Human Prejudice Has Ancient Evolutionary Roots
ScienceDaily (Mar. 17, 2011) — The tendency to perceive others as "us versus them" isn't exclusively human but appears to be shared by our primate cousins, a new study led by Yale researchers has found.
In a series of ingenious experiments, Yale researchers led by psychologist Laurie Santos showed that monkeys treat individuals from outside their groups with the same suspicion and dislike as their human cousins tend to treat outsiders, suggesting that the roots of human intergroup conflict may be evolutionarily quite ancient.
The findings are reported in the March issue of the Journal of Personality and Social Psychology.
"One of the more troubling aspects of human nature is that we evaluate people differently depending on whether they're a member of our 'ingroup' or 'outgroup,'" Santos said. "Pretty much every conflict in human history has involved people making distinctions on the basis of who is a member of their own race, religion, social class, and so on. The question we were interested in is: Where do these types of group distinctions come from?"
The answer, she adds, is that such biases have apparently been shaped by 25 million years of evolution and not just by human culture.
Santos and her lab studied the rhesus macaques living on an island off the coast of Puerto Rico. Like humans, monkeys in this population naturally form different social groups on the basis of family history. In order to assess whether monkeys made the same distinctions between ingroup and outgroup individuals, the researchers used a well-known tendency of animals to stare longer at novel or frightening things than at familiar or friendly things. They presented subject monkeys with pictures of monkeys who were either in their social group or members of a different group. They found that monkeys stared longer at pictures of other monkeys who were outside their group, suggesting that monkeys spontaneously detect who is a stranger and who is a group member.
"What made this result even more remarkable" noted Neha Mahajan, a Yale graduate student who headed up this project, "is that monkeys in this population move around from group to group, so some of the monkeys who were 'outgroup' were previously 'ingroup.' And yet, the result holds just as strongly for monkeys who have transferred groups only weeks earlier, suggesting that these monkeys are sensitive to who is currently to be thought of as an insider or an outsider. In other words, although monkeys divide the world into 'us' versus 'them,' they do so in a way that is flexible and is updated in real time."
Santos and colleagues then asked whether monkeys evaluated ingroup and outgroup members differently -- did they associate these individuals automatically with "good" and "bad" respectively? To study this, they developed a monkey version of a test of implicit attitudes known as the IAT. In humans, this test measures the extent to which people show implicit biases against members of other groups. To look at the same capacity in monkeys, the researchers showed monkeys a sequence of photos in which photos of ingroup or outgroup monkey faces were paired with photos of either good things, such as fruits, or bad things, such as spiders.
The researchers then recorded the time monkeys spent looking at both kinds of sequences. The monkeys spent little time looking at sequences that included ingroup faces paired with good stuff like fruits or outgroup faces paired with bad stuff like spiders, suggesting that the monkeys treated these two kinds of stimuli as being similar. On the other hand, the monkeys stared longer at sequences in which outgroup individuals were paired with positive objects like fruit suggesting that this association was unnatural to the monkeys. Like humans, monkeys tend to spontaneously view ingroup members positively and outgroup members negatively.
The Yale team's results suggest that the distinctions humans make between "us" and "them" -- and therefore the roots of human prejudice -- may date back at least 25 million years, when humans and rhesus macaques shared a common ancestor.
"Social psychologists introduced the world to the idea that the immediate situation is hugely powerful in determining behavior, even intergroup feelings," said Mahzarin Banaji, of the Department of Psychology at Harvard University and a co-author of the paper. "Evolutionary theorists have made us aware of our ancestral past. In this work, we weave the two together to show the importance of both of these influences at work."
"The bad news is that the tendency to dislike outgroup members appears to be evolutionarily quite old, and therefore may be less simple to eliminate than we'd like to think," Santos said. "The good news, though, is that even monkeys seem to be flexible about who counts as a group member. If we humans can find ways to harness this evolved flexibility, it might allow us to become an even more tolerant species."
Other Yale authors of the paper are Margaret A. Martinez and Natashya Gutierrez. Researchers from Bar-Ilan University and Harvard also contributed to the study.
The work was funded the National Center for Research Resources, part of the National Institutes of Health.
http://www.sciencedaily.com/releases/2011/03/110317102552.htm
"Experiments are the only means of knowledge at our disposal. The rest is poetry, imagination." Max Planck
- Login to post comments
It's not a new observation, but, it's good that there's an up to date study.
I like the tests. These people are pretty smart
I belong to multiple groups, though. I've got my friends, country, people who think alike (geeks, usually ), etc. If we can get us to believe all humans belong to the same group, the us/them line should get more blurred. Globalisation ftw!
Perhaps you are just being sarcastic and I'm completely misinterpreting you but if you really believe that ( ie, "Globalisation ftw !" ) then be prepared to defend your views against Brian37. To him such talk is almost a sin. He's on another thread (Theist Gunslingers) castigating someone else who makes the same observations as yourself. He appears to me as a zealot who runs from thread to thread accusing people of being the most vile members of humanity if they differ from his "unity" mantra.
That's his opinion ...fine ! ...good ! ...we get it !!! But really, is it necessary to fill almost every post with the same argument over and over and over and over. The endless repetition is mind numbing. He speaks of nothing else. It's like reading a thread started by Paisley......
Yes Brian, It's a great concept, I agree. I believe your motives are honorable, as well. It just doesn't bear up under observation. Reality sucks I guess.
( Ps, I've nothing more to say about it and to avoid further conflict I intend to bypass the sanctimonious ramblings of Brian from now on. Peace through voluntary segregation, as it were.)
I don't always agree with Brian either - well - I always agree with Brian morally, I just don't see things in quite the same idealistic way. I'm too cynical. Nevertheless, as you say, the Brian37 ethos has great merit if only we could get everyone to embrace it.
On the OP I've always thought we should only be allowed to marry those of another race and creed. This would suck the balls of long distance running hyenas for most of us but the progeny of such union would have lost their narky geographical identity and if we could ban sports teams at the same time then group hugs would be assured.
"Experiments are the only means of knowledge at our disposal. The rest is poetry, imagination." Max Planck
But if you force people to marry outsiders, that would kill the total lack of genetic viability in Appalachia.
=
could be made in the interests of social entertainment...
Brian is pretty good with words, and he will most likely kick my ass during our argument, but I'm still going to try. I've got to practice defending my opinion
I was serious, though
None of this is new really or surprising. BUT, you also see even in cute animal pictures of pigs with kittens sucking at their teet, that just as "in group" "out group" is natural in our evolution, so is empathy that helps us solve conflict.
It isn't all bad or all good, but a range. What is interesting in today's age, that does give me some hope that we can be more empathetic and less tribalistic.
Westernized countries for the past 200 years proves that their is a larger effort to shed our tribal past. It is why I can work with my Christian co-workers without wanting to kill them, or them wanting to kill me.
I do think that technology is making it more possible to evolve away from our tribal past, although it will continue to some degree.
"We are a nation of Christians and Muslims, Jews and Hindus -- and nonbelievers."Obama
Check out my poetry here on Rational Responders Like my poetry thread on Facebook under Brian James Rational Poet, @Brianrrs37 on Twitter and my blog at www.brianjamesrationalpoet.blog
You can see this "in group" "out group" behavior in your own pets. If you have one pet, and then introduce another later in years after the one is used to having your attention to itself, it can display anger and jealousy to the new pet.
My moms old dog, who as since died, was nice and happy. When I moved down here I brought my cat. Both the cat and dog were suspicious of each other at first. Time of course cured that.
And you can see this in some dogs in your neighbor's yard to. If the dog doesn't know you, you are seen by it as being part of the "out group" so it will bark at you. BUT, if the owner trains it right it can get over that feeling.
"We are a nation of Christians and Muslims, Jews and Hindus -- and nonbelievers."Obama
Check out my poetry here on Rational Responders Like my poetry thread on Facebook under Brian James Rational Poet, @Brianrrs37 on Twitter and my blog at www.brianjamesrationalpoet.blog