It’s hard to imagine why a person would perform such a cruel act on an innocent animal, even if it were already dead. Yet psychologists see it all the time, most commonly in the form of antisocial personality disorder (frequently termed “sociopathy”), which is characterized by extreme disregard for the safety of others.

Herbert Nieburg, a Connecticut-based clinical psychologist and consultant for the Federal Bureau of Investigation (FBI), said patients with this disorder often pursue “wanton thrill-seeking” and get a pleasurable feeling of power from hurting a more vulnerable creature.