JOURNAL OF RESEARCH IN PERSONALITY 31, 523–542 (1997) ARTICLE NO. RP972191 Humor As a Stress Moderator in the Prediction of Blood Pressure Obtained during Five Stressful Tasks Herbert M. Lefcourt University of Waterloo Karina Davidson University of Alabama Kenneth M. Prkachin University of Northern British Columbia and David E. Mills Scientific Laboratory, New Mexico Health Department In five consecutive stressful tasks we examined the role of humor as a potential stress moderator using systolic and diastolic blood pressure as an indication of car- diovascular reactivity. In all five tasks, the Coping Humor Scale interacted with sex in the prediction of blood pressure. The same pattern was found in response to each of the five tasks: Females who were higher in coping humor exhibited lower systolic blood pressure than females scoring lower on coping humor, while the reverse char- acterized males; males who scored high on the coping humor scale exhibited higher systolic blood pressure than males scoring low on that scale. Similar though less robust results were found when the Situational Humor Response Questionnaire was used as the measure of humor. In the Cold Pressor Task, which involves pain and endurance, interactions were found between humor, sex, and trials indicating a stress-moderator effect. The absence of interactions indicating stress moderation in most of the analyses with the other four stress tasks suggests that humor may play This research was supported by Social Sciences and Humanities Research Council Grant 410-91-0773 to H.M.L. and by Grant T1513 from the Heart and Stroke Foundation of Ontario to K.P. and D.M. Reprint requests should be sent to Herbert M. Lefcourt at Department of Psychology, Uni- versity of Waterloo, Waterloo, Ontario N2L 3G1, Canada. 523 0092-6566/97 $25.00 Copyright  1997 by Academic Press All rights of reproduction in any form reserved.