What is going on in 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 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 that baby’s thinking is like the thinking of the most brilliant scientists.
Let me give you one example of this. One thing that this baby could be thinking about, that be going on in his mind, is trying to figure out what’s going on in the mind of other baby. After all, one of the things that’s hardest for all of us to do to figure out what other people are thinking and feeling. And maybe 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 for some to get. We wanted to know if babies and young children could understand this really profound 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 to you what he thinks, what you’ll get is a beautiful stream of consciousness monologue about and birthdays and things like that. So how do we ask 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. Now all of babies, even in Berkley, like the crackers and don’t like 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 time, she acted as if she liked the crackers and didn’t like the — just like a baby and any other sane person. But the time, what she would do is take a little bit of the broccoli go, “Mmmmm, broccoli. I tasted the broccoli. Mmmmm.” And then she would take a little bit of crackers, and she’d go, “Eww, yuck, crackers. I tasted crackers. Eww, yuck.” So she’d act as if what wanted was just the opposite of what the babies wanted. We this with 15 and 18 month-old babies. And then would simply put her hand out and say, “Can you give me some?”
So the question is: would the baby give 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 her the broccoli if she the broccoli. On the other hand, 15 month-olds would stare at her for a long time if acted as if she liked the broccoli, like they couldn’t figure this out. But then after stared for a long time, they would just give her the crackers, what they thought must like. So there are two really remarkable things about this. first one is that these little 18 month-old babies have discovered this really profound fact about human nature, that we don’t want the same thing. And what’s more, they felt that should actually do things to help other people 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 three from when they were 15 months old. So children both know more and learn more than we ever 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 though is: Why do children learn so much? And how is it for them to learn so much in such a short time? I mean, after all, if you look babies superficially, they seem pretty useless. And actually in many ways, they’re worse than useless, we have to put so much time and energy into just keeping them alive. But if we to evolution for an answer to this puzzle of why we spend much time taking care of useless babies, it turns out that there’s an answer. If we look across many, many different of animals, not just us primates, but also including other mammals, birds, even marsupials like kangaroos wombats, it turns out that there’s a relationship between how long a childhood a has and how big their brains are compared to their bodies and how and flexible they are.
And sort of the posterbirds for this idea are birds up there. On one side is a New Caledonian crow. And and other corvidae, ravens, rooks and so forth, are incredibly smart birds. They’re as smart as in some respects. And this is a bird on cover of science who’s learned how to use a tool to food. On the other hand, we have our friend the domestic chicken. And chickens and ducks and geese turkeys are basically as dumb as dumps. So they’re very, good at pecking for grain, and they’re not much good doing anything else. Well it turns out that the babies, New Caledonian crow babies, are fledglings. They depend on their moms to drop in their little open mouths for as long as two years, is a really long time in the life of a bird. Whereas chickens are actually mature within a couple of months. So childhood is the reason why the crows 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. Well what 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 seem to be beautifully suited to grain in one environment. Other creatures, like the crows, aren’t very good at doing anything in particular, but they’re good at learning about laws of different environments.
And course, we human beings are way out on the end of the distribution like crows. We have bigger brains relative to our bodies by far than any animal. We’re smarter, we’re more flexible, we can learn more, we survive in more different environments, we migrated cover the world and even go to outer space. our babies and children are dependent on us for longer than the babies of any other species. My is 23. (Laughter) And at least until they’re 23, we’re popping those worms into those little open mouths.
All right, why would we see this correlation? an idea is that that strategy, that learning strategy, is an powerful, great strategy for getting on in the world, but it one big disadvantage. And 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 you and be saying to yourself, “A slingshot or a spear might work. Which would actually be better?” want to know all that before the mastodons actually 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 have early period when we’re completely protected. We don’t have do anything. All we have to do is learn. And then as adults, we can all those things that we learned when we were babies and children and put them to work to do things out there in world.
So one way of thinking about it is that babies and young children are like the research development division of the human species. So they’re the protected blue sky guys who have to go out and learn and have good ideas, we’re production and marketing. We have to take all ideas that we learned when we were children and actually put to use. Another way of thinking about it is instead thinking of babies and children as being like defective grownups, we should think about as being a different developmental stage of the same species — kind of like caterpillars and butterflies — that they’re actually the brilliant butterflies who are flitting the garden and exploring, and we’re the caterpillars who inching along our narrow, grownup, adult path.
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this is true, if these babies are designed to learn — and evolutionary story would say children are 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 to be the most powerful learning computer on the planet. But real computers are actually to be a lot better. And there’s been a revolution in 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 did was to provide mathematical way using probability theory to characterize, describe, the way scientists find out about the world. So what scientists do is they have a hypothesis that think might be likely to start with. They go out and test it the evidence. The evidence makes them change that hypothesis. they test that new hypothesis and so on and so forth. what Bayes showed was a mathematical way that you could do that. And that is at the core of the best machine learning programs that we now. And some 10 years ago, I suggested that babies might doing the same thing.
So if you want to know what’s going on underneath those beautiful eyes, I think it actually looks something like this. This Reverend Bayes’s notebook. So I think those babies are actually making calculations with conditional probabilities that they’re revising to figure how the world works. All right, now that might seem like an even order to actually demonstrate. Because after all, if you ask even grownups about statistics, they look stupid. How could 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 and not others. And using this very simple machine, my lab and others have done dozens studies showing just how good babies are at learning about the world. Let me mention just that we did with Tumar Kushner, my student. If I showed you this detector, would be likely to think to begin with that the to make the detector go would be to put a on top of the detector. But actually, this detector works in a bit of a way. Because if you wave a block over the top of the detector, you wouldn’t ever think of to begin with, the detector actually activate two out of three times. Whereas, if you do the thing, put the block on the detector, it will only two out of six times. So the unlikely hypothesis has stronger evidence. It looks as if 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 just asked them to make it go. And sure enough, the four year-olds used the evidence wave the object on top of the detector.
Now there are two things that are really about this. The first one is, again, remember, these are year-olds. They’re just learning how to count. But unconsciously, they’re doing these quite complicated calculations that will give them conditional probability measure. And the other interesting thing is that they’re that evidence to get to an idea, get to a hypothesis about the world, seems very unlikely to begin with. And in studies we’ve just doing in my lab, similar studies, we’ve show that year-olds are actually better at finding out an unlikely hypothesis than adults are when we give them exactly same task. So 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 we it “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 experimental research program. Here’s one from Legare’s lab. What Cristine did was 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 through five hypotheses in the space of two minutes.
(Video) Boy: How this? Same as the other side.
Alison Gopnik: Okay, so first hypothesis 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 needs to be like this, and this needs to be like this.
AG: Okay, two.
Boy: That’s why. Oh.
(Laughter)
AG: Now this is his next idea. told the experimenter to do this, to try putting it out the other location. Not working either.
Boy: Oh, because light goes 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 on this one to make it light up and two on this one to it light 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 is this is quite typical. If you look at the way children play, when you ask them to something, what they really do is do a series of experiments. This actually pretty typical of four year-olds.
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Well, what’s like 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 of them have said that and young children were barely conscious if they were conscious all. And I think just the opposite is true. I think babies and are actually more conscious than we are as adults. Now here’s what we about how adult consciousness works. And adults’ attention and consciousness look kind of like spotlight. So what happens for adults is we decide that something’s relevant or important, we pay attention to it. Our consciousness of that thing that we’re attending to becomes extremely and vivid, and everything else sort of goes dark. And we know something about the way the brain does this.
So what when we pay attention is that the prefrontal cortex, sort of executive part of our brains, sends a that makes a little part of our brain much more flexible, plastic, better at learning, and shuts down activity in all the rest of brains. So we have a very focused, purpose-driven kind of attention. we look at babies and young children, we see very different. I think babies and young children seem have more of a lantern of consciousness than a spotlight of consciousness. So babies and young are very bad at narrowing down to just one thing. But they’re very good at taking in lots of from lots of different sources at once. And if you actually look in their brains, you see 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 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 tell them something and just looking at the thing that’s important. That’s the kind of attention, the kind of consciousness, we might expect from those butterflies who are designed to learn.
Well if we want to about a way of getting a taste of that kind of baby consciousness adults, I think the best thing is think about cases where we’re put a new situation that we’ve never been in before — when fall in love with someone new, or when we’re in new city for the first time. And what happens then not that our consciousness contracts, it expands, so that those three days in seem to be more full of consciousness and experience than all the of being a walking, talking, faculty meeting-attending zombie back home. And the way, that coffee, that wonderful coffee you’ve been downstairs, actually mimics the effect of those baby neurotransmitters. what’s it like to be a baby? It’s like being love in Paris for the first time after you’ve had double-espressos. (Laughter) That’s a fantastic way to be, but does tend to leave you waking up crying at o’clock in the morning.
(Laughter)
Now it’s good to be a grownup. don’t want to say too much about how wonderful babies are. It’s to be a grownup. We can do things like tie our and cross the street by ourselves. And it makes sense that we put lot of effort into making babies think like adults do. But if what we want is be like those butterflies, to have open-mindedness, open learning, imagination, creativity, innovation, maybe at least some of the time we be getting the adults to start thinking more like children.
(Applause)