title: Effects of instruction on acquisition and extinction of electrodermal responses to fear-relevant stimuli.
abstract: In the present study we examined the hypothesis that electrodermal responses conditioned to fear-relevant stimuli are insensitive to verbal instructions. In the first experiment, different groups of subjects were conditioned to fear-relevant and fear-irrelevant control stimuli in a long interstimulus interval differential paradigm with shock as the unconditioned stimulus. Then half of the subjects were informed that no more shocks would be presented, and a number of extinction trials followed. The instruction completely abolished responding to fear-irrelevant stimuli, while leaving responses to the fear-relevant stimuli unaffected. In the second experiment, subjects were "conditioned" to fear-relevant or irrelevant stimuli by an instruction involving threat of shock. This manipulation potentiated potentiated responses to fear-relevant stimuli significantly more than responses to fear-irrelevant stimuli. Thus, instruction had a symmetrical effect on acquisition and extinction to fear-irrelevant stimuli, whereas it facilitated acquisition but was ineffective in reducing responding to the other class of stimuli. These results are related to a preparedness theory, and their relevance for an understanding of phobias is discussed.
mesh_terms: D000328:Adult; D003216:Conditioning, Operant; D003213:Conditioning, Psychological; D004597:Electroshock; D005108:Extinction, Psychological; D005239:Fear; D005260:Female; D005712:Galvanic Skin Response; D006801:Humans; D008297:Male; D008875:Middle Aged; D010698:Phobic Disorders / Q000209:etiology; D014796:Visual Perception