Today, Americans profess unprecedented levels of tolerance toward interracial couples when asked about them in surveys.
But a new study suggests that the responses to such surveys aren't always entirely true.
University of Washington researchers Allison Skinner and Caitlin Hudac set up a series of experiments to test the brain activity of college students when presented with interracial couples.
In one experiment, the researchers hooked 163 undergraduate students up to brain activity monitors, then showed them wedding and engagement photos of 200 interracial and same-race couples. The subjects asked to indicate whether each couple was worthy of being included in a future study on relationships—meaning, whether they found each couple generally acceptable.
The results showed significantly more brain activity in an area of the insula, a part of the cerebral cortex that is associated with feelings of disgust, when the subjects viewed images of interracial couples than while viewing images of same-race couples (both black and white).
You can see the results here: for interracial couples (at the top), the responses are bright red with "strong activation," while for same-race couples the response is darker red with "weak activation."
"Our findings suggest that people are disgusted by interracial romance and that translates into a heightened disgust response when faced with interracial couples," they write.
In another, the researchers set up a game where subjects were asked to hit a button when same-race couples were matched with silhouetted couples of humans and when interracial couples were matched with animals, and vice-versa. They found that the subjects were more quick to hit the button when interracial couples were matched with animals than when they were associated with humans.
"There was a general tendency to implicitly dehumanize interracial couples relative to same-race couples," the researchers wrote.
In a survey given at the start of the experiments, most of the students indicated they were accepting of interracial dating. Yet, fewer than 10% of them (out of 152 college students surveyed, 87% of whom were white) said they had dated or lived with a person of another race themselves, and more than a third said they would not date, marry or have a child with person of another race even though they thought it was okay if someone else did it.
The researchers concluded that, despite growing acceptance of interracial couples in the U.S., there may still be considerable implicit bias against them. In a phone interview, Skinner said these sentiments are not likely hardwired, but rather conditioned by society.
"We truly do believe ourselves to be non-biased, but given right circumstances, it’ll come out," she said.
Rob covers business, economics and the environment for Fusion. He previously worked at Business Insider. He grew up in Chicago.