The racial attitudes of white college students from the mainland shift after nine months on the islands.

(Photo: MIKE Nelson/AFP/Getty Images)

It is harder to hold onto racial prejudices—either subtle or overt—when your social circle features people of various ethnicities. This dynamic has been demonstrated in several studies featuring children, but whether such interaction truly affects adults over time is difficult to test.

New research does just that, taking advantage of the existence of a multicultural American environment: Hawaii. A group of young white adults demonstrated a decline in racist beliefs and enhanced cognitive flexibility after living in the state for nine months.

These promising findings, reported by a team led by psychologist Kristin Pauker of the University of Hawaii–Manoa, are published in the journal Social Psychological and Personality Science.

The study featured 99 white first-year students at the aforementioned university, all of whom moved to Hawaii from the continental United States to attend college. They filled out a detailed questionnaire when they initially arrived on campus, and again nine months later, at the end of their first school year.

In it, they noted how many of their friends, close friends, and acquaintances identified as Asian, black, Hispanic, white, and biracial. They also completed surveys designed to identify racist assumptions, and the belief that race is biologically based as opposed to socially constructed.

A nine-month sabbatical in Hawaii could effectively open hearts and minds. Any takers?

Finally, they took a test measuring cognitive flexibility—roughly speaking, the ability to think outside the box. They were given a series of categories (such as "vehicle") and then asked how well three terms ("car," "bike," and "camel") fit into them. Those who could envision a camel being used as a vehicle, and make similar mental stretches, were considered more cognitively flexible.

The key result: Over the course of the school year, the students significantly reduced their belief in "racial essentialism"—the view that racial groups possess underlying essences that represent deep-rooted, unalterable traits.

Furthermore, "for white students whose racial essentialism decreased, there was an increase in their egalitarian attitudes and cognitive flexibility," the researchers report. Becoming more open-minded about people apparently inspires more open-mindedness in general.

"It is unlikely that this effect was (simply) because of attending college," the researchers write, "as students from Hawaii, who did not experience a shift in the diversity of their environment, did not exhibit a decrease in racial essentialism."

Rather, the new experience of getting to know a diverse group of people—even if they don't become personal friends—seems to drive this reduction in bias.

Given these results, it's worth recalling that Donald Trump received his greatest support in virtually all-white regions of the country. (He received only 30 percent of the vote in Hawaii.) This research indicates such divisive appeals may grow less powerful if and when racial diversity spreads to more of the nation.

In the meantime, the results suggest a nine-month sabbatical in Hawaii could effectively open hearts and minds. Any takers?