German Chancellor Angela Merkel recently announced that the country's attempts to encourage multicultural harmony, with races living side-by-side, have "utterly failed," and a 2011 BBC headline reads "State multiculturalism has failed, says David Cameron." Others point to race riots in Bradford, Yorkshire, UK and Los Angeles, CA, USA as evidence of the failed policy of multiculturalism.

A recent article in the journal Science (subscription required) refutes this claim. While it's true, the article writes, that humans have evolved a strategy to quickly recognize, stereotype and avoid "outgroup" members, the authors claim another cognitive system exists that allows us to override this stereotype in a way that allows beneficial "coalition building."

"We've evolved to prefer homogeneity, stability, simplicity and structure," says Richard Crisp, psychologist at the University of Kent, UK, "but it can also be adaptive to override this simple fear of outgroups, turning competition into cooperation."

According to Crisp, when you encounter an outgroup member, you have two possible responses -- first, you can depend on the quick categorization of stereotype; or second, your brain can work to override this stereotype and replace it with a new evaluation of this person as a possible ally.

When do we override stereotype? Crisp shows that it's when stereotype proves untrue. Specifically and somewhat counterintuitively, people who have multiple outgroup features -- perhaps an unfamiliar ethnicity, religion, occupation, sexual preference and socioeconomic status -- are more positively evaluated than people with just one outgroup feature. This is because many outgroup features offer a higher chance that some of these features will clash with each other and thus won't fit the stereotype -- like a Caucasian Muslim or a female mechanic -- and so force the equivalent of a cognitive doubletake.

"When we find exceptions to the rule, we have to adjust our heuristics," says Crisp, "and the goal of multicultural policy has to be to force this reevaluation -- to show the incongruence of these multiple outgroup features and so force ingroups to apply this second system of evaluating a person as potential ally as opposed to the first system of simple stereotyping."

Also interestingly, the ability to override your brain's impulsive stereotyping requires cognitive control. And, "Long-term experience at multiculturalism actually improves people's cognitive flexibility," says Crisp. "If you consistently have to inhibit your stereotypes, ultimately the cognitive consequence of living in a diverse society is the release of heuristics in favor of the construction of new knowledge."

As anyone familiar with the famous "marshmallow experiment" knows, the ability to override impulse predicts successes ranging from high SAT scores to a longer marriage. And overruling stereotype trains this useful inhibition. In short, the more you overrule stereotype, the more your train your brain.

Crisp and colleagues have shown this in lab settings when asking subjects to imagine counter-stereotype situations like the female mechanic. In that case, subjects sink into neither "female" nor "mechanic" stereotypes and instead more accurately evaluate the female mechanic based on described, individual characteristics.

"Multiculturalism isn't a failure," says Crisp. "But it depends on forcing humans to think past their stereotypes."

In his opinion, policies that force people to recognize clashes between outgroup features -- like a billboard showing the female mechanic -- still have the potential to put the great experiment of multiculturalism back on the path to success.