What is on in this baby’s mind? If you’d asked people this 30 ago, most people, including psychologists, would have said that this baby was irrational, illogical, egocentric — that couldn’t take the perspective of another person or understand and effect. In 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 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 his mind, is trying to figure out what’s going on in mind of that other baby. After all, one of the that’s hardest for all of us to do is to figure out what other people thinking and feeling. And maybe the hardest thing of all is to out that what other people think and feel isn’t actually exactly like what we think and feel. who’s followed politics can testify to how hard that for some people to get. We wanted to know babies and young children could understand this really profound thing about other people. Now the question is: could we ask 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 and 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 of my students, and I — actually to give the babies two 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 broccoli. (Laughter) But then what Betty did was to a little taste of food from each bowl. And would act as if she liked it or she didn’t. So the time, she acted as if she liked the crackers didn’t like the broccoli — just like a baby and any sane person. But half the time, what she would is take a little bit of the broccoli and go, “Mmmmm, broccoli. I tasted the broccoli. Mmmmm.” then she would take a little bit of the crackers, she’d go, “Eww, yuck, crackers. I tasted the crackers. Eww, yuck.” So she’d act as what she wanted was just the opposite of what the babies wanted. did this with 15 and 18 month-old babies. And then would 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 the remarkable thing that 18 month-old babies, just barely walking and talking, give her the crackers if she liked the crackers, but they would give the broccoli if she liked the broccoli. On the other hand, 15 month-olds would stare at her for long 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 the crackers, what they thought everybody must like. So there two really remarkable things about this. The first one that these little 18 month-old babies have already discovered this really profound about human nature, that we don’t always want the same thing. And what’s more, they that they should actually do things to help other people get what wanted.
Even more remarkably though, the fact that 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 they were 15 months old. So children both know more and learn more than we would have thought. And this is just one of and hundreds of 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 in such a short time? I mean, after all, if you look at babies superficially, seem pretty useless. And actually in many ways, they’re worse than useless, we have to put so much time and energy into keeping them alive. But if we turn to evolution for an to this puzzle of why we spend so much time taking care of useless babies, turns out that there’s actually an answer. If we across many, many different species of animals, not just primates, but also including other mammals, birds, even marsupials like and wombats, it turns out that there’s a relationship how long a childhood a species has and how big brains are compared to their bodies and how smart and flexible they are.
And sort the posterbirds for this idea are the birds up there. On one side a New Caledonian crow. And crows and other corvidae, ravens, rooks so forth, are incredibly smart birds. They’re as smart as chimpanzees some respects. And this is a bird on the cover science who’s learned how to use a tool to get food. On the other hand, we have friend the domestic chicken. And chickens and ducks and geese and turkeys basically as dumb as dumps. So they’re very, very good at for grain, and they’re not much good at doing anything else. Well turns out that the babies, the New Caledonian crow babies, are fledglings. They on their moms to drop worms in their little open mouths for as long as two years, is a really long time in the life of a bird. the chickens are actually mature within a couple of months. childhood is the reason why the crows end up on the cover of Science and chickens end up 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 some animals, like the chicken, seem to beautifully suited to doing just one thing very well. So they 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 of different environments.
And of course, we human beings are way out on the end of the distribution the crows. We have bigger brains relative to our bodies by than any other animal. We’re smarter, we’re more flexible, can learn more, we survive in more different environments, we to cover the world and even go to outer space. our babies and children are dependent on us for much longer than the babies of other species. My son is 23. (Laughter) And at least they’re 23, we’re still popping those worms into those little mouths.
All right, why would we see this correlation? Well an idea is that that strategy, learning strategy, is an extremely powerful, great strategy for getting in the world, but it has one big disadvantage. that one big disadvantage is that, until you actually all that learning, you’re going to be helpless. So you don’t want to have the mastodon charging at and be saying to yourself, “A slingshot or maybe a spear might work. would actually be better?” You want to know all that before the mastodons actually show up. And the the evolutions seems to have solved that problem is with a of division of labor. So the idea is that we have this period when we’re completely protected. We don’t have to anything. All we have to do is learn. And then as adults, we can all those things that we learned when we were and children and actually put them to work to do out there in the world.
So one way of thinking about it is babies and young children are like the research and development division of the human species. they’re the protected blue sky guys who just have go out and learn and have good ideas, and we’re and marketing. We have to take all those ideas we learned when we were children and actually put them use. Another way of thinking about it is instead of of babies and children as being like defective grownups, we should think about them as being a developmental stage of the same species — kind of like caterpillars and — except that they’re actually the brilliant butterflies who are flitting around the and exploring, and we’re the caterpillars who are inching along narrow, grownup, adult path.
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If 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 they would have really powerful learning mechanisms. And in fact, the baby’s brain seems be the most powerful learning computer on the planet. But real are actually getting to be a lot better. And there’s been a 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 Bayes did was to a mathematical way using probability theory to characterize, describe, the way that scientists out about the world. So what scientists do is they have a hypothesis that they think might likely to start with. They go out and test it against the evidence. The evidence makes change that hypothesis. Then they test that new hypothesis and so and so forth. And what Bayes showed was a mathematical way that could do that. And that mathematics is at the core of best machine learning programs that we have now. And some 10 ago, I suggested that babies might be doing the thing.
So if you want to know what’s going on underneath those beautiful eyes, I think it actually looks something like this. is Reverend Bayes’s notebook. So I think those babies are making complicated calculations with conditional probabilities that they’re revising to out how the world works. All right, now that might seem like an even taller order actually demonstrate. Because after all, if you ask even grownups statistics, they look extremely stupid. How could it be that children are doing statistics?
So to test this used a machine that we have called the Blicket Detector. This is a box that lights and plays music when you put some things on it and others. And using this very simple machine, my lab others have done dozens of studies showing just how good babies at learning about the world. Let me mention just one that we did Tumar Kushner, my student. If I showed you this detector, you would be likely think to begin with that the way to make the detector go 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 think of to begin with, detector will actually activate two out of three times. Whereas, if you the 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 than the other strategy. So we did just this; we gave four year-olds pattern of evidence, and we just asked them to it go. And sure enough, the four year-olds used evidence to wave the object on top of the detector.
Now there are two things that really interesting about this. The first one is, again, remember, these four year-olds. They’re just learning how to count. But unconsciously, they’re doing these quite complicated calculations will give them a conditional probability measure. And the other interesting thing that they’re using that evidence to get to an idea, get to a hypothesis about world, that seems very unlikely to begin with. And studies we’ve just been doing in my lab, similar studies, we’ve that four year-olds are actually better at finding out unlikely hypothesis than adults are when we give them the same task. So in these circumstances, the children using statistics to find out about the world, but all, scientists also do experiments, and we wanted to see children are doing experiments. When children do experiments we call “getting into 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 one from Legare’s lab. What Cristine did was use our Blicket Detectors. what she did was show children that yellow ones made it go and red didn’t, and then she showed them an anomaly. And what you’ll see is that little boy will go through five hypotheses in the 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 this one nothing.
AG: Okay, he’s his experimental notebook out.
Boy: What’s making this light up. (Laughter) I don’t know.
AG: Every scientist 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 try putting out onto the other location. Not working either.
Boy: Oh, the light goes only to here, not here. Oh, the bottom this box has electricity in here, but this doesn’t electricity.
AG: Okay, that’s a fourth hypothesis.
Boy: It’s lighting up. So when 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 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 is actually pretty of four year-olds.
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Well, what’s it like to be kind of creature? What’s it like to be one of brilliant butterflies who can test five hypotheses in two minutes? Well, if you go to those psychologists and philosophers, a lot of them have said that babies young children were barely conscious if they were conscious at all. And I just the opposite is true. I think babies and are actually more conscious than we are as adults. Now here’s we know about how adult consciousness works. And adults’ attention and consciousness look kind like a spotlight. So what happens for adults is decide that something’s relevant or important, we should pay to it. Our consciousness of that thing that we’re attending to becomes extremely bright and vivid, everything else sort of goes dark. And we even something about the way the brain does this.
So happens when we pay attention is that the prefrontal cortex, the of executive part of our brains, sends a signal that makes a little of our brain much more flexible, more plastic, better at learning, and shuts activity in all the rest of our brains. So we have very focused, purpose-driven kind of attention. If we look babies and young children, we see something very different. I think babies and young children to have more of a lantern of consciousness than spotlight of consciousness. So babies and young children are very bad narrowing down to just one thing. But they’re very good at in lots of information from lots of different sources at once. 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 when we say babies and young children are bad at paying attention, what we really mean is that they’re bad at 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 of attention, the kind consciousness, that we might expect from those butterflies who are designed learn.
Well if we want to think about a of getting a taste of that kind of baby consciousness as adults, I think the best thing think about cases where we’re put in a new that we’ve never been in before — when we fall in with someone new, or when we’re in a new city for the first time. And 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 mimics 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 waking up crying at three o’clock in the morning.
(Laughter)
Now it’s to be a grownup. I don’t want to say too much how wonderful babies are. It’s good to be a grownup. We can do things like tie shoelaces and cross the street by ourselves. And it makes sense that we put lot of effort into making babies think like adults do. But what we want is to be like those butterflies, have open-mindedness, open learning, imagination, creativity, innovation, maybe at least some of the time we should be getting adults to start thinking more like children.
(Applause)