understand this really profound about other people. Now the question is: How could we them? Babies, after all, can’t talk, and if you ask a three year-old to tell you he thinks, what you’ll get is a beautiful stream of consciousness monologue about ponies and birthdays things like that. So how do we actually ask the question?
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Well it turns out that the was broccoli. What we did — Betty Rapacholi, who was of my students, and I — was actually to give the babies bowls of food: one bowl of raw broccoli and one bowl of delicious goldfish crackers. Now of the babies, even in Berkley, like the crackers don’t like the raw broccoli. (Laughter) But then what Betty did to take a 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 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.” And then she take a 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. We did this with 15 18 month-old babies. And then she would simply put her out and say, “Can you give me some?”
So question is: What would the baby give her, what liked or what she liked? And the remarkable thing was that 18 month-old babies, barely walking and talking, would give her the crackers if liked the crackers, but they would give her the broccoli if she the 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 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 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 that they should actually do things to other people 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, fact about human nature in the three months from when were 15 months old. So children both know more learn more than we ever would have thought. And this is just one of hundreds and of studies over the 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 it possible for them to learn so much in such a short time? mean, after all, if you look at babies superficially, seem pretty useless. And actually in many ways, they’re worse useless, because we have to put so much time and energy just keeping them alive. But if we turn to evolution for an answer 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 just us primates, but also including 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 their are compared to their bodies and how smart and flexible are.
And sort of 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 use a tool get food. On the other hand, we have our the domestic chicken. And chickens and ducks and geese turkeys 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 the babies, the New Caledonian crow babies, fledglings. They depend on their moms to drop worms in their open mouths for as long as two years, which is a really long time in the of a bird. Whereas the chickens are actually mature within a couple months. So childhood is the reason why the crows end up the cover of Science and the chickens end up in the soup pot.
There’s something about long childhood that seems to be connected to knowledge and learning. what kind of explanation could we have for this? Well some animals, like the chicken, to be beautifully suited to doing just one thing very well. they seem to be beautifully suited to pecking grain one environment. Other creatures, like the crows, aren’t very at doing anything in particular, but they’re extremely good at learning about laws different environments.
And of course, we human beings are way out the end of the 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 learn more, we survive in more different environments, we migrated cover the world and even go to outer space. And our babies and children are dependent on for much longer than the 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 open mouths.
All right, why would we see correlation? Well an idea is that that strategy, that learning strategy, is an powerful, great strategy for getting on in the world, but it has big disadvantage. And that one big disadvantage is that, 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 or maybe a might work. Which would actually be better?” You want know all that before the mastodons actually show up. And the way the evolutions seems have solved that problem is with a kind of division of labor. So the idea is we have this early period when we’re completely protected. We don’t have to do anything. All we to do is learn. And then as adults, we can take those things that we learned when we were babies and and actually put them to work to do things there in the world.
So one way of thinking about it that babies and young children are like the research and development division of the human species. So they’re protected blue sky guys who just have to go out learn and have good ideas, and we’re production and marketing. We have to all those ideas that we learned when we were children and actually them to use. Another way of thinking about 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 caterpillars and butterflies — except that they’re actually the butterflies who are flitting around the garden and exploring, we’re the caterpillars 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 that they would have really powerful learning mechanisms. And fact, the 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 our understanding of machine learning recently. And it all depends the ideas of this guy, the 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 scientists find out about the world. So what scientists do is they have a hypothesis that they might be likely to start with. They go out and test it the evidence. The evidence makes them change that hypothesis. Then they that new hypothesis and so on and so forth. And Bayes showed was a mathematical way that you could do that. And that mathematics is at core of the best machine learning programs that we now. And some 10 years ago, I suggested that babies might be doing same thing.
So if you want to know what’s going underneath those beautiful brown eyes, I think it actually something like this. This is Reverend Bayes’s notebook. So I think those babies are actually making complicated calculations conditional probabilities that they’re revising to figure out how the world works. All right, now that might like an even taller order to actually demonstrate. Because after all, if you ask even grownups statistics, they look extremely stupid. How could it be children are doing statistics?
So to test this we a machine that we have called the Blicket Detector. is a box that lights up and plays music 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 learning about the world. Let mention just one that we did with Tumar Kushner, my student. I showed you this detector, you would be likely to think to begin with the way to make the detector go would be to put a on top of the detector. But actually, this detector 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 actually activate two out of three times. Whereas, if do the likely thing, put the block on the detector, it will only activate out of six times. So the unlikely hypothesis actually has evidence. It looks as if the waving is a more effective strategy than other strategy. So we did just this; we gave four year-olds this of evidence, and we just asked them to make it go. And sure enough, the year-olds used 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 that will give them a probability measure. And the other interesting thing is that they’re using that evidence get to an idea, get to a hypothesis about the world, 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 finding out an unlikely hypothesis than adults are when we give them exactly the same task. So 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 are doing experiments. When children do experiments we call “getting into everything” or else “playing.”
And there’s been bunch of interesting studies recently that have shown this playing around is really a kind of experimental 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 an anomaly. And what you’ll see is that this little boy go through five hypotheses in the space of two minutes.
(Video) Boy: about this? Same as the other side.
Alison Gopnik: Okay, so his first hypothesis 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 will recognize that expression of despair.
(Laughter)
Boy: Oh, it’s because this needs to be like this, this needs to be like this.
AG: Okay, hypothesis two.
Boy: That’s why. Oh.
(Laughter)
AG: Now this is his idea. He told the experimenter to do this, to try it out onto the other location. Not working either.
Boy: Oh, because light goes only to here, not here. Oh, the bottom this box has electricity in here, but this doesn’t have electricity.
AG: Okay, that’s fourth hypothesis.
Boy: It’s lighting up. So when you put four. you put four on this one to make it light 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 articulate little boy, but what Cristine discovered is this actually quite typical. If you look at the way play, when you ask them to explain something, what really do is do a series of experiments. This actually pretty typical of four year-olds.
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Well, what’s like to be this kind of creature? What’s it to be one of these brilliant butterflies who can five hypotheses in two minutes? Well, if you go back to those and philosophers, a lot of them have said that babies and young children were conscious if they were conscious at all. And I think just the opposite true. I think babies and children are actually more than we are as adults. Now here’s what we know about how adult consciousness works. And adults’ and consciousness look kind of like a spotlight. So happens for adults is we decide that something’s relevant important, we should pay attention to it. Our consciousness that thing that we’re attending to becomes extremely bright and vivid, and everything sort of goes dark. And we even know something about the way the brain does this.
So what when we pay attention is that the prefrontal cortex, the sort of executive part of brains, sends a signal that makes a little part of brain much more flexible, more plastic, better at learning, and shuts down activity in all the rest our brains. So we have a very focused, purpose-driven kind of attention. If look at babies and young children, we see something different. I think babies and young children seem to have of 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 of information from lots of different sources at once. if you actually look in their brains, you see that they’re flooded with neurotransmitters that are really good at inducing learning and plasticity, the inhibitory parts haven’t come on yet. So when say that babies and young children are bad at paying attention, what we mean is that they’re bad at not paying attention. they’re bad at getting rid of all the interesting that could tell them something and just looking at the thing that’s important. That’s kind of attention, the kind of consciousness, that we might expect from those butterflies are designed 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 thing is think about cases where we’re put in a new situation that we’ve been in before — when we fall in love with someone new, or when we’re in a city for the first time. And what happens then is not that our contracts, it expands, so that those three days in Paris seem to be more full consciousness and experience than all the months of being a walking, talking, meeting-attending zombie back home. And 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 love in Paris for the first 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 about how wonderful babies are. It’s good to be grownup. We can do things like tie our shoelaces and cross street by ourselves. And it makes sense that we put a lot of effort making babies think like adults do. But if what we want is to be like those butterflies, to open-mindedness, open learning, imagination, creativity, innovation, maybe at least some of time we should be getting the adults to start more like children.
(Applause)