SAN FRANCISCO - Shiite vs. Sunni. Red state vs. Blue state. Immigrant vs. native.
While it may appear that conflict is an inevitable part of interaction between groups, research actually suggests that fighting, hating and contempt between groups is not a necessary part of human nature, according to an Ohio State University professor of psychology.
"There's still this belief that a group's cohesion depends on conflict with other groups, but the evidence doesn't support that," said Marilynn Brewer of Ohio State .
"Despite evidence to the contrary, you still see this theory in the research literature and in many textbooks."
Brewer has spent much of her career studying "ingroups" - the groups we belong to - and their relations with "outgroups" - those groups to which others belong.
She discussed the nature of these intergroup relations in her invited address Saturday Aug. 18 in San Francisco at the annual meeting of the American Psychological Association. The address was in honor of Brewer winning the 2007 Distinguished Scientific Contribution Award from the APA.
In her address, Brewer said recent evidence suggests that people's attachment to their ingroups has nothing to do with conflict - or indeed any other kind of relation - to other groups.
Instead, people join groups to find a place of trust and security.
"Simply put, we prefer people of our kind, people we know we can rely on. That doesn't mean you have to hate anyone else. But you will be more likely to trust people from your own group," Brewer said.
In one recent study, for example, Brewer found that people tended to put more trust in total strangers when they learned this stranger attended the same university they did.
"All you need is to have that shared group identity," she said.
The evolutionary history of humans suggests there is no need to require intergroup conflict to account for the formation of ingroups. Early humans didn't live under dense population conditions in which groups had to compete for local resources.
Given the costs of fighting, and the lack of need to compete, groups would have been more likely to flee from each other rather than fight.
That doesn't mean ingroup bias is benign, Brewer said. Ingroup bias is the basis for discrimination, the favoring of people in your group over those in another.
"You don't have to hate people from other groups in order to disadvantage them and to deny them the opportunities you have in your group," she said. "That's a real downside to ingroup bias."
Another common misconception about the formation of groups is that people join to boost their self-esteem. In other words, the argument is that the purpose of joining groups is to say "my group is better than your group." Again, research disproves this theory, Brewer said.
"The basic underlying mechanism for ingroup favoritism is trust and security and not self-esteem," she said.
Research has shown that when people are asked why their ingroup is better than other groups, they focus on traits such as trustworthiness, friendliness and kindness.
People don't necessarily say their group is wealthier or smarter or more successful than others.
"Most people are reality bound. They know if their group is not as good as others when it comes to things like wealth, and they won't pretend otherwise," Brewer said.
"If people were just looking for self-enhancement, they would just say their group is the best at everything, and that isn't the case. What people are really looking for is trust and security."
While conflict and hate don't need to be a part of group membership, a look at the news today shows that conflict does occur often, when groups battle over resources, or threats to identity or values.
When people are secure about their own identity and the identity of their group, and there is no competition for resources, conflict is not normally a problem. But if people are insecure about what their group means, or their place in it, they may support conflict as a way to enhance cohesion within the group, Brewer said.
That suggests that marginal members of a group - those who feel least included - will be the ones most concerned about keeping distance between groups and pushing hostility toward outgroups.
One way to minimize conflict between groups may be to take advantage of the fact that people belong to many groups with cross-cutting memberships, Brewer said. People have their national and racial identities, occupational and religious groups, school or alumni groups, as well as neighborhood, hobby and club affiliations.
"People have these different group identities and we've been working on ways to find out how people understand these memberships and how it affects their attitudes toward other groups," she said.
"We do find that those people who have multiple identities and experience these identities in complex, cross-cutting ways, are indeed more accepting of diversity and have more positive feelings toward racial and religious outgroups. That suggests that there are psychological ways of breaking the boundaries of our small ingroup-outgroup distinctions."