Early explanations for factors deviance identified supernatural causes or genetic factors (such as “bad blood” or evolutionary throwbacks to primitive ancestors). By the 1800s, there were substantial research efforts to identify biological factors that lead to deviance and especially to criminal activity. While such research has been discredited in the twentieth century, contemporary studies, primarily by biochemists, have sought to isolate genetic factors leading to a likelihood of certain personality traits. Although criminality (much less deviance) is hardly a personality characteristic, researchers have focused on traits that might lead to crime , such as aggression. Of course, aggression can also lead to success in the corporate world, professional sports, or other areas of life.