Researchers have studied the part of the brain associated with disgust to reveal people’s true attitudes.
Next year marks the 50th anniversary of the US Supreme Court decision ruling bans on interracial marriage unconstitutional.
While the ruling in Loving v. Virginia (1967) was controversial at the time – in 1958 just 4% of Americans approved of marriages “between white and colored people” – today polls indicate that most Americans (87%) accept interracial marriage.
Yet incidents of overt prejudice – even violence – against interracial couples keep cropping up. In April, a Mississippi landlord evicted a family after he found out the couple was interracial. Then, this past summer, a man stabbed an interracial couple after seeing them kiss in public.
As a social psychologist, I’ve often wondered: are these types of incidents aberrations? Or are they indicative of a persistent, underlying bias against interracial couples – something not captured by self-reported polls?
To test this, my colleague Caitlin Hudac and I designed a series of studies to examine how people really feel about interracial relationships.
Insights from the insula
Through the early 20th century, many Americans reacted to the idea of interracial marriage with revulsion. For example, Abigail Adams reportedly said that “disgust and horror” filled her mind when she saw dark-skinned Othello touch pale-skinned Desdemona in the theatrical production of Othello.
Yet even though attitudes have supposedly changed, contemporary commentary on interracial marriage will still refer to a “gag reflex” that some people continue to feel – as The Washington Post’s Richard Cohen noted a few years ago.
This feeling – disgust – is the one we decided to zero in on.
First we asked a predominately white sample of college students to report how disgusted they feel by interracial relationships between blacks and whites. We also had the participants tell us how accepting they were of interracial relationships between blacks and whites.
Consistent with polling data, we found that participants claimed to be largely accepting of interracial relationships. We also found that disgust and acceptance were highly correlated; the less accepting people were of interracial relationships, the more disgusted they were by them.
The problem with asking people to report on their own attitudes about sensitive topics like race and gender, however, is that people are often either unaware of their own biases or unwilling to report them. For example, although most white Americans self-report little to no racial bias against black people, they’ve been shown to possess robust implicit, or nonconscious, biases.
To get around this problem, we conducted a second study in which we measured participants’ brain activity – not their own reports. Using an electroencephalogram (EEG), which measures electrical activity in the brain, we recorded the brain waves of a predominately white sample of college students while they viewed 100 images of black-white interracial couples and an equal number of same-race couples (black and white).
We wanted to see what would happen in an area of the brain known as the insula, which has been shown to become activated when people feel disgust. In other words, would the insula of participants light up when viewing interracial couples?
We found exactly that: overall, participants showed a heightened level of activation in the insula when looking at interracial couples relative to looking at same-race couples.
Although the insula is not exclusively linked to disgust, taken with the results of our first study these findings suggest that people do tend to be more likely to experience disgust when viewing interracial couples.
When we’re disgusted, what happens next?
In our final study we wanted to look at the ramifications of feeling disgusted by interracial couples.
There’s a fair amount of psychological research showing that feeling disgusted by others often leads us to dehumanise them. So we wondered whether the disgust people experience in response to interracial couples might lead them to dehumanise them.
To test this, we recruited another predominately white sample of college students and divided them into two groups. One group was shown a series of disgusting images (e.g., people vomiting, dirty toilets) and the other group was shown a series of pleasant images (e.g., scenery, city skylines). This was done to induce some participants to experience disgust – which was expected to make them more likely to dehumanise people.
Next, we had participants complete an implicit association test (IAT). During IATs, participants need to make split-second categorisations of concepts and categories; because there’s almost no time to reason or think, it tests our nonconscious associations.
For our study, we had participants quickly categorise images of interracial couples, same-race couples, silhouettes of humans and silhouettes of animals. The silhouettes were there to represent “humanisation” and “dehumanisation,” respectively.
In one part of the task, participants were told to use one button to categorise images of interracial couples and silhouettes of animals; they were told to push a different button to categorise images of same-race couples and silhouettes of humans.
Next these pairings were switched: we had participants push one button if they viewed images of same-race couples and silhouettes of animals. The other button was used to categorise images of interracial couples and silhouettes of humans. We predicted that participants who were primed to be disgusted (those who viewed the disgusting images in the beginning of the study) would do the task faster when they’d been told to categorise interracial couples and animals with the same key.
What we found is that all participants were able to complete the task quicker when interracial couples and animals were categorised using the same button (which is indicative of implicit dehumanisation). However, participants who had been primed to be disgusted were able to do it the fastest.
The slippery slope of dehumanisation
Overall, this research suggests that, when it comes to attitudes about interracial relationships, polls don’t tell the whole story. Interracial couples still elicit disgust in many people; this disgust can translate into dehumanisation of interracial couples.
However, these results do not mean that it’s natural to feel disgust about interracial relationships; we are not born with these biases. Rather, the existence of these biases is evidence of deeply ingrained societal attitudes about race in our culture – and there is a new and growing field of research on methods to reduce these biases.
Still, the findings are particularly striking given that all data was collected from college students – and polls show that millennials, of all age groups, say they are most accepting of interracial relationships.
Although our research cannot speak directly to the consequences of dehumanising interracial couples, the implications are startling. When we dehumanize people it frees us from the burden of empathizing with them or having compassion for their struggles. And at its most extreme, dehumanisation can lead to acts of violence and cruelty – like the stabbing from earlier this summer.
Allison Skinner is a psychology researcher at the University of Washington.