Behavioral Compliance with Warnings: Effects of Stress and Placement

Research on the effectiveness of warnings has tended to focus on internal design aspects including variables such as the inclusion of various pictorials, color, and signal words. Only a few studies have examined the influence of warning-related variables that are external to the design of the warning itself although there have been some exceptions such as research on the effects of social influence and cost of compliance. Another potentially important external factor with respect to warning effectiveness is stress. Stress has been shown to influence the quality of decision-making and judgment formation in other domains. The present research examined the effects of stress and warning placement on compliance behavior. Participants were assigned randomly to one of four conditions in a 2 (Stress: lower vs. higher) x 2 (Warning Placement: as a posted sign vs. within a set of task instructions) between-subjects design experiment. In the higher stress condition, participants were given a time limit to complete the task, and during the task the experimenter stood immediately adjacent to the participant, appearing to be measuring and timing the participant's performance. Thus in this condition there were both time-pressure and social-evaluation stress. In the lower stress condition, participants were given as much time as they needed to complete the task and the experimenter stood at a distance, out of the participant's field of view. Participants performed a chemistry task in which they weighed and measured various chemical substances that appeared potentially hazardous, but were actually safe. A warning directing participants to wear mask and gloves while performing the task was present in one of the two locations. Compliance with the warning (wearing of protective equipment) was significantly higher among participants under lower stress and who were exposed to the within-instructions warning. The findings add to knowledge about the effects of external warning factors by showing that stress, such as that evoked in the present experiment, affects the extent to which warnings are complied with. Implications of these results are discussed.