The effects of imagery and sensory detection distractors on different measures of pain: how does distraction work?

Two experiments compared the effects of different distraction tasks on pain. Based on multiple-resource theory, Expt 1 predicted that the more a distractor shares processing resources with pain perception the greater the interference between the two. Experiment 2 tested whether the emotional content of the distractor would differentially effect measures that are supposedly reflective of the affective component of pain.

Both experiments used repeated measures designs, with counterbalanced distraction conditions.

In Expt 1 20 participants indicated their pain threshold. No instructions, or one of three distraction conditions were presented across four blocks of potassium iontophoresis. The distractors were: thermal and light detection, and neutral imagining. In Expt 2 30 participants had three blocks of pain threshold, pain tolerance, and pain rating trials. For threshold, tolerance, and rating trials, one block was without distraction, a second block was completed during light detection, and a third block while imagining an enjoyable holiday.

In Expt 1 all the distractors increased pain threshold. The two detection tasks were similarly effective, and more so than the imagination task. Performance on the two detection tasks was impaired by painful stimulation similarly for both tasks. In Expt 2 the visual detection distractor increased pain threshold and tolerance and reduced pain ratings while pleasant imagery only increased pain threshold.

These results indicate that a task that requires attention to external cues has more impact on pain than either a positive or neutral imagination task. However, it is not clear that the specific resources used by the distraction tasks moderated pain differentially as predicted by multiple-resource theory.