Visual stimuli in distraction strategies for increasing pain tolerance. The confounding of affect with other stimulus characteristics.

Recent experimental studies in pain control have questioned the value of pleasant affect in strategies employing distraction. It appears that pleasant affect may have been systematically confounded with task complexity or novelty in past research that found pleasant imagery or slides effective in increasing pain tolerance with the cold pressor test. The present study was a follow-up to a study conducted by this author (Greenstein, 1984) in which unpleasant slides had significantly increased pain tolerance above pleasant slide level. In the present study, 69 college students (35 females, 34 males) rated either the pleasant or unpleasant slides used in the original study on their perceived pleasantness, complexity, and uniqueness (novelty). Results indicated that the unpleasant slides were rated significantly more complex (P less than 0.001) and unique (P less than 0.001) than the pleasant slides. Additionally, as in the earlier study, ratings of the unpleasant slides on pleasantness deviated significantly farther from neutrality than did ratings of the pleasant slides (t = 5.04, P less than 0.001). Thus the unpleasant slides were also perceived as being more significant (i.e., pertinent) than were the pleasant slides. The results indicate that affect was confounded with other stimulus characteristics in the Greenstein (1984) pain control study and probably in a significant number of other studies as well. Researchers are cautioned to control for the stimulus characteristics of visual distraction strategies used in pain control studies. The assumption that pleasantness, per se, contributes to strategy effectiveness is no longer tenable; future research must demonstrate an independent effect.(ABSTRACT TRUNCATED AT 250 WORDS)