Ask any humanitarian volunteer you’ve walked past on a sidewalk — it's an incredibly difficult job to get people to commit themselves to a cause or relief effort in another part of the world. The way we receive information about suffering is a key factor. A University of Bradford study shows consuming an overwhelming amount of violent imagery can desensitize people by shutting down the part of the brain that activates empathy in order to protect itself. As the number of victims increases, empathy can plateau or even go down, a phenomenon the Arithmetic of Compassion project calls psychic numbing. As psychologist Paul Slovic explains it, our brain is better able to process information and develop complex impressions about one person suffering than it can for larger numbers. And although we’re capable of feeling empathy for anyone, behavioral research shows increased neural responses to the perceived pain of individuals of the same race.