Cold-Induced Amnesia Blocks Escape Deficits in the Cockroach (Periplaneta Americana)

For three consecutive days, four groups of adult cockroaches ( Periplaneta americana) were yoked to cockroaches receiving escapable shock. The four groups of subjects received either inescapable shock followed by exposure to 12 minutes of cold (2° C), inescapable shock followed by no exposure to cold, no-shock followed by exposure to cold, or no-shock followed by no exposure to cold. 24 hr. later all five groups were run on a different escape task. The cockroaches exposed to inescapable shock followed by no exposure to cold showed the usual escape deficit. The cockroaches exposed to inescapable shock followed by exposure to cold did not differ from the escapable shock cockroaches or the controls.

Effects of Shock Controllability on Subsequent Aggressive and Defensive Behaviors in the Cockroach (Periplaneta Americana)

Male cockroaches ( Periplaneta americana) were exposed to either escapable, inescapable, or no shock in an escape task for three consecutive days. 24 hr. later they were placed individually in an aquarium with a naive cockroach and the frequency of aggressive behavior and defensive behavior was recorded by a blind observer. The inescapable shock group of cockroaches displayed less aggressive behavior and a greater tendency to retreat from social encounter than the escapable shock or no shock groups.

Aggression during Learned-Helplessness Pretraining as a Coping Response

This study examined the effects of the opportunity to aggress during pretraining for learned helplessness. While rats individually given inescapable shock showed deficits in subsequent chain-pull escape, the performance of rats given inescapable shock in pairs did not differ from that of animals exposed to escapable shock or no shock. These results are interpreted as contrary to the prediction of the learned-helplessness hypothesis and are consistent with the notion that shock-induced aggression serves an adaptive function.