How a Chimp Can Outsmart Your Child

Psychologist
Our ability to learn from others is crucial for the evolution of cumulative technologies, but often paralyzes our causal intuition.
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TRANSCRIPT

Question: Why are monkeys capable of using rudimentary tools, but not more modern technology?
 

Laurie Santos: Primate researchers are also a little disingenuous when they talk about primate tool-use because the kinds of tools that primates use tend to really impress us. First of all, they use tools, which we didn’t think they did, you know, over 40 years ago. Now we see evidence that they use tools in all kinds of contexts.  You know, tools to get food, tools to attract other mates, you know, tools to kind of sponge off seeds and climb up trees.  Tools for all kinds of different things.  They even seem, in some cases, to have tool kits.  So, kits of tools they’ll use for one particular function, or they’ll use for different part of the same tool and multiple different tools.  And this really impresses us.  But this is kind of the limit of it. You know, there’s nothing like the kinds of complex tools or technologies that we see in humans. 
 
So, one way to classify the difference is that primates actually do seem to use tools, you know, ones that are relatively complicated for other species, but they don’t seem to have technologies in the ways that we do in the sense that they don’t have a sort of cumulative evolution of different tool cultures that in some sense take on a life of their own where multiple individuals are contributing to this.  The kinds of designs that we come up with in one generation get passed on and improved on by the other generation.  Again, you see little bits of this, but nothing at the scale that we have in our own species. 
 
Question:
Why are humans capable of building cumulative technologies while monkeys are not?

 
Laurie Santos: it’s still a big puzzle as to why we’re the only species that has cumulative technology in the way that we do.  One answer that seems to be coming up might have to do with the way that humans imitate other individuals.  So, there was recently a study by Andy White and his colleagues trying to look at the ways that human children imitate a person acting on a tool, versus the way that chimpanzees imitate. 

And so the experiment went like this: Both children and chimpanzees were given a little puzzle box.  It was opaque; they couldn’t see how it worked, but they get to watch a human demonstrator it and open it up.  And the steps to open it up were of two parts.  First it involved a kind of tapping the puzzle box on the top in a certain way, and then it involved opening a door and taking out a treat.  So, both kids and chimpanzees, after seeing this can follow the experimenter perfectly.  So they do the tapping part open the door, get the treat. 
 
Now, you do the same sort of setup, except instead of the box being opaque, it’s now transparent.  And it’s obvious to both the child subjects and the chimpanzees that the whole tapping part of the top is just bogus.  Like the tapping doesn’t actually go anywhere, it’s kind of like a false top.  So you can see as you’re watching the person do this that you don’t need to do this, all you have to do is open the door. 
 
When you give this puzzle to chimpanzees, they do what you might expect to be the smart maneuver; they just kind of cut to the chase and open the door and take the treat.  When you do this with human children, however, what you find, surprisingly—and perhaps embarrassingly for our species—is that the human children slavishly imitate the person they see.  So even though they can clearly see that this, you know, poking on the top is a stupid gesture, they do it anyway. 
 
What it seems like is that humans really are paralyzed by watching the actions of others.  It actually seems to change our causal intuitions about how different objects work.  This is bad when people do really stupid things on boxes and open them the wrong way, but it’s great for the cumulative evolution of technology because it means that you don’t have to know the physics or the causal aspects of how something works, you just basically follow somebody’s actions, do that yourself, and then you can pass on these kinds of cultures to the next generation. 
 
So in some sense, the fact that chimpanzees don’t rely on social information as much as they seem to rely on physics actually means they might not learn about technologies in the same fast way that humans do.  Because if you think about the kinds of technologies that we deal with, you know, they’re often so physically complex that we can’t explain them.  You know, I use my iPhone every day, but I have no idea how it works.  You know, I slide the little bar and that’s what I understand.  But for chimpanzees, all of the technologies they work have physics that are really obvious or affordances that they can see that anyone can see.  Somehow actually paying attention to social information more than physics might have allowed us to go beyond the kind of obvious way that things worked to new kinds of technologies.

Recorded May 21, 2010
Interviewed by Andrew Dermont