To Understand a Monkey, Think Like a Monkey

Scientists had to consider how primates think in order to develop the right experiments to study them.
  • Transcript


Question: Why are Capuchin monkeys such good models for the study of human cognition?
Laurie Santos: So the Capuchins that I study are really distantly related, but they’re actually a great model for human cognition for a couple reasons. One is that being a primate that kind of branched off about 35 million years ago, they actually tell us something about what human evolution, human cognition, probably looked like a really long time ago. So it actually gives us insight not just into our very recent phylogenetic past as studies with chimpanzees might do, but Capuchins actually tell us something about you know, really phylogenetically old similarities that we might share with other primates.
How do primate relationships resemble human relationships?

Laurie Santos: One cool thing about primates is that they, like us, are extremely social creatures.  So, they grow up in a context of social groups, they’re around other kind-specifics—other individuals of the same species—and the social relationships they form really affect their entire lives.  So, it affects what kind of food they’re going to get based on who they hang out with and what rank they are.  High-ranking individuals have easy access to food; where as low ranking individuals may have to wait their turn.  It affects the kinds of mating success they can get, the kind of alliances they form and the way the sort of set up their little social groupings actually can affect just how well they do in terms of natural selection.  So, social groups are really important for most primate species.
Why did it take scientists so long to figure out what primates know about each other's minds? 

Laurie Santos: One of the reasons it took scientists so long to figure out how to ask monkeys about what they know about other minds is that oftentimes researchers were trying to set up studies that might make sense to a human, but probably don’t make sense to a monkey. 
So, one kind of study actually involved a setup where a human was trying to help a primate get a piece of food that was hidden.  So, different pieces of food are hidden, the monkey can’t see where they are, but the human was kind of looking and pointing at one of these pieces of food.  In general, primates did really badly on this, embarrassingly badly. Even with training, they kind of never got it.  But that actually makes sense, like never in the monkey’s life would have ever intentionally cue a human experimenter to where a piece of food was.  This is just a situation which was totally weird. 
So, the insight that we as scientists had was "Let’s use the situations that monkeys are naturally using to deceive us, maybe this is where they will actually show us that they understand something." And now, five or 10 years later, there’s tons of studies suggesting exactly that.

Recorded May 21, 2010
Interviewed by Andrew Dermont