Delivered inescapable electric shock to freely moving wild rats (N = 10 and 15) in the presence of familiar and novel inanimate targets. It was found that: (a) in response to shock, Ss rarely attacked a familiar target but would readily attack a novel one; (b) amount of escape-directed behavior in response to shock decreased as the result of introducing a novel target into the shock situation; and (c) in a choice situation, both proportion of attacks directed toward a novel target, as compared with a familiar one, and number of attacks directed toward the novel target decreased with increased exposure to the novel target. (PsycINFO Database Record (c) 2006 APA, all rights reserved)