A longstanding line of research that aims to combat bias among conflicting groups springs from a theory called the "contact hypothesis." Developed in the 1950s by Gordon Allport, PhD, the theory holds that contact between two groups can promote tolerance and acceptance, but only under certain conditions, such as equal status among groups and common goals. Since the theory's inception, psychologists have added more and more criteria to what is required of groups in order for "contact" to work.

Recently, however, University of California, Santa Cruz research psychologist Thomas Pettigrew, PhD, has turned this research finding on its head. In a new meta-analysis of 500 studies, he finds that all that's needed for greater understanding between groups is contact, period, in all but the most hostile and threatening conditions. There is, however, a larger positive effect if some of the extra conditions are met.

His analysis turned up another unexpected finding that also runs counter to the direction of the field. The reason contact works, his analysis finds, is not purely or even mostly cognitive, but emotional.

"Your stereotypes about the other group don't necessarily change," Pettigrew explains, "but you grow to like them anyway."

Pettigrew is currently submitting his study for review; the basic findings can also be found in a chapter by him and Linda Tropp, PhD, in the book "Reducing Prejudice and Discrimination" (Erlbaum, 2000).