What is going on in this baby’s mind? you’d asked people this 30 years ago, most people, psychologists, would have said that this baby was irrational, illogical, — that he couldn’t take the perspective of another person understand cause and effect. In the last 20 years, science has completely overturned that picture. So in some ways, we that this baby’s thinking is like the thinking of the brilliant scientists.
Let me give you just one example of this. One thing that this baby could 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, of the things that’s hardest for all of us to do to figure out what other people are thinking and feeling. maybe the hardest thing of all is to figure out what other people think and feel isn’t actually exactly like what think 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 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 tell you what he thinks, what you’ll get is beautiful stream of consciousness monologue about ponies and birthdays and things like that. So how do actually ask them the question?
footnote
Well it turns that the secret was broccoli. What we did — Rapacholi, who was one 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 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 the time, she acted as if she liked the crackers and didn’t like the broccoli — like a baby and any other sane person. But the time, what she would do is take a little of the broccoli and go, “Mmmmm, broccoli. I tasted the broccoli. Mmmmm.” And then she take 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 the of what the babies wanted. We did this with 15 18 month-old babies. And then she would simply put her hand out say, “Can you give me some?”
So the question is: What would baby give her, what they liked or what she liked? the remarkable thing was that 18 month-old babies, just barely walking and talking, would give her 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 a long time if she acted as if she liked the broccoli, they couldn’t figure this out. But then after they stared a long time, they would just give her the crackers, what they thought everybody like. So there are two really remarkable things about this. The first one is that these 18 month-old babies have already discovered this really profound fact about nature, that we don’t always want the same thing. And what’s more, felt that they should actually do things to help people get what they wanted.
Even more remarkably though, fact that 15 month-olds didn’t do this suggests that these 18 month-olds had learned this deep, profound fact human nature in the three months from when they 15 months old. So children both know more and learn than we ever would have thought. And this is one of hundreds and hundreds of studies over the last 20 years that’s actually it.
footnote
The question you might ask though is: Why do children so much? And how is it possible for them to learn so much in a short time? I mean, after all, if you look at babies superficially, they seem pretty useless. actually in many ways, they’re worse than useless, because 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 of useless babies, it turns out that there’s actually an answer. If we look many, many different species of animals, not just us primates, but also other mammals, birds, even marsupials like kangaroos and wombats, it turns out there’s a relationship between how long a childhood a species has and big their brains are compared to their bodies and how smart flexible they are.
And sort of the posterbirds for idea are the birds up there. On one side is New Caledonian crow. And crows and other corvidae, ravens, rooks 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 get food. the other hand, we have our friend the domestic chicken. chickens and ducks and geese and turkeys are basically as dumb as dumps. they’re very, very good at pecking for grain, and they’re not good at doing anything else. Well it turns out that the babies, the New Caledonian babies, are fledglings. They depend on their moms to drop in their little open mouths for as long as two years, which a really long time in the life of a bird. Whereas the chickens are actually within a couple of months. So childhood is the reason why the crows end up on the cover Science and the chickens end up in the soup pot.
There’s something about 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 be beautifully suited to just one thing very well. So they seem to be suited to pecking grain in one environment. Other creatures, like the crows, aren’t very good at doing anything particular, but they’re extremely good at learning about laws of different environments.
And of course, we beings are way out on the end of the distribution like the crows. We bigger brains relative to our bodies by far than any animal. We’re smarter, we’re more flexible, we can learn more, survive in more different environments, we migrated to cover world and even go to outer space. And our babies children are dependent on us for much longer than the babies of any other species. son is 23. (Laughter) And at least until they’re 23, we’re still popping those worms into little open mouths.
All right, why 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 one 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 have the mastodon charging at you and be saying to yourself, “A slingshot or maybe spear might work. Which would actually be better?” You want know all that before the mastodons actually show up. And the the evolutions seems to have solved that problem is with a kind of division of labor. the idea is that we have this early period when we’re completely protected. don’t have to do anything. All we have to do is learn. then as 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 is that 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 production marketing. We have to take all those ideas that we learned when we were children actually put them to use. Another way of thinking about it is of thinking of babies and children as being like grownups, we should think about them as being a different developmental stage of the 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 who are inching along narrow, grownup, adult path.
footnote
If this is true, if these are designed to learn — and this evolutionary story say children are for learning, that’s what they’re for — we might expect that they would have 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 our of machine learning recently. And it all depends on the ideas of this guy, the Thomas Bayes, who was a statistician and mathematician in 18th century. And essentially what Bayes did was to provide a way using probability theory to characterize, describe, the way that scientists find out about the world. So what do is they have a hypothesis that they think be likely to start with. They go out and test it against the evidence. The evidence makes them that hypothesis. Then they test that new hypothesis and so on and forth. And what Bayes showed was a mathematical way you could do that. And that mathematics is at the of the best machine learning programs that we have now. And 10 years ago, I suggested that babies might be doing the same thing.
So if want to know what’s going on underneath those beautiful brown eyes, I it actually looks something like this. This is Reverend Bayes’s notebook. So think those babies are actually making complicated calculations with conditional probabilities that they’re revising to figure how the world works. All right, now that might like an even taller order to actually demonstrate. Because after all, if you even grownups about statistics, they look extremely stupid. How it be that children are doing statistics?
So to test this used a machine that we have called the Blicket Detector. This is box that lights up and plays music when you put things on it and not others. And using this very simple machine, lab and others have done dozens of studies showing just how good babies at learning about the world. Let me mention just one that did with Tumar Kushner, my student. If I showed you this detector, you would likely to think to begin with that the way make the detector go would be to put a block on top of detector. But actually, this detector works in a bit of a strange way. Because if you wave a over the top of the detector, something you wouldn’t ever think of to with, the detector will actually activate two out of three times. Whereas, you do the likely thing, put the block on the detector, it only activate two out of six times. So the unlikely hypothesis actually stronger evidence. It looks as if the waving is a effective strategy than the other strategy. So we did just this; we four year-olds this pattern of evidence, and we just asked them to make go. And sure enough, the four year-olds used the to wave the object on top of the detector.
Now there are two things that are really interesting this. The first one is, again, remember, these are four year-olds. They’re just how to count. But unconsciously, they’re doing these quite calculations that will give them a conditional probability measure. the other interesting thing is that they’re using that evidence to get to an idea, get a hypothesis about the world, that seems very unlikely to with. And in studies we’ve just been doing in lab, similar studies, we’ve show that four year-olds are better at finding out an unlikely hypothesis than adults are when we give exactly 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 if children are experiments. When children 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 was use our Blicket Detectors. And she did was show children that yellow ones made it and red ones didn’t, and then she showed them an anomaly. And what you’ll see that this little boy will go through five hypotheses in space of two minutes.
(Video) Boy: How about this? Same as the side.
Alison Gopnik: Okay, so his first hypothesis has just been falsified.
(Laughter)
Boy: This one lighted up, this one nothing.
AG: Okay, he’s got his experimental 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 experimenter to do this, to try putting it out the other location. Not working either.
Boy: Oh, because the goes only to here, not here. Oh, the bottom of this box 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 put four on this one to make it light up and two on one 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 the way children play, when you ask them to explain something, what they really do is a series of experiments. This is actually pretty typical of four year-olds.
footnote
Well, what’s it like be this kind of creature? What’s it like to be one of these brilliant butterflies who test five hypotheses in two minutes? Well, if you go to those psychologists and philosophers, a lot of them have that babies and young children were barely conscious if were conscious at all. And I think just the opposite is true. think babies and children are actually more conscious than we as adults. Now here’s what we know about how consciousness works. And adults’ attention and consciousness look kind of like a spotlight. So what happens for adults we decide that something’s relevant or important, we should pay attention to it. Our consciousness of that thing we’re attending to becomes extremely bright and vivid, and everything else sort of dark. And we even know something about the way the does this.
So what happens when we pay attention is that the prefrontal cortex, the of executive part of our brains, sends a signal that a little part of our brain much more flexible, plastic, better at learning, and shuts down activity in all the rest of our brains. we have a very focused, purpose-driven kind of attention. we look at babies and young children, we see something different. I think babies and young children seem to have of a lantern of consciousness than a spotlight of consciousness. So babies and young children are very bad narrowing down to just one thing. But they’re very good taking in lots of information from lots of different at once. And if you actually look in their brains, you see that they’re flooded with these neurotransmitters that really good at inducing learning and plasticity, and the parts haven’t come on yet. So when we say that babies young children are bad at paying attention, what we mean is that they’re bad at not paying attention. they’re bad at getting rid of all 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 those butterflies who are designed to learn.
Well if want to think about a way of getting a taste of kind of baby consciousness as adults, I think the best is think about cases where we’re put in a situation that we’ve never been in before — when we fall love with someone new, or when we’re in a new city for first time. And what happens then is not that consciousness contracts, it expands, so that those three days Paris seem to be more full of consciousness and experience all the months of being a walking, talking, faculty meeting-attending back 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 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 three o’clock in the morning.
(Laughter)
Now it’s good be a grownup. I don’t want to say too much about how wonderful babies are. It’s good be a grownup. We can do things like tie our shoelaces and cross the street by ourselves. it makes sense that we put a lot of into making babies think like adults do. But if what we is to be like those butterflies, to have open-mindedness, learning, imagination, creativity, innovation, maybe at least some of time we should be getting the adults to start thinking like children.
(Applause)