What is going on in baby’s mind? If you’d asked people this 30 years ago, most people, including psychologists, would said that this baby was irrational, illogical, egocentric — that he couldn’t the perspective of another person or understand cause and effect. In last 20 years, developmental science has completely overturned that picture. in some ways, we think that this baby’s thinking is like the thinking of most brilliant scientists.
Let me give you just one example this. One thing that this baby could be thinking about, could be going on in his 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 to out what other people are thinking and feeling. And maybe the thing of all is to figure out that what other people and feel isn’t actually exactly like what we think feel. Anyone who’s followed politics can testify to how hard that is some people to get. We wanted to know if babies young children could understand this really profound thing about other people. Now question is: How could we ask them? Babies, after all, can’t talk, if you ask a three year-old to tell you he thinks, what you’ll get is a beautiful stream consciousness monologue about ponies and birthdays and things like that. how do we actually ask them the question?
footnote
Well turns out that the secret was broccoli. What we did — Betty Rapacholi, was one of my students, and I — was actually to give the two bowls of food: one bowl of raw broccoli and one bowl delicious goldfish crackers. Now 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 of food from each bowl. And she would act as she liked it or she didn’t. So half the time, she acted as if she the crackers and didn’t like the broccoli — just like baby and any other sane person. But half the time, what she do is take a little bit of the broccoli go, “Mmmmm, broccoli. I tasted the broccoli. Mmmmm.” And she would take a little bit of the 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 she simply put her hand out and say, “Can you me some?”
So the question is: What would the baby give her, they liked or what she liked? And the remarkable thing was that 18 month-old babies, just barely walking talking, would give her the crackers if she liked the crackers, but they would give her the broccoli 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 broccoli, like they couldn’t figure this out. But then they stared for a long time, they would just give her the crackers, what they thought everybody like. So there are two really remarkable things about this. first one is that these little 18 month-old babies already discovered this really profound fact about human 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 remarkably though, the fact 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 more and learn than we ever would have thought. And this is just one hundreds and hundreds of studies over the last 20 years that’s demonstrated it.
footnote
The question you might ask is: Why do children learn so much? And how is it possible them to learn so much in such a short time? I mean, after all, if you at babies superficially, they seem pretty useless. And actually in ways, they’re worse than useless, because we have to put so time and energy into just keeping them alive. But if we turn to evolution an answer to this puzzle of why we spend so much time taking care of useless babies, it out that there’s actually an answer. If we look across many, many species of animals, not just us primates, but also including other mammals, birds, even like kangaroos and wombats, it turns out that there’s a relationship between long a childhood a species has and how big their are compared to their bodies and how smart and flexible they are.
And sort of the posterbirds this idea are the birds up there. On one side is a New Caledonian crow. And and other corvidae, ravens, rooks and so forth, are incredibly birds. They’re as smart as chimpanzees in some respects. And is a bird on the cover of science who’s learned how to a tool to get food. On the other hand, we have our friend domestic chicken. And chickens and ducks and geese and turkeys are basically as as dumps. So they’re very, very good at pecking grain, and they’re not much good at doing anything else. Well it turns out the babies, the New Caledonian crow babies, are fledglings. They depend on their moms to drop worms in little open mouths for as long as two years, which is a really long in the life of a bird. Whereas the chickens are actually mature within 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 seems be connected to knowledge and learning. Well what kind of explanation could we have for this? some animals, like the chicken, seem to be beautifully suited to doing just one thing very well. So seem to be beautifully suited to pecking grain in environment. Other creatures, like the crows, aren’t very good at doing 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 any other animal. We’re smarter, we’re more flexible, we can learn more, we survive in different environments, we migrated to cover the world and even go to outer space. And babies and children are dependent on us for much than the babies of any other species. My son is 23. (Laughter) at least until they’re 23, we’re still popping those worms into those open mouths.
All right, why would we see this correlation? Well idea is that that strategy, that learning strategy, is an extremely powerful, strategy for getting on in the world, but it has big disadvantage. And that one big disadvantage is that, until you do all that learning, you’re going to be helpless. So you don’t want to have the charging at you and be saying to yourself, “A slingshot or a spear might work. Which would actually be better?” You want to know all before the mastodons actually show up. And the way evolutions seems to have solved that problem is with a kind division of labor. So the idea is that we have this early period we’re completely protected. We don’t have to do anything. All we have to do is learn. And then adults, we can take all those things that we learned when we babies and children and actually put them to work to things out there in the world.
So one way of thinking about it is that babies and children are like the research and development division of the human species. they’re the protected blue sky guys who just have to go out and learn and good ideas, and we’re production and marketing. We have to all those ideas that we learned when we were and actually put them to use. Another way of thinking about it is instead thinking of babies and children as being like defective grownups, should think about them as being a different developmental of the same species — kind of like caterpillars and butterflies — that they’re actually the brilliant butterflies who are flitting around the garden and exploring, and we’re the who are inching along our narrow, grownup, adult path.
footnote
If is true, if these babies are designed to learn — and this story would say children are for learning, that’s what they’re — we might expect that they would have really powerful mechanisms. And in fact, the baby’s brain seems to the most powerful learning computer on the planet. But real computers are actually getting to be lot better. And there’s been a revolution in our of machine learning recently. And it all depends on the ideas of this guy, the Reverend Bayes, who was a 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 find out about the world. So what scientists do is they have a that they think might be likely to start with. They go 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 you could do that. And that is at the core of the best machine learning programs that have now. And some 10 years ago, I suggested that might be doing the same 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 complicated calculations with conditional probabilities that they’re revising to figure how the world works. All right, now that might seem like an even taller order to demonstrate. Because after all, if you ask even grownups statistics, they look extremely stupid. How could it be that children doing statistics?
So to test this we used a machine that we have called the Blicket Detector. This a box that lights up and plays music when you put some things it and not others. And using this very simple machine, my lab and have done dozens of studies showing just how good babies are at learning the world. Let me mention just one that we did with Tumar Kushner, student. If I showed you this detector, you would be to think to begin with that the way to make the detector go would be to put block on top of the detector. But actually, this detector works a bit of a strange way. Because if you a block over the top of the detector, something you wouldn’t ever of to begin with, the detector will actually activate two out of times. Whereas, if you do the likely thing, put the on the detector, it will only activate two out of times. So the unlikely hypothesis actually has stronger evidence. It looks if the waving is a more effective strategy than other strategy. So we did just this; we gave four year-olds pattern of evidence, and we just asked them to make it go. sure enough, the four year-olds used the evidence to the object on top of the detector.
Now there are two things are 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 that will them a conditional probability measure. And the other interesting thing that they’re using that evidence to get to an idea, to a hypothesis about the world, that seems very 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 out an unlikely hypothesis than adults are when we give exactly the same task. So in these circumstances, the are using statistics to find out about the world, but after all, also do experiments, and we wanted to see if children are doing experiments. When do experiments we call it “getting into everything” or “playing.”
And there’s been a bunch of interesting studies recently that have this playing around is really a kind of experimental program. Here’s one from Cristine Legare’s lab. What Cristine did use our Blicket Detectors. And what she did was children that yellow ones made it go and red ones didn’t, then she showed them an anomaly. And what you’ll see is that this little will go through five hypotheses in the space of two minutes.
(Video) Boy: about this? Same as the other side.
Alison Gopnik: Okay, so first hypothesis has just been falsified.
(Laughter)
Boy: This one lighted up, this one nothing.
AG: Okay, he’s got his experimental notebook out.
Boy: What’s this light up. (Laughter) I don’t know.
AG: Every scientist will recognize that expression despair.
(Laughter)
Boy: Oh, it’s because this needs to 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. He the experimenter to do this, to try putting it out onto other location. Not working either.
Boy: Oh, because the light goes only to here, here. Oh, the bottom of this box has electricity in here, but this doesn’t electricity.
AG: Okay, that’s a fourth hypothesis.
Boy: It’s lighting up. when you put four. So you put four on this one to make light up and two on this one to make it up.
AG: Okay,there’s his fifth hypothesis.
Now that is a particularly — is a particularly adorable and articulate little boy, but what discovered is this is actually quite typical. If you look the way children play, when you ask them to something, what they really do is do a series of experiments. This is actually pretty typical four year-olds.
footnote
Well, what’s it like to be kind of creature? What’s it like to be one of these butterflies who can test five hypotheses in two minutes? Well, you go back to those psychologists and philosophers, a lot of have said that babies and young children were barely conscious if were conscious at all. And I think just the opposite is true. I think babies children are actually more conscious than we are as adults. Now here’s what we about how adult consciousness works. And adults’ attention and consciousness kind of like a spotlight. So what happens for is we decide that something’s relevant or important, we should pay attention it. Our consciousness of that thing that we’re attending becomes extremely bright and vivid, and everything else sort of goes dark. And we even know something about way the brain does this.
So what happens when we pay is that the prefrontal cortex, the sort of executive part of our brains, sends a signal that a little part of our brain much more flexible, more plastic, better learning, and shuts down activity in all the rest of our brains. So we a very focused, purpose-driven kind of attention. If we look babies and young children, we see something very different. think 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 very good at taking in of information from lots of different sources at once. if you actually look in their brains, you see that they’re flooded with neurotransmitters that are really good at inducing learning and plasticity, the inhibitory parts haven’t come on yet. So when say that babies and young children are bad at paying attention, what we really mean is they’re bad at not paying attention. So they’re bad at getting of all the interesting things that could tell them and just looking at the thing that’s important. That’s kind of attention, the kind of consciousness, that we might from those butterflies who are designed to learn.
Well we want to think about a way of getting a taste of kind of baby consciousness as adults, I think the best thing is about cases where we’re put in a new situation that we’ve never been in before — when we in love with someone new, or when we’re in a new city the first time. And what happens then is not that consciousness contracts, it expands, so that those three days in Paris seem to be more of consciousness and experience than all the months of being walking, talking, faculty meeting-attending zombie back 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 like to be a baby? It’s like being in love in Paris the first time after you’ve had three double-espressos. (Laughter) That’s a fantastic way to be, but it does 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 too much about how wonderful babies are. It’s good be a grownup. We can do things like tie our shoelaces 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 to be like those butterflies, to have open-mindedness, open learning, imagination, creativity, innovation, maybe at least some of time we should be getting the adults to start thinking like children.
(Applause)