Interaction of intensity and order regarding painful events.

While stimulus intensity obviously affects degree of pain responding, presentation order effects of stimuli of different intensities on acute pain responses are under-researched. The present study examined the effects of manipulating presentation order of lower and higher pain stimulus intensity. Using 96 undergraduates, this investigation employed a 2 x 2 mixed research design, with pain stimulus sequence as a between-subjects variable and pain stimulus trial as a repeated measure.