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Predictable and unpredictable aversive events: Evidence for the safety-signal hypothesis


GSR was compared in two groups exposed to either predictable or unpredictable aversive stimuli. Spontaneous fluctuation (SF) of skin resistance was the primary variable measured because it is unconfounded by attentional responses elicited by experimental stimuli. The unpredictable group showed nearly twice as many SFs as the predictable group. Amplitude of GSR occurring within 0–4 sec after onset of the aversive stimulus differentiated between groups, but amplitude of GSR occurring within 4–8 sec after onset did not. The results, discussed in terms of Seligman’s safety-signal hypothesis, indicated that arousal is greatest for the unpredictable group during intertrial intervals rather than during the presentation of the UCS.


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This study was supported in part by Grant OEG-2-700041 from the Office of Education awarded to the junior author.

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Price, K.P., Geer, J.H. Predictable and unpredictable aversive events: Evidence for the safety-signal hypothesis. Psychon Sci 26, 215–216 (1972).

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  • Aversive Stimulus
  • Aversive Event
  • Dead Body
  • Orienting Response
  • Skin Resistance