Abstract: | This experiment demonstrated that rats trained to display elevated levels of shock-induced aggression in a negative reinforcement paradigm displayed more boxing behavior than yoked control groups in a later test in which intruder rats were placed in the home cage of resident rats. Resident or intruder status did not affect the influence of the negative reinforcement procedure on the observed resident-intruder behavior of trained animals; however, naive intruders paired with trained residents displayed increased defensive behavior, suggesting that negative reinforcement for shock-induced aggression affected the behavior of these residents. |