Racial biases sometimes come straight from the heart, study finds
Researchers say stereotypes have become ‘embedded in our physiology’
Studies have shown that when some people see pictures of black individuals, implicit racial biases can make them more likely to perceive a threat that’s not there — like mistaking a cellphone for a gun.
Now, researchers are investigating what happens inside the body when our brains make errors based on racial stereotypes.
Published Tuesday in Nature Communications, a new study found that racial biases were enhanced in white and Asian volunteers when they saw images of a black person during their heartbeat, as opposed to between beats.
The team of British researchers explained that this is because signals sent from the heart can provoke a threat response in people with implicit racial biases, causing them to make erroneous snap judgments about whether a black person is holding a cellphone or a hand- gun — a finding that may offer insight into police shootings of unarmed black people in the United States.
“Racial stereotypes seem to be embedded in our culture,” said senior author Manos Tsakiris, a psychology professor with Royal Holloway University of London. “What we’re showing with this particular study is that they have also become embedded in our physiology.”
Police targeting of black people is an explosive and ongoing issue in North America. In the U.S., multiple fatal encounters involving police and black men have been captured on video in recent years.
Black Americans are three times more likely than white Americans to be killed by police, according to the research collaborative Mapping Police Violence. A 2015 study published by PLOS One also found that in the U.S., black people are more than twice as likely to be unarmed when killed during a police encounter compared to white people.
These grim statistics motivated Tsakiris and his team to tackle their latest study, which builds on previous work investigating how bodily processes influence the way people perceive the world.
Co-author Sarah Garfinkel, a research fellow in psychiatry with Brighton and Sussex Medical School, has focused her work on the connection between the heart and brain, which are constantly in communication.
With every heartbeat, a blast of data gets sent to the brain — information about heart rate, blood pressure or state of arousal, for example. Between heartbeats, however, this channel goes quiet. No signals are fired.
Garfinkel’s past studies have shown that when people are given a “fear” stimulus timed with their heartbeat — for example, a photo of a scared facial expression — a stronger fear signal is activated in their amygdala. This is the brain region involved in “fight or flight” responses.
“People will judge this fear stimulus as more threatening,” she explains.
But when shown the same picture between heartbeats, when the heart isn’t firing signals? That fear reaction is dampened.
Garfinkel and her colleagues wanted to investigate whether this same process applies to racial biases, too. Could signals from the heart trigger fearful reactions based on racist stereotypes?
To test this, they performed a series of experiments, each involving about 30 people (small sample sizes are common in social psychology, where studies are limited by the nature of the experiments).
In the first, they asked people to identify pictures of handguns or tools, like wrenches and pliers. Each image was preceded by a flashing picture of a white or black person, timed to appear when their heart was either beating or between beats.
When people saw a black person during their heartbeat, they were more likely to misidentify a tool as a gun.
In fact, they made about 20 per cent more errors compared to when they were flashed a white person’s face during their heartbeat.
“They are statistically significant results,” Tsakiris said. “These are pretty large effects.” When shown the faces between heartbeats, however, this margin of error vanished — study volunteers were equally accurate at identifying tools, regardless of whether they were shown a picture of a black or white person.
The same pattern emerged when participants were asked to perform a “first-person shooter task.” In this experiment, study volunteers were shown photos of a white or black person, holding either a cellphone or handgun. They were then told to quickly press a computer key and “shoot” individuals with a gun in their hand.
When the images were flashed during their heartbeat, volunteers were about10 per cent more likely to shoot an unarmed black person compared to an unarmed white person — a discrepancy that again largely disappeared when the images were flashed between heartbeats. So what does this mean? “The propensity to actually misperceive tools or mobile phones for guns — specifically when these are held by black individuals — is critically dependent on the information that comes from the heart to the brain,” Tsakiris said. He explains when people are looking at these images, two brain processes are playing out simultaneously.
One is automatic; signals from the heart to the amygdala, the brain’s fear centre. The other unfolds in the pre-frontal cortex, where more rational decisions are made.
The second process is meant to reg- ulate the first. But for people with racial biases, the flashing face of a black person presented during a heartbeat — when signals are sent to the brain — causes the brain’s emotional, fear-based response to override more sophisticated cognitive processes.
The brain thinks: “I’m frightened. I have a reason to be frightened . . . what’s the best explanation for this ambiguous object in front of me? If I’m frightened, it must be a gun,” said Karl Friston, a prominent theoretical neuroscientist and brain imaging expert with the Wellcome Trust Centre for Neuroimaging, who wasn’t involved with the study.
All of this rapid-fire processing occurs in a split second, before someone can become aware of what’s happening, Friston notes. “It tells you how easy it is for these prior prejudices to get in and cause you to misperceive.”
This new study is part of an emerging body of research that is shifting how we understand the human brain — not as a reactive organ, but a predictive one.
“A majority of your brain activity consists of predictions about the world — thousands of them at a time — based on your past experience,” psychology professor Lisa Feldman Barrett wrote in a 2015 article for the New York Times.
“If you’re in a produce section, your brain is already predicting that an apple is nearby. If you are in a part of town with a high crime rate, your brain may well predict a weapon.”
If our brains make predictions based on past information, then cultural representations of race become critically important in shaping how brains automatically respond.
Tsakiris points to one example from last June, when a Twitter user posted a video of himself performing a Google image search for “three white teenagers.”
The results were photos of happy, smiling teens, mostly playing sports. When he did the same search for “three black teenagers,” the results were mostly mug shots.
“These are culturally formed associations but eventually, they become embedded in our brain processes,” he said.
“The danger is, in fact, that these kinds of associations become automatic. They become embodied.”
Tsakiris would like to now repeat his study with police officers and see whether they show similar results when flashed with the same images during their heartbeats (he suspects they will).
He hopes his research can help address the problem of biased policing — perhaps by developing tests to identify officers who are susceptible to racial biases or developing interventions that can help their brains “unlearn” these implicit racially biased associations.
He concedes, however, that truly addressing the problem of biased police shootings will require broader, societal change.
“We live in a culture, especially in the U.S., where negative stereotypes, associations and prejudices about black individuals are pretty well established for all the wrong reasons,” Tsakiris said.
“Race is such a complex issue that it won’t dissolve in a psychology lab.”