Two experiments investigated the relationship between activity during shock and the magnitude of subsequent impairment of shock-elicited fighting in the rat. Different levels of intrashock activity were engendered in two ways. In Experiment I, differing temporal forms of inescapable shock were employed to produce markedly different levels of activity. In Experiment 2, a passive-escape procedure was used to explicitly reinforce nonmovement during shock relative to a yoked, inescapable shock control. Results indicated that relative to the performance of subjects not previously shocked, fighting impairment was produced only by those prior treatments that promoted reduced intrashock activity. Since one of the prior shock treatments involved inescapable shock but the other did not, these findings may be viewed as strong support for the notion that behavior during shock, rather than uncontrollability, is the critical determinant of the observed impairment effects. There was some suggestion in both studies that shock treatments that resulted in sustained or increased intrashock activity tended to produce augmentation of fighting. Both inhibitory and facilitative effects of prior shock exposure are discussed in terms of an interacting response theory of shock treatment effects.Recently, support has been provided for the view that levels of activity exhibited by rats during inescapable shock may be a determinant of the magnitude of subsequent impairment with escape-avoidance learning produced by such experience. Much of this evidence stems from experiments that attempted manipulations of activity levels during inescapable shock in an effort to establish the relationship between this factor and subsequent interference. One procedure involved variation in the temporal form of inescapable shock as a means of producing different levels of intrashock activity (Crowell, Lupo, Cunningham, & Anderson, 1978; Lawry, Lupo, Overmier, Kochevar, Hollis, & Anderson, 1978). A rapidly interrupted (i.e., pulsating) dc shock produced sustained levels of intrashock movement, whereas a noninterrupted (i.e., continuous) shock resulted in the development of relative immobility during shock. In another procedure (Anderson, Crowell, Cunningham, & Lupo, 1971), a passive-escape paradigm was employed for one group to reduce activity levels during pulsating shock below those exhibited by subjects in a yoked condition comparably exposed to inescapable shock. With both of these procedures, a negative relation was observed between movement during the initial shock treatment and magnitude of later interference with escape-avoidance learning. The results of these studies were interpreted by Anderson et al. (1979) as support for the view that, through learning or some related process, rats may develop immobility tendencies in the presence of shock stimuli during the initial treatment. Such reactions, if they recurred during test shock, would be expected to compete with the active responding required by the escape-avoidance task.
EXPERIMENT 1One implicat...