What is going in this baby’s mind? If you’d asked people this 30 ago, most people, including psychologists, would have said that this was irrational, illogical, egocentric — that he couldn’t take the of another person or understand cause and effect. In 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 his mind, is trying to out what’s going on in the mind of that other baby. After all, one the things that’s hardest for all of us to is to figure out what other people are thinking and feeling. And the hardest thing of all is to figure out that what other think and feel isn’t actually exactly like what we and feel. Anyone who’s followed politics can testify to how hard that is some people to get. We wanted to know if babies and young children could understand this profound thing about 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 stream consciousness monologue about ponies and birthdays and things like that. So how do actually ask them the question?
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Well it turns out that the secret broccoli. What we did — Betty Rapacholi, who was of my students, and I — was actually to the babies two bowls of food: one bowl of raw broccoli one bowl of delicious goldfish crackers. Now all of babies, even in Berkley, like the crackers and don’t the raw broccoli. (Laughter) But then what Betty did was to take a taste of food from each bowl. And she would as if she liked it or she didn’t. So half the time, she acted as if she liked crackers and didn’t like the broccoli — just like a baby and any 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. I the crackers. Eww, yuck.” So she’d act as if she wanted was just the opposite of what the wanted. We did this with 15 and 18 month-old babies. And she would simply put her hand out and say, “Can you give some?”
So the question is: What would the baby give her, what they liked or she liked? And the remarkable thing was that 18 month-old babies, just walking and talking, would give her the crackers if liked the crackers, but they would give her the broccoli if liked the broccoli. On the other hand, 15 month-olds stare at her for a long time if she acted as if she liked the broccoli, like 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 two really remarkable things about this. The first one is that these little 18 month-old have already discovered this really profound fact about human nature, that we don’t always want the 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 that 15 month-olds didn’t do this suggests that these 18 month-olds had learned this deep, profound fact about human in the three months from when they were 15 months old. So children both know and 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 it.
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The question you might ask though is: Why do children so much? And how is it possible for them to learn so much such a short time? I mean, after all, if look at babies superficially, they seem pretty useless. And in many ways, they’re worse than useless, because we to put so much time and energy into just them alive. But if we turn to evolution for an answer to this puzzle of why we spend much time taking care of useless babies, it turns out there’s actually an answer. If we look across many, many species of animals, not just us primates, but also other 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 their brains are compared to their bodies and how smart and flexible they are.
And sort of the for this idea are the birds up there. On one side is a Caledonian crow. And crows and other corvidae, ravens, rooks and so forth, are incredibly smart birds. They’re smart as chimpanzees in some respects. And this is a on the cover of science who’s learned how to use tool to get food. On the other hand, we have our 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 good at doing anything else. Well it turns out the babies, the New Caledonian crow babies, are fledglings. depend on their moms to drop worms in their open mouths for as long as two years, which a really long time in the life of a bird. Whereas the are actually mature within a couple of months. So childhood is the reason the crows end up on the cover of Science and the chickens end in the soup pot.
There’s something about that long childhood seems to be connected to knowledge and learning. Well kind of explanation could we have for this? Well animals, like the chicken, seem to be beautifully suited to doing just thing very well. So they seem to be beautifully to pecking grain in one environment. Other creatures, like the crows, aren’t good at doing anything in particular, but they’re extremely good at about laws of different environments.
And of course, we human are way out on the end of the distribution like crows. We have bigger brains relative to our bodies by far any other animal. We’re smarter, we’re more flexible, we can learn more, we survive in more different environments, migrated to cover the world and even go to outer space. And our and children are dependent on us for much longer 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, would we see this correlation? Well an idea is that strategy, that learning strategy, is an extremely powerful, great 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. you don’t want to have the mastodon charging at you be saying to yourself, “A slingshot or maybe a spear work. Which would actually be better?” You want to know all that before the actually show up. And the way the evolutions seems to have solved that is with a kind of division of labor. So the idea is that we this early period when we’re completely protected. We don’t have to do anything. we have to do is learn. And then as adults, we take all those things 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 about it is that babies and young children are like the research and division of the human species. So they’re the protected blue sky guys who just have to out and learn and have good ideas, and we’re production marketing. We have to take all those ideas that we learned when were children and actually put them to use. Another way of about it is instead of thinking of babies and children as being like defective grownups, we should think them as being a different developmental stage of the same species — kind of like and butterflies — except that they’re actually the brilliant butterflies who flitting around the garden and exploring, and we’re the caterpillars who 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 really powerful learning mechanisms. And fact, the baby’s brain seems to be the most powerful learning computer on the planet. But real are actually getting to be a lot better. And there’s been revolution in our understanding of machine learning recently. And it all depends the ideas of this guy, the Reverend Thomas Bayes, who was statistician and mathematician in the 18th century. And essentially what did was to provide a mathematical way using probability to characterize, describe, the way that scientists find out about the world. So what scientists is they have a hypothesis that they think might be likely to start with. They go out test it against the evidence. The evidence makes them change that hypothesis. Then they test new hypothesis and so on and so forth. And Bayes showed was a mathematical way that you could do that. And mathematics is at the core of the best machine learning programs that we have now. some 10 years ago, I suggested that babies might be doing the thing.
So if you want to know what’s going on underneath beautiful brown eyes, I 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. All right, now might seem like an even taller order to actually demonstrate. after all, if you ask even grownups about statistics, they look extremely stupid. How it be that children are doing statistics?
So to test this we used a machine that have called the Blicket Detector. This is a box lights up and plays music when you put some things on it 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 mention one that we did with Tumar Kushner, my student. If I you this detector, you would be likely to think to begin with that the way to make the go would be to put a block on top of the detector. But actually, this works in a bit of a strange way. Because if you wave a block the top of the detector, something you wouldn’t ever of to begin with, the detector will actually activate two of three times. Whereas, if you do the likely thing, the block on the detector, it will only activate two out six times. So the unlikely hypothesis actually has stronger evidence. It looks as if waving is a more effective strategy than the other strategy. So we did this; we gave four year-olds this pattern of evidence, and just asked them to make it go. And sure enough, the four year-olds used the evidence to the object on top of the detector.
Now there two things that are really interesting about this. The first one is, again, remember, are four year-olds. They’re just learning how to count. 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 to get to an idea, get to a hypothesis about world, that seems very unlikely to begin with. And in studies we’ve just been doing my lab, similar studies, we’ve show that four year-olds are actually better at finding out an unlikely hypothesis adults are when we give them exactly the same task. in these circumstances, the children are using statistics to find out about the world, but after all, scientists do experiments, and we wanted to see if children are doing experiments. children do experiments we call it “getting into everything” or else “playing.”
And there’s 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 she did was show children that yellow ones made it go and ones didn’t, and then she showed them an anomaly. And what you’ll is that this little boy will go through five in the space of two minutes.
(Video) Boy: How about this? Same the other side.
Alison Gopnik: Okay, so his first hypothesis just 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) I don’t know.
AG: Every scientist will recognize expression of despair.
(Laughter)
Boy: Oh, it’s because this needs to be like this, and this needs be like this.
AG: Okay, hypothesis two.
Boy: That’s why. Oh.
(Laughter)
AG: Now this is his next idea. He told the to do this, to try putting it out onto other location. Not working either.
Boy: Oh, because the light goes only here, not here. Oh, the bottom of this box has 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 put four on this one to make it light and two on this one to make it light up.
AG: Okay,there’s fifth hypothesis.
Now that is a particularly — that is particularly adorable and articulate little boy, but what Cristine discovered is this is actually quite typical. If you at the way children play, when you ask them to explain something, what they really do is do series of experiments. This is actually pretty typical of year-olds.
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Well, what’s it like to be this of creature? What’s it like to be one of these brilliant butterflies can test five hypotheses in two minutes? Well, if you go back to those and philosophers, a lot of them have said that babies young children were barely conscious if they were conscious at all. I think just the opposite is true. I think and children are actually more conscious than we are adults. Now here’s what we know about how adult works. And adults’ attention and consciousness look kind of a spotlight. So what happens for adults is we decide that something’s relevant important, we should pay attention to it. Our consciousness of that thing that we’re attending becomes extremely bright and vivid, and everything else sort of goes dark. we even know something about the way the brain this.
So what happens when we pay attention is that prefrontal cortex, the sort of executive part of our brains, a signal that makes a little part of our much more flexible, more plastic, better at learning, and shuts down in all the rest of our brains. So we have a very focused, purpose-driven kind of attention. If look at babies and young children, we see something very different. I think babies and young seem to have more of a lantern of consciousness than a of consciousness. So babies and young children are very 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, you see that they’re flooded with these that are really good at inducing learning and plasticity, and inhibitory parts haven’t come on yet. So when we say that babies and young are bad at paying attention, what we really mean is that they’re at not paying attention. So they’re bad at getting rid of the interesting things that could tell them something and looking at the thing that’s important. That’s the kind attention, the kind of consciousness, that we might expect from those butterflies who are designed to learn.
Well we want to think about a way of getting a taste that kind of baby consciousness as adults, I think the thing is think about cases where we’re put in a new that we’ve never been in before — when we fall in love with new, or when we’re in a new city for the time. And what happens then is not that our consciousness contracts, it expands, that those three days in Paris seem to be more full of consciousness experience than all the months of being a walking, talking, faculty meeting-attending zombie back home. by the way, that coffee, that wonderful coffee you’ve been drinking downstairs, actually mimics the effect of those neurotransmitters. So what’s it like to be a baby? It’s like in love in Paris for the first time after you’ve had three double-espressos. (Laughter) That’s a fantastic 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 too about how wonderful babies are. It’s good to be grownup. We can do things like tie our shoelaces and cross the street by ourselves. And it sense that we put a lot of effort into making think like adults do. But if what we want is to be like those butterflies, to have open-mindedness, learning, imagination, creativity, innovation, maybe at least some of the we should be getting the adults to start thinking like children.
(Applause)