Influence of shock controllability by dominant rats on subsequent attack and defensive behaviors toward colony intruders

Abstract

Thirty colonies, each consisting of a female and two male adult albino rats, remained intact for an a-week period. Naive conspecific intruders were then introduced into each colony for a 10-min test for 5 consecutive days. Videotapes of the tests were scored for aggressive and defensive behaviors. In every colony, aggression was greatest for a single alpha male. The alpha rats were randomly given one of three treatments: wheel-turn escape training, inescapable yoked shock, or restraint without shock. The alpha rats were then returned to their colonies and an intruder test was given 26 h later. Significant decreases in aggressive responses and increases in defensive behaviors occurred in the alpha yoked group but not in the other alpha groups. The nonalpha colony partners of the alpha yoked rats showed the opposite changes following the treatment. A final intruder test 72 h later revealed that the deficits in aggression of the alpha yoked group were still present but that the behaviors of most of the other groups were beginning to return to their respective pretreatment levels. These findings were discussed in terms of the concept of learned helplessness and alternative theoretical explanations.The finding that prior exposure to inescapable, as opposed to escapable, shock can have dramatic behavioral and physiological consequences has generated much research and theoretical interest (cf. Maier & Seligman, 1976;Sklar & Anisman, 1981). The presentation of inescapable shock has been shown to interfere with the ability of a variety of speciesto later learn a novel response to escape shock (e.g., Anisman, Suissa, & Sklar, 1980;Maier, Albin, & Testa, 1973;Overmier& Seligman, 1967) or to' learn an appetitive operant task (Rosselini, 1978). Transituational deficits resulting from inescapable shock have also been found in tests of nonassociative or unlearned behaviors, such as nonreinforced shuttlebox running (e.g., Maier, Coon, McDaniel, Jackson, & Grau, 1979) and tail flicks to nociceptive stimuli (e.g., that shock-elicited aggression reflects attack or aggressive tendencies has been vehemently challenged on a number of grounds by Blanchard and his col- . First, the specific behaviors typically seen during shock-elictied aggression are very similar to those shown by colony intruder rats under attack and do not resemble the fighting pattern of a dominant male resident in an established colony. Second, the forelimb movements that have typically been interpreted as "striking" during shock-elicited aggression have been shown to partially represent uncontrolled movements elicited by the footshock when the forelimbs are suspended or when the rat is engaged in defensive boxing. Third, the majority of the bites and wounds made by rats during elicited aggression are directed at the conspecific's head region. This target area is far more typical of the defensive behavior of an intruder than the attack fighting of a dominant male in a colony setting.In addition to being a questionable measure of attack behavior, elicited aggressi...

Influence of postpartum shock controllability on subsequent maternal behavior in rats

“…Assuming that such changes in affect are transitional, it is conceivable that inescapable shock might later have a significant influence on how a mother rat interacts with her offspring. This argument is, to some degree, consistent with the fact that differential affective states resulting from shock controllability have been observed in terms of the changes in aggressive and defensive behaviors seen when dominant colony males encounter conspecific intruders (Williams, 1982). However, the major weaknesses of the learned-helplessness interpretation are that (1) it does not specify a precise behavioral or physiological mechanism for why inescapable shock produces a deficit in affect, and (2) it fails to describe the boundary conditions or limits of the helplessness effects.…”

Prolonged exposure to conspecific and predator odors reduces fear reactions to these odors during subsequent prod-shock tests

“…First, it has been known for some time that the development and maintenance of strong social dominance require that rats reside in mixed-sex cages (e.g., Bamett, 1960;Flannelly,Flannelly,& R. J. Blanchard, 1984). Second, the appearance of a high level of aggressive behavior requires that such colonies have repeated agonistic encounters with younger conspecific intruders Blanchard, Takahashi, & Blanchard, 1977;Williams, 1982). Finally, as was observed in Experiment 1, it is not unusual for both of the male residents of an aggressive colony to attack and bite the intruder (Williams & Lierle, 1988).…”

Establishment of dominance in domestic Norway rats: Effects of the degree of captivity and social experience

“…There was also no effect of shock on subsequent agonistic behavior. Flannellyet al (1982) and Williams (1982) found that exposure to shock decreased subsequent aggression in mice and rats, respectively. However, Heller (1979) found increased agonistic behavior in mice that had been exposed to prior shock.…”

“…Sixty-four males, weighing between 400 and 500 g, served as experimental subjects. Males were approximately 130 days of age upon arrival; they were selected at this age because earlier findings had indicated that dominance is not established until about 140 days of age , 1984. Two males, weighing 500-600 g, served as aggressive residents, and 32 males, weighing 350-450 g, were used as intruders.…”

“…A second aspect of the study was the assessment of the role of differential agonistic experience and the effect of exposure to shock on the establishment of dominance in the different environments. Aggressive experience was expected to enhance subsequent offensive behavior, and exposure to defeat or shock was expected to decrease subsequent attack and to increase defensive behavior (Flannelly, Hiraoka, & Flannelly, 1982;Williams, 1982).…”