What is on in this baby’s mind? If you’d asked people 30 years ago, most people, including psychologists, would have said that this baby was irrational, illogical, — that he couldn’t take the perspective of another person or understand and effect. In the last 20 years, developmental science has completely overturned picture. So in 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 that this baby be thinking about, that could be going on in mind, is trying to figure out what’s going on in mind of that other baby. After all, one of the things that’s hardest all of us to do is to figure out other people are thinking and feeling. And maybe the hardest thing of all is to figure out what other people think and feel isn’t actually exactly what we think and feel. Anyone who’s followed politics can testify to how hard that is for people to get. We wanted to know if babies and children could understand this really profound thing about other people. Now the question is: How could we them? Babies, after all, can’t talk, and if you ask a three year-old to tell what he thinks, what you’ll get is a beautiful stream of monologue about ponies and birthdays and things like that. how do we actually ask them the question?
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Well it out that the secret was broccoli. What we did — Betty Rapacholi, who was one my students, and I — was actually to give the 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 raw broccoli. (Laughter) But then Betty did was to take a little taste of from each bowl. And she would act as if she liked it or didn’t. So half the time, she acted as if she liked the and didn’t like the broccoli — just like a baby and any other person. But half 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 the crackers, and she’d go, “Eww, yuck, crackers. I tasted crackers. Eww, yuck.” So she’d act as if what she was just the opposite of what the babies wanted. did this with 15 and 18 month-old babies. And she would simply put her hand out and say, “Can you give me some?”
So the is: What would the baby give her, what they liked or what she liked? And remarkable thing was that 18 month-old babies, just barely walking and talking, would give her the crackers 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 a long time if she acted as if she liked broccoli, like they couldn’t figure this out. But then after they stared for a time, they would just 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 babies have discovered this really profound fact about human nature, that don’t always want the same thing. And what’s more, they felt they should actually do things to help other people get what they wanted.
Even more though, the fact that 15 month-olds didn’t do this suggests these 18 month-olds had learned this deep, profound fact about human nature the three months from when they were 15 months old. So children know more and learn more than we ever would have thought. And this just one of hundreds and hundreds 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 learn so much in such a short time? I mean, all, if you look at babies superficially, they seem pretty useless. And actually in ways, they’re worse than useless, because we have to put so much time energy into just keeping them alive. But if we to evolution for an answer to this puzzle of why we so much time taking care of useless babies, it turns that there’s actually an answer. If we look across many, different species of animals, not just us primates, but including other mammals, birds, even marsupials like kangaroos and wombats, turns out that there’s a relationship between how long childhood a species has and how big their brains are compared to bodies and how smart and flexible they are.
And sort of the posterbirds this idea are the birds up there. On one is a New Caledonian crow. And crows and other corvidae, ravens, and so forth, are incredibly smart birds. They’re as smart as chimpanzees in some respects. And this a bird on the cover of science who’s learned how to a tool to get food. On the other hand, have our friend the domestic chicken. And chickens and and geese and turkeys are basically as dumb as dumps. So they’re very, very at pecking for grain, and they’re not much good at doing anything else. it turns out that the babies, the New Caledonian crow babies, are fledglings. They depend on their to drop worms in their little open mouths for long as two years, which is a really long time in the life a bird. Whereas the chickens are actually mature within a couple months. So childhood is the reason why the crows end on the cover of Science and the chickens end up in soup pot.
There’s something about that long childhood that seems to be to knowledge and learning. Well what kind of explanation could we for this? Well some animals, like the chicken, seem to be 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 doing anything in particular, but they’re extremely good at learning about of different environments.
And of course, we human beings are way out the end of the distribution like the crows. We have bigger brains relative to our by far than any other animal. We’re smarter, we’re more flexible, we can learn more, we in more different environments, we migrated to cover the world even go to outer space. And our babies and children are dependent on for much longer than the babies of any other species. My son is 23. (Laughter) And least until they’re 23, we’re still popping those worms into those little open mouths.
All right, why would see this correlation? Well an idea is that that strategy, learning strategy, is an extremely powerful, great strategy for on in the world, but it has one big disadvantage. And that big disadvantage is that, until you actually do all that learning, you’re going to be helpless. So don’t want to have the mastodon charging at you and be to yourself, “A slingshot or maybe a spear might work. Which actually be better?” You want to know all that the mastodons 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 have this early period when we’re completely protected. We don’t to do anything. All 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 put to work to do things out there in the world.
So one way of thinking it is that babies and young children are like research and development division of the human species. So they’re protected blue sky guys who just have to go and learn and have 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 of thinking babies and children as being like defective grownups, we should about them as being a different developmental stage of the same species — kind of caterpillars and butterflies — except that they’re actually the brilliant butterflies who flitting around the garden and exploring, and we’re the who are inching along our narrow, grownup, adult path.
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If is 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. in fact, the baby’s brain seems to be the most powerful learning computer the planet. But real computers are actually getting to be a better. And there’s been a revolution in our understanding machine learning recently. And it all depends on the ideas of guy, the Reverend Thomas Bayes, who was a statistician mathematician in the 18th century. And essentially what Bayes did was provide a mathematical way using probability theory to characterize, describe, the that scientists find out about the world. So what scientists do is they have a hypothesis 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 that hypothesis and so on and so forth. And what Bayes showed was mathematical way that you could do that. And that mathematics at the core of the best machine learning programs that have now. And some 10 years ago, I suggested that babies might be the same thing.
So if you want to know what’s on underneath those beautiful brown eyes, I think it actually looks something like this. is Reverend Bayes’s notebook. So I think those babies actually making complicated calculations with conditional probabilities that they’re revising to out how the world works. All right, now that might seem like an taller order to actually demonstrate. Because after all, if you ask even about statistics, they look extremely stupid. How could it be that children are doing statistics?
So to this we used a machine that we have called the Detector. This is a box that lights up and plays when you put some things on it and not others. using this very simple machine, my lab and others have done of studies showing just how good babies are at about the world. Let me mention just one that we with Tumar Kushner, my student. If I showed you detector, you would be likely to think to begin with the way to make the detector go would be to put a block on top the detector. But actually, this detector works in a bit a strange way. Because if you wave a block the top of the detector, something you wouldn’t ever think of to begin with, the will actually activate two out of three times. Whereas, if do the likely thing, put the block on the detector, it will only activate two out six times. So the unlikely hypothesis actually has stronger evidence. looks as if the waving is a more effective strategy than the other strategy. we did just this; we gave four year-olds this pattern of evidence, and we just asked to make it go. And sure enough, the four year-olds used the evidence to the object on top of the detector.
Now there are two things that really interesting 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 a conditional probability measure. And the other interesting thing that they’re using that evidence to get to an idea, get to a about the 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 at finding out an unlikely hypothesis than adults are when give them exactly the same task. So in these circumstances, the are using statistics to find out about the world, after all, scientists also do experiments, and we wanted to see children are doing experiments. When children do experiments we it “getting into everything” or else “playing.”
And there’s a bunch of interesting studies recently that have shown this playing around is really a kind experimental research 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 go and red didn’t, and then she showed them an anomaly. And what you’ll see is this little boy will go through five hypotheses in the space of minutes.
(Video) Boy: How about this? Same as the side.
Alison Gopnik: Okay, so his first hypothesis has just falsified.
(Laughter)
Boy: This one lighted up, and this nothing.
AG: Okay, he’s got his experimental notebook out.
Boy: What’s 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 is his next idea. He told the experimenter do this, to try putting it out onto the other location. working either.
Boy: Oh, because the light goes only to here, here. Oh, the bottom of this box has electricity in here, this doesn’t have electricity.
AG: Okay, that’s a fourth hypothesis.
Boy: It’s lighting up. So when you put four. you put four on this one to make it light up and on this one to make it light up.
AG: Okay,there’s fifth hypothesis.
Now that is a particularly — that is a particularly adorable articulate little boy, but what Cristine discovered is this is quite typical. If you look at the way children play, when ask them to explain something, what they really do is do a of experiments. This is actually pretty typical of four year-olds.
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Well, what’s like to be this kind of creature? What’s it to be one of these brilliant butterflies who can test five hypotheses in two minutes? Well, you go back to those psychologists and philosophers, a lot of them have said that and young children were barely conscious if they were conscious at all. And I think the opposite is true. I think babies and children are actually more conscious we are as 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 that something’s relevant or important, we should pay attention to it. Our consciousness of thing that we’re attending to becomes extremely bright and vivid, and everything else sort goes dark. And we even know something about the way brain does this.
So what happens when we pay is that the prefrontal cortex, the sort of executive part of brains, sends a signal that makes a little part of our much more flexible, more 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. If look at babies and young children, we see something very different. think babies and young children seem to have more of a lantern of consciousness a spotlight of consciousness. So babies and young children are very bad at narrowing to just one thing. But they’re very good at taking in lots of information from lots of different at once. And if you actually look in their brains, you see they’re flooded with these neurotransmitters that are really good at inducing learning plasticity, and the inhibitory parts haven’t come on yet. So when we that babies and young children are bad at paying attention, what really mean is that they’re bad at not paying attention. So they’re bad at getting rid of all interesting things that could tell them something and just looking at the thing that’s important. That’s the of attention, the kind of consciousness, that we might expect from those who are designed to learn.
Well if we want think about a way of getting a taste of kind of baby consciousness as 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 we fall in love with someone new, when we’re in a new city for the first time. And happens then is not that our consciousness contracts, it expands, so those three days in Paris seem to be more of consciousness and experience than all the months of being a walking, talking, meeting-attending zombie back home. And by the way, that coffee, wonderful coffee you’ve been drinking downstairs, actually mimics the effect of baby neurotransmitters. So what’s it like to be a baby? It’s being in love in Paris for the first time you’ve had three double-espressos. (Laughter) That’s a fantastic way to be, it does tend to leave you waking up crying three o’clock in the morning.
(Laughter)
Now it’s good to be a grownup. I don’t want to say much about how wonderful babies are. It’s good to be a grownup. We can things like tie our shoelaces and cross the street ourselves. And it makes sense that we put a lot of effort into babies think like adults do. But if what we want is to be like those butterflies, have open-mindedness, open learning, imagination, creativity, innovation, maybe at least some of the time should be getting the adults to start thinking more children.
(Applause)