This small and preliminary study yielded some expected as well as some unexpected results. As expected, based on clinical experience and the literature with adults, humorous videos were found to be useful in increasing tolerance for a moderately painful stimulus. The increase was robust enough to be statistically significant even with such a small sample, and enough time longer to suggest that such an intervention would be of some clinical utility. What was surprising was that this increased tolerance was not associated with a change in pain severity appraisal. Subjective ratings of pain did not change over the three trials, despite a marked increase in tolerance during the third trial. The number of laughs was also not associated with pain severity appraisal or with pain tolerance. The mechanism by which the humorous videos increase pain tolerance thus appears not to be through changes in the cognitions of pain appraisal or through the actual physical effects of laughter.
Studies of adults have found that emotionally engaging video segments were equally effective in increasing pain tolerance, whether the videos were funny, sad or frightening. The primary mechanism has therefore been interpreted as a compelling and emotional distraction from the pain leading to increased tolerance (16–18
). Since only humorous videos were used in this study, this hypothesis was not evaluated. Indeed, it is not clear that the IRB would allow such a study with children. It is difficult to imagine parents or medical personnel being eager to use frightening or sad videos as distraction for children, particularly those undergoing painful procedures. Thus, even if such videos might be equally distracting, they would not be of clinical utility for helping children deal with expected and necessary pain.
For those who do humorous interventions with children who are sick or in pain, these findings do suggest that the primary objective is to engage the child, and that this can be effective whether or not the child actually laughs out loud. This implies that even children who are reserved in their expressions of emotion or whose illnesses limit their ability to laugh out loud can have benefit from engaging, humorous interventions. The interventions also may be of help even if the child does not report a subjective decrease in pain appraisal. As appears to be the case with some pain medications, the effect of the humorous video may be to decrease the distress or suffering or enhance coping rather than impact the actual sensation of the pain.
The study was successful in its goals to establish feasibility of this type of study and to help outline some further questions to be explored. Nonetheless, there are some significant limitations to this study. It was a pilot study, with a small sample size and significant potential confounds. The small sample size precluded analysis of variables known to be important to pain severity appraisal and pain behavior such as gender, intelligence, socioeconomic status and age. The order of the trials was not varied between subjects, also due to the small sample size. This opens the question of whether the increase in pain tolerance is due to an accommodation to the stimulus. The lack of difference between Trial 1 and Trial 2 suggests that there was not a significant accommodation between these trials. Previous studies from this laboratory using a counterbalanced design found no impact of order in response to the cold pressor for the first, second or third task in the lab setting. However, lack of counter-balancing the trials among the subjects remains a limitation, a factor suggesting a need for replication of the study with a larger sample. The results must be viewed as preliminary.
Clinically, the results of this study support the ongoing efforts to provide humorous distraction for children undergoing painful procedures. Laughter itself may be less important than the emotional involvement in humor. Even the expectation of humor may have a positive effect. One published study of adults found that expectations that a specific distracter would be helpful were associated with an increased threshold for discomfort (19
). It is possible that an additional component which added to the pain tolerance in the third trial was that the children were able to view a video which they had already seen, and chose to see again, creating a positive expectation for enjoyment.
This study was conducted with healthy children. Thus, it would appear to be applicable to healthy children going through painful procedures, such as diagnostic tests or preventative interventions. It is not clear whether or not these findings could be generalized for children who are ill. Anecdotal evidence suggests that humorous interventions are well-received by children in the hospital, and that other types of distracters are useful for children undergoing painful procedures. Further study is indicated to understand the best way to use humorous interventions for ill children as well as the mechanism of the effect.
Future suggested studies include investigations of differences in pain tolerance in both healthy and ill children in response to various activities, including
- passive humor (e.g. watching funny videos),
- active or interactive humor (e.g. telling jokes, or doing funny things),
- passive distraction (e.g. watching drama or action videos), or
- active distraction (e.g. playing video games).