Biased Brains-Do They Exist?

Wednesday June 29, 2005

Forty years after the American Civil Rights movement, studies show that many people still harbor unconscious racial biases.

ScienCentral News reports advances in brain imaging are shedding light on how and where these biases express themselves.

Accusations of racial bias can surround tragedies like 1999's New York Police shooting of unarmed black immigrant Amadou Diallo, but while neuroscientists like Matthew Lieberman know that such biases are often unconscious, where they come from remains a mystery.

He suspects the answer involves a primitive area of the brain called the amygdala, "So the amygdala is a region of the brain that's been associated with responding to threats or emotionally significant events." 

Lieberman used an MRI scanner like this to take snapshots of people's brains as they viewed photos of African-American faces. Caucasian participants showed an increased amygdala response, indicated here in yellow, when they looked at the pictures. But so did the African-American participants. "They don't show this bias quite as strongly as Caucasian-Americans do, but it is similar in direction," he says.

Lieberman's findings, published in the journal Nature Neuroscience, suggest that brain scans may reveal evidence of unconscious racial bias. But he doesn't believe that means people are born prejudiced. "I think what we're seeing is something that's very subtle that may be something that's learned as a function of being a member of this society," Liberman says.

Columbia University Neuroscientist Joy Hirsch agrees. "There's never any one study, or one approach, that will answer questions about behavior as complex as biases," Hirsch says.

Even so, Lieberman does believe that studies like these may help us identify and overcome unconscious biases. Future studies may test the amygdala's response to pictures of other races, animals, or even inanimate objects.

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