What is going on this baby’s mind? If you’d asked people this 30 years ago, most people, including psychologists, 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 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 thing this baby could be thinking about, that could be going on in mind, is trying to figure out what’s going on in the of that other baby. After all, one of the that’s hardest for all of us to do is figure out what other people are thinking and feeling. And maybe the hardest thing of is to figure out that what other people think and feel isn’t actually exactly what we think and feel. Anyone who’s followed politics testify to how hard that is for some people to get. wanted to know if babies and young children could understand this really profound thing about other people. the question is: How could we ask them? Babies, all, can’t talk, and if you ask a three year-old to tell what 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 secret was broccoli. What we did — Betty Rapacholi, who was one of 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, in Berkley, like the crackers and don’t like the raw broccoli. (Laughter) But then Betty did was to take a little taste of food each bowl. And she would act as if she liked or she didn’t. So half the time, she acted as if she liked the crackers and didn’t the broccoli — just like a baby and any other sane person. half the time, what she would do is take a little bit of the and go, “Mmmmm, broccoli. I tasted the broccoli. Mmmmm.” And then she would a little bit of the crackers, and she’d go, “Eww, yuck, crackers. I tasted the crackers. Eww, yuck.” she’d act as if what she wanted was just opposite of what the babies wanted. We did this 15 and 18 month-old babies. And then she would simply put her hand and say, “Can you give me some?”
So the question is: What would baby give her, what they liked or what she liked? And the remarkable thing was 18 month-old babies, just barely walking and talking, would give the crackers if she liked the crackers, but they would give the broccoli if she liked the broccoli. On the hand, 15 month-olds would stare at her for a long if she acted as if she liked the broccoli, like couldn’t figure this out. But then after they stared for long time, they would just give her the crackers, what they everybody must like. So there are two really remarkable about this. The first one is that these little 18 month-old have already discovered this really profound fact about human nature, that don’t always want the same thing. And what’s more, they felt they should actually do things to help other people what they wanted.
Even more remarkably though, the fact 15 month-olds didn’t do this suggests that these 18 month-olds learned this deep, profound fact about human nature in the three months from when were 15 months old. So children both know more and learn more 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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The question you might ask is: Why do children learn so much? And how is it possible for them to learn so in such a short time? I mean, after all, if you look at babies superficially, they pretty useless. And actually in many ways, they’re worse useless, because we have to put so much time and into just keeping them alive. But if we turn to evolution an answer to this puzzle of why we spend so time taking care of useless babies, it turns out that there’s an answer. If 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 that there’s a relationship between how long a childhood a species has how big their brains are compared to their bodies and how smart and flexible they are.
And of the posterbirds for this idea are the birds up there. On one side a New Caledonian crow. And crows and other corvidae, ravens, rooks and forth, are incredibly smart birds. They’re as smart as in some respects. And this is a bird on the of science who’s learned how to use a tool to get food. On the other hand, we our friend the domestic chicken. And chickens and ducks and geese and turkeys are basically dumb as dumps. So they’re very, very good at pecking for grain, and they’re not much at doing anything else. Well it turns out that the babies, New Caledonian crow babies, are fledglings. They depend on their moms to drop worms in their little mouths for as long as two years, which is a long time in the life of a bird. Whereas the chickens are actually mature a couple of months. So childhood is the reason why the crows up on the cover of Science and the chickens up in the soup pot.
There’s something about that long childhood that to be connected to knowledge and learning. Well what of explanation could we have for this? Well some animals, like the chicken, to be beautifully suited to doing just one thing very well. So seem to be beautifully suited to pecking grain in one environment. Other creatures, like crows, aren’t very good at doing anything in particular, but they’re extremely good at learning about laws different environments.
And of course, we human beings are out on the end of the distribution like the crows. have bigger brains relative to our bodies by far than any other animal. We’re smarter, we’re more flexible, can learn more, we survive in more different environments, we migrated to cover the world and even go 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 at until they’re 23, we’re still popping those worms into those little open mouths.
All right, why 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 that one big disadvantage is that, you actually do all that learning, you’re going to helpless. So you don’t want to have the mastodon charging you and be saying to yourself, “A slingshot or maybe a spear might work. Which actually be better?” You want to know all that the mastodons actually show up. And the way the evolutions seems have solved that problem is with a kind of of labor. So the idea is that we have early period when we’re completely protected. We don’t have do anything. All we have to do is learn. And then adults, we can take all those things that we when we were babies and children and actually put to work to do things out there in the world.
So one way of thinking about it is that babies young children are like the research and development division the human species. So they’re the protected blue sky who just have to go out and learn and have ideas, and we’re production and marketing. We have to take all those ideas that we learned we were children and actually put them to use. Another way thinking about it is instead of thinking of babies and as being like defective grownups, we should think about them as being a different developmental stage of same species — kind of like caterpillars and butterflies — except that they’re actually the brilliant butterflies are flitting around the garden and exploring, and we’re the caterpillars are inching along our narrow, grownup, adult path.
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If this is true, if these are designed to learn — and this evolutionary story would say children for learning, that’s what they’re for — we might expect that would have really powerful learning mechanisms. And in fact, the baby’s brain seems to be the powerful learning computer on the planet. But real computers are actually to be a lot better. And there’s been a revolution our understanding of machine learning recently. And it all depends on ideas of this guy, the Reverend Thomas Bayes, who a statistician and mathematician in the 18th century. And essentially what Bayes was to provide a mathematical way using probability theory to characterize, describe, the that scientists find out about the world. So what scientists is they have a hypothesis that they think might be likely start with. They go out and test it against the evidence. 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 mathematics is 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 what’s going on underneath those beautiful brown eyes, I think it looks something like this. This is Reverend Bayes’s notebook. I think those babies are actually making complicated calculations with conditional that they’re revising to figure out how the world works. All right, that might seem like an even taller order to actually demonstrate. Because after all, if you ask even about statistics, they look extremely stupid. How could it be that are doing statistics?
So to test this we used a machine we have called the Blicket Detector. This is a box that lights up and plays music when you some things on it and not others. And using this very simple machine, my lab others have done dozens of studies showing just how babies are at learning about the world. Let me just one that we did with Tumar Kushner, my student. If I you this detector, you would be likely to think begin with that the way to make the detector go would be to put a block on top the detector. But actually, this detector works in a of a strange way. Because if you wave a block over top of the detector, something you wouldn’t ever think of to begin with, the detector actually activate two out of three times. Whereas, if you the likely thing, put the block on the detector, it only activate two out of six times. So the unlikely hypothesis actually has stronger evidence. It looks as the waving is a more effective strategy than the strategy. So we did just this; we gave four year-olds this pattern of evidence, and we just asked them 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 interesting 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 complicated calculations that give them a conditional probability measure. And the other interesting thing is that they’re using evidence to get to an idea, get to a hypothesis about the world, that 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 at finding out an hypothesis than adults are when we give them exactly the same task. So in circumstances, the children are using statistics to find out about the world, after all, scientists also do experiments, and we wanted to if children are doing experiments. When children do experiments we call “getting into everything” or else “playing.”
And there’s been a bunch of interesting recently that have shown this playing around is really a kind of research program. Here’s one from Cristine Legare’s lab. What Cristine did was our Blicket Detectors. And what she did was show children that yellow made it go and red ones didn’t, and then she them an anomaly. And what you’ll see is that this little boy will go through hypotheses in the space of two minutes.
(Video) Boy: about this? Same as the other side.
Alison Gopnik: Okay, so his first hypothesis has been falsified.
(Laughter)
Boy: This one lighted up, and this one nothing.
AG: Okay, he’s got experimental notebook out.
Boy: What’s making this light up. (Laughter) don’t know.
AG: Every scientist will recognize that expression of despair.
(Laughter)
Boy: Oh, it’s this needs to be like this, and this needs to be like this.
AG: Okay, two.
Boy: That’s why. Oh.
(Laughter)
AG: Now this his next idea. He told the experimenter to do this, to putting it out onto the other location. Not working either.
Boy: Oh, the light goes only to here, not here. Oh, bottom of this box has electricity in here, but this doesn’t have electricity.
AG: Okay, that’s a 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 to make it light up.
AG: Okay,there’s his fifth hypothesis.
Now that is a — that is a particularly adorable and articulate little boy, but Cristine discovered is this is actually quite typical. If you look at way children play, when you ask them to explain something, they really do is do a series of experiments. This is actually 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 one of these brilliant butterflies can test five hypotheses in two minutes? Well, if go back to those psychologists and philosophers, a lot 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 are 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 spotlight. So what happens for adults is we decide that something’s relevant important, we should pay attention to it. Our consciousness of that that we’re attending to becomes extremely bright and vivid, and else sort of goes dark. And we even know something about way the brain does this.
So what happens when we pay attention is that prefrontal cortex, the sort of executive part of our brains, sends a signal makes a little part of our brain much more flexible, plastic, better at learning, and shuts down activity in the rest of our brains. So 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 have more of a lantern of consciousness than a spotlight of consciousness. So and young children are very bad at narrowing down to just one thing. they’re very good at taking in lots of information from lots different sources at once. And if you actually look in their brains, you see they’re flooded with these neurotransmitters that are really good at learning and plasticity, and the inhibitory parts haven’t come on yet. So we say that babies and young children are bad at paying attention, what we really mean that they’re bad at not paying attention. So they’re at getting rid of all the interesting things that could tell them something and just looking at 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 of that of baby consciousness as adults, I think the best is think about cases where we’re put in a new that we’ve never been in before — when we in love with someone new, or when we’re in a new city for the time. And what happens then is not that our consciousness contracts, it expands, so that those three in Paris seem to be more full of consciousness and experience than all months of being a walking, talking, faculty meeting-attending zombie home. And by the way, that coffee, that wonderful coffee you’ve been drinking downstairs, actually the effect of those baby neurotransmitters. So what’s it like to be a baby? It’s like being in in Paris for the first time after you’ve had double-espressos. (Laughter) That’s a 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 grownup. I don’t want to say too much about how wonderful are. It’s good to be a grownup. We can do things like tie our shoelaces and cross the 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 butterflies, to have open-mindedness, open learning, imagination, creativity, innovation, at least some of the time we should be getting adults to start thinking more like children.
(Applause)