"There's really no such thing as race," world-famous scientist, author, and television personality Bill Nye told Big Think in 2015. "There's different tribes but not different races. We're all one species."

Despite the fact that there's no scientific basis for the idea of racial differences - a point hammered home by the sequencing of the first human genome, or complete set of DNA, in 2003 - we continue to see ourselves as distinct along racial lines. And these perceptions have real consequences, both in terms of individual behaviour and institutional policies.

Scientific research suggests that the vast majority of us are highly aware - consciously or subconsciously - of racial differences and, whether we want it to or not, this knowledge plays a key role in empathy.

In their 2009 paper in The Journal of Neuroscience, researchers at Peking University did an experiment in which they showed white and Chinese students clips of white and Chinese faces both in pain and not in pain while they measured their brain activity using functional magnetic resonance imaging (fMRI).

The researchers were paying particular attention to brain activity in an area of the brain called the anterior cingulate cortex (ACC), which scientists think plays a key role in registering our own pain and empathy for another person's pain.

For all of the participants, ACC activity was significantly higher while they were viewing painful expressions on the face of someone of their own race, and lower when they viewed pain on the face of another race. The results were in accordance with the hypothesis the researchers started with - that social relationships between individuals influence empathic responses, where an individual experiences higher empathic responses for those in the same perceived social category.

For a 2010 study published in the journal Current Biology, researchers at the Department of Psychology at the University of Bologna conducted a two-part test on groups of white Italians and black Italians.

For the first part of the test, they asked the volunteers to match 'good' and 'bad' words with images of black and white faces. For the second part, they showed the participants images of a black, white, and purple hand being pricked with a needle while they tested neural response to the pain using by stimulating the motor cortex of the brain. The higher the empathic response, the greater the reaction to the stimulation.

Interestingly, while both white and black volunteers showed adequate reaction to the stimulation while they watched the purple hand being pricked, neither groups showed as much activity when they watched a hand of someone outside their racial group being pricked.

Additionally, those who tended to match more 'good' words with images of people from their own racial group and more 'bad' words with another racial group (which suggested what the researchers called implicit racial bias) had even lower neural response while watching a hand of the opposite race being pricked.

No one wants to believe that he or she is racist. However, there is enough conclusive evidence to suggest that the vast majority of us are either consciously or sub-consciously less empathetic toward people of other races.

While it is hard to control subliminal responses, a conscious effort to act without bias could be a way to combat the surreptitious racism. Or maybe increased interactions with different 'races' could help our brains see that we are 99.9 percent the same.

This article was originally published by Business Insider.

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