Researchers have found that psychopaths’ brains may be wired to more aggressively seek out rewards, explaining their quest for sex, money, and fame at any cost. Subjects in a Vanderbilt study who had more psychopathic traits were found to be more likely to have higher levels of dopamine and more activity in the part of the brain dedicated to seeking—and getting pleasure—from rewards. The people who participated in the study weren’t criminals. "The people in our study might be your Machiavellian mother-in-law, your bullying boss and your conniving coworker, but none of these people were out there committing violent crimes," a researcher told NPR. "Crime is extremely expensive… and psychopaths commit more crime than anybody else,” which is why more studies of antisocial behavior are important, he said.