What is going on this baby’s mind? If you’d asked people this 30 years ago, people, including psychologists, would have said that this baby was irrational, illogical, egocentric — that he couldn’t 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 thinking the most brilliant scientists.
Let me give you just one example of this. thing that this baby could be thinking about, that could be on in his mind, is trying to figure out what’s going on the mind of that other baby. After 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 all is to figure out that what other people think and feel isn’t actually exactly like we think and feel. Anyone who’s followed politics can testify how hard that is for some people to get. We to know if babies and young children could understand really profound thing about other people. Now the question is: How could we them? Babies, after all, can’t talk, and if you a three year-old to tell you what he thinks, you’ll get is a beautiful stream of consciousness monologue about ponies birthdays and things like that. So how do we actually 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 of raw broccoli and one bowl of delicious goldfish crackers. all of the babies, even in Berkley, like the crackers don’t like the raw 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 she didn’t. So half the time, she acted as 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 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 was just the of what the babies 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 her, what they liked or what she liked? And remarkable thing was that 18 month-old babies, just barely walking and talking, would 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 long time 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 give her the crackers, what they thought everybody must like. So there are really remarkable things about this. The first one is that little 18 month-old babies have already discovered this really profound fact about nature, that we don’t always want the same thing. what’s more, they felt that they should actually do things 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 human nature in the three months from when they were 15 old. So children both know more and learn more than we ever have thought. And this is just one of hundreds and hundreds studies over the last 20 years that’s actually demonstrated it.
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The you might ask though is: Why do children learn much? And how is it possible for them to learn so much in a short time? I mean, after all, if you at babies superficially, they seem pretty useless. And actually many ways, they’re worse than useless, because we have to put so much time energy into just keeping them alive. But if we to evolution for an answer to this puzzle of why we spend so much time taking care of babies, it turns out that there’s actually an answer. If we look across many, many different of animals, not just us primates, but also including mammals, birds, even marsupials like kangaroos and wombats, it turns out that there’s a between how long a childhood a species has and how big their brains are compared their bodies and how smart and flexible they are.
And sort of the posterbirds for this idea the birds up there. On one side is a Caledonian crow. And crows and other corvidae, ravens, rooks so forth, are incredibly smart birds. They’re as smart as in some respects. And this is a bird on the cover of science who’s learned how to use tool to get food. On the other hand, we have our friend domestic chicken. And chickens and ducks and geese and turkeys basically as dumb as dumps. So they’re very, very good at pecking grain, and they’re not much good at doing anything else. Well it out that the babies, the New Caledonian crow babies, fledglings. They depend 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 are mature within a couple of months. So childhood is the reason why crows end up on the cover of Science and 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 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 be beautifully suited to pecking grain in one environment. Other creatures, like the crows, aren’t very good doing anything in particular, but they’re extremely good at about laws of different environments.
And of course, we 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 learn more, we in more different environments, we migrated to cover the world and even go to outer space. And babies and children are dependent on us for much longer than the babies of other species. My son is 23. (Laughter) And at 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, great strategy for getting on in the world, but has one 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 or maybe a spear might work. Which would actually be better?” want to know all that before the mastodons actually show up. And the way the seems to have solved that problem is with a of division of labor. So the idea is that we have early period when we’re completely protected. We don’t have to do anything. All we have do is learn. And then as adults, we can take all those that we learned when we were babies and children and actually them to work to do things out there in the world.
So one way of thinking it is that babies and young children are like research and development division of the human species. So they’re the protected blue sky guys who just to go out and learn and have good ideas, and we’re production and marketing. have to take all those ideas that we learned when we were children and actually put them use. Another way of thinking about it is instead of thinking of babies and children being like defective grownups, we should think about them as a different developmental stage of the same species — kind of like and butterflies — except that they’re actually the brilliant butterflies who are flitting the garden and exploring, and we’re the caterpillars who are along our narrow, grownup, adult path.
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If this true, if these babies are designed to learn — and this evolutionary would say children are for learning, that’s what they’re for — might expect that they would have really powerful learning mechanisms. in fact, the baby’s brain seems to be the most powerful 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, Reverend Thomas Bayes, who was a statistician and mathematician the 18th century. And essentially what Bayes did was to provide mathematical way using probability theory to characterize, describe, the that scientists find out about the world. So what do is they have a hypothesis that they think might be likely to start with. They out and test it against the evidence. The evidence makes them change that hypothesis. they test that new hypothesis and so on and so forth. And what Bayes showed a mathematical way that you could do that. And that mathematics is the core of the best machine learning programs that we have now. some 10 years ago, I suggested that babies might be doing the same thing.
So if you want know what’s going on underneath those beautiful brown eyes, think it actually looks something like this. This is Bayes’s notebook. So I think those babies are actually making calculations with conditional probabilities that they’re revising to figure out how the world works. 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 a machine that we have called Blicket Detector. This is a box that lights up and plays music 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 at 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 way to make the detector would be to put a block on top of detector. But actually, this detector works in a bit 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 activate two out of three times. Whereas, if you do the likely thing, put the block on detector, it will only activate two out of six times. So the hypothesis actually has stronger evidence. It looks as if the is a more effective strategy than the other strategy. So we did just this; we four year-olds this pattern of evidence, and we just asked them to make it go. And sure enough, four year-olds used the evidence to wave the object on top of detector.
Now there are two things that are really interesting about this. first one is, again, remember, these are four year-olds. They’re just learning how to count. unconsciously, they’re doing these quite complicated calculations that will give them conditional probability measure. And the other interesting thing is they’re using that evidence to get to an idea, get a hypothesis about the world, that seems very unlikely to with. And in studies we’ve just been doing in lab, similar studies, we’ve show that four year-olds are better at finding out an unlikely hypothesis than adults when we give them exactly the same task. So these circumstances, the children are using statistics to find about the world, but after all, scientists also do experiments, and we to see if children are doing experiments. When children do experiments we call it “getting everything” or else “playing.”
And there’s been a bunch of interesting studies recently that have shown playing around is really a kind of experimental research program. Here’s from Cristine Legare’s lab. What Cristine did was use our Blicket Detectors. And what she did show children that yellow ones made it go and red ones didn’t, then she showed them an anomaly. And what you’ll see that this little boy will go through five hypotheses in space of two minutes.
(Video) Boy: How about this? Same 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 making this up. (Laughter) I don’t know.
AG: Every scientist will that expression of despair.
(Laughter)
Boy: Oh, it’s because this needs to be like this, and needs to 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, to try it out onto the other 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 fourth hypothesis.
Boy: It’s lighting up. So 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 his fifth hypothesis.
Now is a particularly — that is a particularly adorable and articulate little boy, but what Cristine discovered this is actually quite typical. If you look at way children play, when you ask them to explain something, what they really do is do a series experiments. This is actually pretty typical of four year-olds.
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Well, what’s it to be this kind of creature? What’s it like to be of these brilliant butterflies who can test five hypotheses in two minutes? Well, if go back to those psychologists and philosophers, a lot of them have said that and young children were barely conscious if they were conscious at all. And think just the opposite is true. I think babies and children 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 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 something about the way the brain does this.
So what happens we pay attention is that the prefrontal cortex, the of executive part of our brains, sends a signal that makes little part of our brain much more flexible, more plastic, at learning, and shuts down activity in all the rest of our brains. So we have very focused, purpose-driven kind of attention. If we look at and young children, we see something very different. I babies and young children seem to have more of lantern of consciousness than a spotlight of consciousness. So babies and young children are very at narrowing down to just one thing. But they’re good at taking in lots of information from lots of different sources at once. And if you actually in their brains, you see that they’re flooded with these neurotransmitters that are really good inducing learning and plasticity, and the inhibitory parts haven’t on yet. So when we say that babies and young children are bad paying attention, what we really mean is that they’re bad at not paying attention. So they’re 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 might expect those butterflies who are designed to learn.
Well if want to think about a way of getting a 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 never been 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 consciousness contracts, expands, so 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 coffee you’ve drinking downstairs, actually mimics the effect of those baby neurotransmitters. So what’s it like be a baby? It’s like being in love in for the 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 three o’clock in the morning.
(Laughter)
Now it’s good to be a grownup. don’t want to say too much about how wonderful are. It’s good to be a grownup. We can things like tie our shoelaces and cross the street by ourselves. it makes sense that we put a lot of into making babies 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 we should be getting the adults to start thinking like children.
(Applause)