What is going on this baby’s mind? If you’d asked people this 30 years ago, most people, including psychologists, would have said this baby was irrational, illogical, egocentric — that he couldn’t take perspective of 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 is 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 baby. After all, one of the things that’s hardest for of us to do is to figure out what other are thinking and feeling. And maybe the hardest thing of all is to figure out that other people think and feel isn’t actually exactly like what think and feel. Anyone who’s followed politics can testify to how that is for some people to get. We wanted know if babies and young children could understand this really profound thing other 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 beautiful of consciousness monologue about ponies and birthdays and things like that. So do we actually ask them the question?
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Well it turns out that secret was broccoli. What we did — Betty Rapacholi, who was one my students, and I — was actually to give the babies bowls of food: one bowl of raw broccoli and one of delicious goldfish crackers. Now all of the babies, even in Berkley, like crackers and don’t like the raw broccoli. (Laughter) But then what Betty did was take a little taste of food from each bowl. And she would act if she liked it or she didn’t. So half the time, she as if she liked the crackers and didn’t like the broccoli — just a baby and any other sane person. But half the time, what she would do take a little bit of the broccoli and go, “Mmmmm, broccoli. I the broccoli. Mmmmm.” And then she would take a bit of the crackers, and she’d go, “Eww, yuck, crackers. tasted the crackers. Eww, yuck.” So she’d act as if what she wanted just the opposite of what the babies wanted. We did this with 15 18 month-old babies. And then she would simply put her hand and say, “Can you give me some?”
So the question is: What the baby give her, what they liked or what she liked? the remarkable thing was that 18 month-old babies, just barely 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 her for a time if she acted as if she liked the broccoli, like they couldn’t figure out. But then after they stared for a long time, they would just give her crackers, what they thought everybody must like. So there are two really remarkable things about this. first one is that these little 18 month-old babies already discovered 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 15 month-olds didn’t do this suggests that these 18 month-olds had this deep, profound fact about human nature in the months from when they were 15 months old. So children know more and learn more than we ever would have thought. this is just one of hundreds and hundreds of studies over the last 20 years that’s demonstrated it.
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The question you might ask though is: Why do children learn so much? how is it possible for them to learn so much in a short time? I mean, after all, if you look at superficially, they seem pretty useless. And actually in many ways, they’re worse useless, because we have to put so much time and energy into just keeping them alive. But if turn to evolution for an answer to this puzzle of why we so 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, not just us primates, but also other mammals, birds, even marsupials like kangaroos and wombats, it turns out 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 they are.
And of the posterbirds for this idea are the birds there. On one side is a New Caledonian crow. crows and other corvidae, ravens, rooks and so forth, incredibly smart birds. They’re as smart as chimpanzees in respects. And this is a bird on the cover of science who’s learned how use a tool to get food. On the other hand, have our friend the domestic chicken. And chickens and ducks geese and turkeys are basically as dumb as dumps. So they’re very, very good pecking for grain, and they’re not much good at anything else. Well it turns out that the babies, the New Caledonian crow babies, are fledglings. depend on their moms to drop worms in their little open mouths as long as two years, which is a really time in the life of a bird. Whereas the chickens are actually mature a couple of months. So childhood is the reason why the end up on the cover of Science and the chickens end up in the soup pot.
There’s something that 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, seem to be suited to doing just one thing very well. So they seem to 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 on 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, we can more, we survive in more different environments, we migrated to cover world and even go to outer space. And our babies and children are dependent us for much longer than the babies of any other species. My son is 23. (Laughter) And least until they’re 23, we’re still popping those worms into little open mouths.
All right, why would we see correlation? Well an idea is that that strategy, that learning strategy, is extremely powerful, great strategy for getting on in the world, it has one big disadvantage. And that one big disadvantage is that, until you actually do all learning, you’re going to be helpless. So you don’t to have the mastodon charging at you and be to yourself, “A slingshot or maybe a spear might work. Which actually be better?” You want to know all that before the mastodons actually show up. the way the evolutions seems to have solved that problem with a kind of division of labor. So the idea is that we have this 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 all those things that we learned we were babies and children and actually put them to work to do things there in the world.
So one way of thinking about it is that and young children are like the research and development division the human species. So they’re the protected 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 and actually put them to use. Another way of about it is instead of thinking of babies and children as being like grownups, we should think about them as being a different stage of the same species — kind of like and butterflies — except that they’re actually the brilliant butterflies are flitting around the garden and exploring, and we’re caterpillars who are inching along our narrow, grownup, adult path.
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If this true, if these babies are designed to learn — this 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 seems to the most powerful learning computer 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 on the ideas of this guy, the Thomas Bayes, who was a statistician and mathematician in 18th century. And essentially what Bayes did was to provide a mathematical using probability theory to characterize, describe, the way that scientists find out the world. So what scientists do is they have a hypothesis they think might be likely to start with. They go out and test it the evidence. The evidence makes them change that hypothesis. Then test that new hypothesis and so on and so forth. And what showed was a mathematical way that you could do that. And that mathematics at the core of the best machine learning programs we have now. And some 10 years ago, I suggested that babies be doing the same thing.
So if you want know what’s going on underneath those beautiful brown eyes, I think it actually looks like 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 even order to actually demonstrate. Because after all, if you even grownups about statistics, they look extremely stupid. How could it be that children are statistics?
So to test this we used a machine that we called the Blicket Detector. This is a box that lights up and music when you put some things on it and not others. And using this very simple machine, lab and others have done dozens of studies showing just how good babies are learning about the world. Let me mention just one that we did with Kushner, my student. If I showed you this detector, you be likely to think to begin with that the 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 if wave a block over the top of the detector, something you wouldn’t ever think of to begin with, detector will actually activate two out of three times. Whereas, if you do likely thing, put the block on the detector, it will 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 other strategy. we did just this; we gave four year-olds this pattern of evidence, we just asked them to make it go. And sure enough, four year-olds used the evidence to wave the object on top of the detector.
Now are two things that are really interesting about this. The first is, again, remember, these are four year-olds. They’re just learning how count. But unconsciously, they’re doing these quite complicated calculations that will give them a conditional probability measure. the 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 studies we’ve just been doing in my lab, similar studies, we’ve show that four year-olds are actually better at finding an unlikely hypothesis than adults are when we give them exactly the same task. in these circumstances, the children are using statistics to out about the world, but after all, scientists also do experiments, and we wanted to if children are doing experiments. When children do experiments call it “getting into everything” or else “playing.”
And there’s been a bunch of interesting recently that have shown this playing around is really kind of experimental research program. Here’s one from Cristine Legare’s lab. What Cristine did use our Blicket Detectors. And what she did was children that yellow ones made it go and red ones didn’t, and then she showed an anomaly. And what you’ll see is that this little boy will go five hypotheses in the space of two minutes.
(Video) Boy: How about this? as the other side.
Alison Gopnik: Okay, so his first 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 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: this is his next idea. He told the experimenter do this, to try putting it out onto the location. Not working either.
Boy: Oh, because the light only to here, not here. Oh, the bottom of 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. So you put four on one to make it light up and two on this one to make it up.
AG: Okay,there’s his fifth hypothesis.
Now that is a particularly — that is a adorable and articulate little boy, but what Cristine discovered this is actually quite typical. If you look at the children play, when you ask them to explain something, what they really do is 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 be one of these brilliant butterflies who can test five hypotheses in minutes? Well, if you go back to those psychologists philosophers, a lot of them have said that babies and young children barely conscious if they were conscious at all. And I just the opposite is true. I think babies and children actually more conscious than we are as adults. Now here’s what we know how adult consciousness works. And adults’ attention 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 of thing that we’re attending to becomes extremely bright and vivid, everything else sort of goes dark. And we even know something about the 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 that makes a little part of our brain much more flexible, more plastic, better 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 young children, we see something very different. I think babies and young children seem to more of a lantern of consciousness than a spotlight of consciousness. So babies young children are very bad at narrowing down to one thing. But they’re very good at taking in lots of information lots of different sources at once. And if you actually look in brains, you see that they’re flooded with these neurotransmitters are really good at inducing learning and plasticity, and the inhibitory haven’t come on yet. So when we say that and young children are bad at paying attention, what really mean is that they’re bad at not paying attention. So they’re bad at getting rid of the interesting things that could tell them something and just looking the thing that’s important. That’s the kind of attention, the kind consciousness, that we might expect from those butterflies who are designed to learn.
Well if we 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 new situation that we’ve never been in — when we fall in love with someone new, or when we’re in new city for the first time. And what happens then is not that our consciousness contracts, it expands, that those three days in Paris seem to be more of consciousness and experience than all the months of being a walking, talking, faculty meeting-attending zombie home. And by the way, that coffee, that wonderful you’ve been drinking downstairs, actually mimics the effect of those baby neurotransmitters. So what’s like 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 waking up crying at three o’clock the morning.
(Laughter)
Now it’s good to be a grownup. I don’t want to say much about how wonderful babies are. It’s good to be grownup. We can do things like tie our shoelaces and cross the street ourselves. And it makes sense that we put a lot of into making babies think like adults do. But if what want is to be like those butterflies, to have open-mindedness, learning, imagination, creativity, innovation, maybe at least some of the time we should getting the adults to start thinking more like children.
(Applause)