THE HUMAN ORIENTING REACTION AS A FUNCTION OF ELECTRODERMAL VERSUS PLETHYSMOGRAPHIC RESPONSE MODES AND SINGLE VERSUS ALTERNATING STIMULUS SERIES.
INDIANA UNIV BLOOMINGTON
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Eighty Ss were presented with 300-msec. tones and lights separated by a mean interval of 45 sec. and arranged in 40-trial sequences which contained both repeated single and alternating patterns as well as trials constituting changes from these patterns. GSR and digital-blood-volume-pulse-change VPC were recorded. Both responses increased reliably after a stimulus change from single repetition, p .001, but not after change from alternation, F 1. For trials 1-15 the GSR habituated reliably and at the same rate to both repetition patterns, p .001, but the VPC did not habituate to either pattern, F 1. A continuous time-estimation task given to half the Ss in order to distract them from the stimuli did not affect the above results. Assuming the GSR and VPC to be components of the orienting response OR, these findings create difficulties for OR and related theories of autonomic behavior. Author