Preexposure to contextual stimuli: Effects on startle responding in humans

Abstract

Previous research with rats has shown that preexposure to the contextual stimuli of the experimental situation results in facilitated habituation of the startle reflex. These findings support the predictions of nonrepresentational theories of habituation (e.g., Groves & Thompson, 1970), and oppose the predictions of representational theories (e.g., Wagner, 1976). The current experiment was designed to test whether the same results could be obtained with humans. Twentyfour hours prior to the habituation test, one group of subjects (E-P) was exposed to the contextual stimuli of the experimental situation, a second group (C-E) was exposed to different contextual stimuli, and a third group (C-N) received no pretreatment. The habituation test consisted of two sessions of 15 startle-eliciting noise bursts. The P-E group responded less on the first trial of Session 2. This finding is suggestive of greater long-term response decrements in this group, and thus supports the nonrepresentational theories of habituation.