Interactive effects of the affect quality and directional focus of mental imagery on pain analgesia

College students (25 men and 25 women) were randomly assigned (within sex) to each of the 4 factorial groups, based on manipulation of affect quality (positive vs. negative) and directional focus (internal vs. external) of mental imagery, and to a control group receiving no manipulation. Both imagery variables had a significant impact on pain tolerance and ratings during a cold-pressor test with positive affect and external imagery producing greater analgesia than their counterpart conditions. Positive affect imagery combined with external imagery resulted in the lowest reported pain amongst the groups. However, self-reported mood descriptors did not consistently parallel the pain tolerance and rating data. Likewise, although heart rate and skin potential responses increased during the cold pressor for the group as a whole, the only significant difference amongst the experimental groups was the relatively higher skin potential reactivity of the positive affect-external imagery group--possibly reflecting greater task engagement for this group. Seemingly, imagery in this situation operates primarily via cognitive, rather than via physiological mediators of the pain experience.