Habituation of the Orienting Response: A Gating Mechanism Subserving Selective Attention

The purpose of this investigation was to determine whether prior habituation of the phasic orienting response (OR) to stimuli which were later to be used as distractors in an attention demanding task, would improve task performance and reduce OR frequency to distractors during the task. The task was the solution of mathematical problems from immediate memory, and the distractors were random numbers and mathematical signs. Subjects were sequentially assigned to one of four conditions: 1) 15 presentations of distractors, problems with distractors; 2) 15 presentations of a tone, problems with distractors; 3) problems with distractors; and 4) 15 presentations of distractors or tone, problems without distractors. Results clearly indicated that prior habituation of the phasic OR to the distractors improved performance relative to no prior habituation or to prior habituation to a tone. There was also evidence of decreased OR activity during problem solving in the prior habituation group relative to the tone habituation and no habituation groups. The data supported an hypothesis that selective attention consists of at least two processes: 1) sensitization of phasic and tonic ORs to salient stimuli, and 2) habituation of phasic and tonic ORs to irrelevant stimuli.