A cognitive appraisal of threat is believed to intervene between the appearance of a stressful stimulus and a stress reaction to the stimulus. The effect of a "rational" treatment on the appraisal of threat is investigated. Five groups of 13 college students each heard one of five treatment orientations before viewing slides showing the victims of automobile accidents. Subjects were divided into the following treatment groups: rational, content-denial, mystification, suppression, and control. While subjects viewed the slides, their heart rates and endosomatic skin potentials were monitored and self-reports of distress were obtained. A measure of avoidant behavior was obtained after the slide presentation. The results of the self-report measure indicated that the "rational" and"suppression" treatments led to significantly lower self-reports of distress than the other conditions. This suggests that "rational" treatment is effective in altering the appraisal of threat. These findings were not supported by physiological and behavioral measures. (Author/JLL)