Effect of probe stimulus intensity on the dissociation between autonomic orienting and secondary probe reaction time
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Information processing accounts propose that autonomic orienting reflects the amount of resources allocated to process a stimulus. However, secondary task reaction time (RT), a supposed measure of processing resources, has shown a dissociation from autonomic orienting. The present study tested the hypothesis that secondary task RT reflects a serial processing mechanism. Participants (N = 24) were presented with circle and ellipse shapes and asked to count the number of longer-than-usual presentations of one shape (task-relevant) and to ignore presentations of a second shape (task-irrelevant). Concurrent with the counting task, participants performed a secondary RT task to an auditory probe presented at either a high or low intensity and at two different probe positions following shape onset (50 and 300 ms). Electrodermal orienting was larger during task-relevant shapes than during task-irrelevant shapes, but secondary task RT to the high-intensity probe was slower during the latter. In addition, an underadditive interaction between probe stimulus intensity and probe position was found in secondary RT. The findings are consistent with a serial processing model of secondary RT and suggest that the notion of processing stages should be incorporated into current information-processing models of autonomic orienting.
Australian Journal of Psychology
© 2001 Taylor & Francis. This is an electronic version of an article published in Australian Journal of Psychology Vol.3 (2), 2001, pp.72-76. Australian Journal of Psychology is available online at: http://www.informaworld.com with the open URL of your article.
PRE2009-Biological Psychology (Neuropsychology, Psychopharmacology, Physiologica
PRE2009-Learning, Memory, Cognition and Language