Contradictory and complex health messages: an experimental test of different sources of uncertainty

ABSTRACT Contradictory and complex health messages are prevalent in the media and can lead to uncertainty in decision-making. We explore if the theoretical distinction between message contradiction and complexity is manifested in laypersons’ perceptions. U.S. adults (N = 584) were randomly assigned to one of three conditions: contradictory messages, complex messages, or no-message control. Participants in the message conditions read contradictory or complex messages and completed measures of perceived contradiction and complexity. All participants completed measures of issue uncertainty and decision uncertainty. The theoretical distinction between contradiction and complexity was not reflected in participants’ perceptions. Although participants rated contradictory messages as more inconsistent than complex messages, the complex messages were not rated as more complex than contradictory messages. Results supported a model in which perceptions of contradiction and complexity give rise to issue uncertainty, leading to decision uncertainty. The unique perceptions and effects of distinct sources of health-related uncertainty need further investigation.