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January 12, 2013

Biased Brains

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  PBS - Race: The Power of Illusion

Race & Ethnicity

Race, Racism and the Law

The Sociology of Race and Ethnicity

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Is it possible to have racial biases without even knowing it? Research on a primitive part of the brain suggests it is. But, as this ScienCentral News video explains, a new experiment shows that simply putting biases into words may help us overcome them.

Unconsciously Biased

"Everyone's a little bit racist," proclaims a muppet-like puppet in the hit Broadway musical Avenue Q — something most of us would probably deny. But, as it turns out, unconscious negative associations with race may be hiding inside our brains.

When we least suspect it, hidden prejudices can pop up. "There is nothing more painful for me at this stage in my life than to walk down the street and hear footsteps and start to think about robbery, and then look around and see it's somebody white and feel relieved. How humiliating," explained civil rights and political activist Reverend Jesse Jackson in an interview in November, 1993.

In recent years, brain researchers discovered that the almond-shaped amygdala, located in the brain's temporal lobes beneath the temples — which have been linked to both fear and pleasure responses and are believed to play a key role in emotions — are associated with a measure of unconscious race bias, especially when a person responds to faces presented subliminally. "White Americans tend to show greater activity in the amygdala when they're looking at African-American faces compared to when they're looking at Caucasian American faces," explains UCLA psychologist Mathew Lieberman."Another thing that the amygdala have been consistently associated with is responding to novel things in the environment, which could be inherently threatening until you figure out what that thing is."

But what Lieberman and his research team have found is African Americans, like Jackson, have similar emotional brain activity to Caucasian Americans when seeing photos of other African Americans. Both ethnic groups viewing African American faces display extremely similar changes in the activity of brain structures that respond to emotional events. "The amygdala is a region of the brain that is known to be associated with responding to threats or emotionally significant events and sometimes more threatening events than positive events," Lieberman says. Changes in the amygdala serve as an alarm to activate a cascade of other biological systems to protect the body from danger.

Using functional MRI (fMRI), the researchers took snapshots of how the volunteers' brains responded differently to looking at pictures of African American and Caucasian American faces. They found that both Caucasian and African American volunteers showed an significantly increased right amygdala response when presented with expressionless photographs of African Americans, than when they were shown pictures of Caucasians. None of the volunteers showed increased activity on seeing pictures of Caucasians. "African Americans, unlike Caucasian Americans, are unlikely to find other African American faces to be novel," says Lieberman. "It may have something more to do with the learned associations." Adding, that from just looking at the amygdala scans it was impossible to tell if the scans were from African Americans or Caucasian volunteers. "[The African Americans] don't show this bias quite as strongly as Caucasia Americans, but it is similar in direction."

However, as the amygdala also responds to unfamiliar things in the environment, the researchers can't be sure if this increased activity actually indicates racial bias. Lieberman cautions against taking such provocative-sounding results too literally, "This is not really full-blown prejudice," he explains. "What we're seeing is something very subtle that may be learned as a function of being a member of this society, where there are negative portrayals of African Americans in the media and in the news and throughout our society," he says. "It's probably not anything that they're consciously aware of doing."

In addition, the researcher studied whether adding a verbal label (such as "African American") when viewing the photos would change the amygdala response. They found that it did.

When the volunteers looked at an African American and said "African American" Lieberman no longer saw the amygdala response. Instead they found changes in a second region of the brain — the right ventrolateral prefrontal cortex — located behind the forehead and eyes, which has been associated with thinking in words about emotional experiences, and with inhibiting behavior, impulses and emotions. When the right ventrolateral prefrontal cortex gets turned on, the amygdala does not. This suggests that the conscious brain may compensate for unconscious prejudices — thinking about the race of others may regulate some of the threat experienced when confronting unfamiliar or feared others.

"Putting our reactions into words in our own minds may be something that allows us to engage in interactions that are more free of bias than they would be otherwise," Lieberman says.

Columbia University Medical Center neuroscientist Joy Hirsch, who also conducts brain-scanning experiments, says that the study is just a first step. "It's a really important milestone in neuroscience when we can address questions as important as attitudes, judgments, complex behavior, using neuro-scientific methods, and neuro-imaging," she says. "But when we do, we're left with additional questions." She adds that racial bias may be too complex — and personal — for neuroscience to fully explain.

Lieberman and Hirsch agree that future studies may test the amygdala's response to other ethnicities, animals or even inanimate objects.

Lieberman's research was published in the May 8 online version of Nature Neuroscience, and was funded by the National Science Foundation and the National Institute of Mental Health.

       email to a friend by Lindsay Carswell

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