Reinforcement of Intra- and Inter-Species Aggression with Intracranial Stimulation

Intracranial stimulation was used as a reinforcer to condition fighting in paired rats. Stimulation for an implanted animal was made contingent upon responses which successively approximated those typical of attack. A stable pattern of aggression developed, the maintenance of which was possible on intermittent reinforcement schedules although at depressed frequencies. An implanted rat also readily initiated contact with a cat and made consistent, aggressive approaches toward a squirrel monkey. The aggression observed appeared to be a function of operant reinforcement since extinction occurred when the intracranial stimulation contingency was removed.