[Is pain-induced aggression actually a defensive form of that behavior?]

25-minute testing of aggressive reactions in constant pairs of male rats, elicited by electric shocks shows that electro-pain aggression of rats is not a homogeneous process, but consists of three successive stages: orienting-investigatory activity and attempts to get out of the chamber; defensive aggression; establishing of relations of domination-subordination and attacking aggression. Division in attacking rats and defending themselves, occurs mainly at final stages of testing (15-25 min); in some pairs reactions of attacking aggression are accomplished by the same rats. It is supposed that rats pain aggression is not a purely defensive form of this behaviour, but a modification of intermale aggression caused by specificity of laboratory conditions.