College students showed signs of disgust when they saw photos of interracial couples. (Photo by iStock)

Most people in the United States say they accept interracial relationships, but a new study of brain activity shows some hidden bias.

Researchers surveyed students at the University of Nebraska — young people, not those who grew up in a more overtly racist time — and recorded their brain activity while they looked at pictures of hundreds of couples.

In a survey of attitudes about relationships, the students reported little disapproval of interracial couples. But photos of interracial couples triggered activity in a part of the brain that registers disgust.

“It shows that people show some level of disgust based on the [national] polls saying that everything is fine,” said Allison Skinner, lead author and postdoctoral researcher at the University of Washington, who published the study in the Journal of Experimental Social Psychology.

Skinner said the students at the Midwestern university may not be representative of the entire nation, but she added that their feelings are “probably not exclusively a Nebraska thing.”

About 1 in 8 people who married in 2013 tied the knot with someone of a different race, according to a Pew analysis of American Community Survey data. That’s about 12 percent, nearly double the share in 1980 when it was 6.7 percent.

The study comes as the new movie “Loving” is set to debut in theaters in November. The film chronicles the story of Virginia couple Mildred and Richard Loving, whose illegal mixed-race marriage led to the landmark decision by the U.S. Supreme Court in 1967 to legalize interracial marriages nationwide.

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Researchers conducted three experiments from 2013 to 2015, studying the views of college students at the University of Nebraska on heterosexual couples in which one person was black and the other white.

“We chose to limit our investigation to black-white interracial romances because previous research indicates that whites show the strongest opposition to black-white interracial couples,” according to the study. “We chose to avoid adding an additional layer of complexity by restricting our investigation to heterosexual couples.”

In the first experiment, 152 students were asked whether they accepted mixed-race relationships. The respondents were about evenly split between the sexes; 87 percent were white, 5 percent were Latino, 3 percent were Asian, 3 percent black and 2 percent were of some other race.

As part of a longer survey, participants were also asked to rate on a scale of 1 to 100 how disgusted they felt about a black man in a romantic relationship with a white woman, or a white man in a relationship with a black woman. Participants were also asked whether they would date, marry or have a child with a black person. Acceptance was high overall for both sets of relationships, but for those who disapproved, “the less accepting you are of interracial relationships, the more disgusted you are by them,” Skinner said.

In the second study, 19 participants had their brain activity monitored by electroencephalogram (EEG). They were shown 200 real engagement and wedding photos: 50 black men with white women, 50 white men with black women and 50 each of same-race black and white couples.

While sitting in front of a computer, the photos of mixed-race and same-race couples were randomly shown to participants. They were told that they had to quickly respond to whether the couple should be “included” or “excluded” from a future study on relationships by pressing a button that corresponded to each answer.

Researchers found that the insula, a part of the brain that registers disgust, was highly active when participants viewed the photos of the interracial couples, but was not highly engaged when viewers saw the images of same-race couples, whether they were white or black.

“There’s a significant difference between the activation of the insula between interracial and same-race couples,” Skinner said. “The way we have been interpreting that is that people are experiencing a heightened level of disgust when they are socially evaluating or viewing interracial couples relative to same-race couples.”

Researchers said there is a link between disgust and dehumanization, and therefore they sought in the third experiment to determine whether disgust “leads to dehumanization of interracial couples.”

They studied 226 students, some of whom were shown 10 disgusting images, such as a dirty toilet or people vomiting. A control group viewed images of landscapes of nature and cities.

Viewers were then shown images of same-race couples, mixed couples and silhouettes of animals and humans and asked to press a button as quickly as possible to indicate which images showed animals or humans. The study participants were faster to identify same-race couples as humans.

But one of the bigger take-aways of that experiment was that when people were already made to feel disgusted by the gross images, they were more likely to elicit a strong reaction against interracial couples. It’s a warning, Skinner said, that this country has not gotten rid of its bias against interracial romance.

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