The Roots of Racism in Rhesus Monkeys

Question: Can monkeys have human-like prejudices?

Laurie Santos: Our newest line of work is actually \r\ntrying to explore whether or not the monkeys share some of the aspects \r\nof human social cognition that we’re not very proud of.  So these are \r\nthings like the fact that we are very, very prejudiced. Even though we \r\ndon’t realize we are, we have these implicit biases against out-group \r\nmembers, against individuals of different religions, different races and\r\n so on. And these biases play themselves out in really insidious ways.  \r\nWe’d really like to know how these biases work, but there are lots of \r\npossibilities on the table for where they come from. Like, you know, we \r\ngrow up in a biased society, there are lots of kinds of cultural \r\ninfluences that are biases.  Are these the real culprits, or is it \r\nsomething a little bit deeper?  Is it something maybe older that might \r\nbe harder to override?
So we actually started studying whether\r\n the monkeys share some of our human-like prejudice against the \r\nout-group. Our first study really just asks this in a really simple way.\r\n We said, "Do monkeys spontaneously distinguish between guys that are in\r\n their in-group and guys that are in the out-group?"  So the experiment \r\nwas super-simple. We did this down at our field site in Puerto Rico, \r\nwhere we study Rhesus monkeys. Monkeys free range around and we sort of \r\nshowed up with this sort of big billboard which had two covers at the \r\nend of it.  When we opened the covers, there were two pictures of \r\ndifferent monkeys.  One guy from their group and one guy from their \r\nout-group. And the really simple measure was, do the monkeys increase \r\ntheir vigilance, kind of get worried about it and stare at more the guy \r\nthat is in the out-group? Again, this is you know, first trial monkeys \r\nthat have ever really seen this weird billboard set up. But we found the\r\n expected result what you might expect from humans, which is that, \r\nspontaneously the monkeys actually direct their vigilance towards the \r\nguy who is in their out-group. The worrying thing seems to be very \r\nsimilar to the way that humans can devote their attention to out-group \r\nmembers. 
And in our next line of studies, we wanted to see, \r\n"Well, are they just kind of looking longer at these guys, or do they \r\nactually treat them differently?"  In other words, do they associate \r\nthem with bad things in their environment?  And there’s a long line of \r\nstudies in people trying to look at whether people do this implicitly.  \r\nThere’s a study known as the "Implicit Association Test" which basically\r\n asks you to do a couple of categorizations. You’re categorizing good \r\nand bad words, and you’re also categorizing in-group and out-group \r\nmembers, you know say, your religion versus a different religion. 
And using this task, researchers have shown that it’s actually very\r\n hard to categorize your in-group with the bad words, and your out-group\r\n with the good words.  You’re actually slower and you make more errors \r\nwhen these categories don’t match up.  Suggesting that even though we \r\ndon’t like to think we do, we have these biases against out-group \r\nmembers that can play out in these really simple contexts. 

\r\nSo we basically did the same categorization measure with our monkeys.  \r\nWe gave them kind of series of different pictures that either matched in\r\n their valance.  So they were all kind of good images to the monkeys, or\r\n they were all bad images to the monkeys.  The idea in those cases was \r\nthe monkey should get bored, kind of good thing, good thing, good thing,\r\n or bad thing, bad thing, bad thing.  Or we set up a list of pictures \r\nwhere the valances differed. And one of these cases was one of pictures \r\nof their in-group members and pictures of bad things in this case scary \r\nspiders.  And what you found was that when the valances were \r\ninconsistent—so in other words, when the in-group members were paired \r\nwith these bad spiders—that actually increased the monkeys' processing \r\ntime suggesting they don’t treat those categories the same way. However,\r\n when you put out-group members with bad things, like spiders, they \r\nactually process them very quickly suggesting that, to a monkey a member\r\n of it’s out-group is basically, in some sense, equivalent emotionally \r\nor in terms of its valance to this scary predator spider creature. 
Same thing when we tried to look at positive images.  So, in-group \r\nmembers, the monkeys seems to process, like fruits really positive, you \r\nknow, good images that they want to approach and come near. But not so \r\nwith out-group members.  So, when you give them pictures of out-group \r\nmembers paired with fruits, it actually takes them a lot of processing \r\ntime.  What it seems like is that spontaneously the monkeys are setting \r\nup the same associations that we humans are, where they are treating \r\nout-group members like negative things and in-group members like \r\npositive things.
Is it difficult to determine which monkeys are "in" and \r\nwhich monkeys are "out" of the group?

Laurie Santos:\r\n For monkeys, in-groups and out-groups are very simple. For humans, it’s\r\n not that simple, right?  We can form groupings based on all kinds of \r\nreally stable social groups like our race, our gender, and so on.  But \r\nwe also form groups on the fly.  You know, we can be Red Sox fans or \r\nYankees fans. You know I can be the gray shirt-wearing person; you could\r\n be a different color shirt-wearing person.  Humans can turn these \r\nthings on really spontaneously. For the monkeys, it depends on how \r\nthey’re born. So the monkeys in this population are born into a \r\nparticular social group.  It’s based on who they’re related to, so they \r\nare born into a particular group, the females stay in that group for \r\ntheir whole lives and the males actually switch groups. 
So, \r\nthe monkeys provide this really cool window because the females live in \r\nthese very stable groups that they’re going to be in for their whole \r\nlives, where the males actually switch.  And so the males actually, you \r\nknow, are in one group for a certain stage of their lives and then \r\nswitch to a new group.  So they kind of, in some sense, have to update \r\ntheir information about what group they’re in, who they like, and who \r\nthey don’t like and so on.
What does the Rhesus monkeys’ behavior tell us about human\r\n groups?

\r\nLaurie Santos:
Our conclusion from this recent line of work suggests\r\n that... first that monkeys actually spontaneously form associations, \r\nform categories of out-groups in the same way that humans do.  So, the \r\nperhaps the exact same thing that humans do when they think about \r\nindividuals from a different race, the monkeys are doing when they are \r\nthinking about individuals from a different social group.  Beyond just \r\nthe fact that they categorize them, they also seem to valance them in \r\nthe same way as humans do. Mainly that they tend to think of the \r\nin-group as a positive entity, maybe actually devote resources more to \r\nthe in-group, and they think of the out-group as a negative entity. 
The thing in humans is that we know that this is true implicitly, \r\noften explicitly people won’t express these prejudices.  But it suggests\r\n that whatever is going on at the implicit level might be a process \r\nthat’s evolutionarily quite old.  And to us that suggests that getting \r\nover these kinds of biases might even be harder than social \r\npsychologists have thought before. 
The monkey work is cool \r\nbecause, what we think it’s telling us is something about the roots of \r\nhuman sexism, human racism, human ageism, basically any form of human \r\ngroup ism—we’re seeing the undercurrents of this in the same cognitive \r\nprocessing we’re studying in the monkeys. 

Recorded May 21, 2010
Interviewed by Andrew Dermont

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