AdvertisementCan A Test Really Tell Who's A Psychopath?May 26, 2011Alix SpiegelfacebookEmailAt left, a school portrait of Robert Dixon Jr., on the mantle of his father's home in Stockton, Calif. Though friends and family swear he is a reformed man, Dixon is unlikely to win parole because a test has determined he is a psychopath. (Lianne Milton for NPR)