Reactance to persuasive health messages as a function of message framing and message source

Abstract

Background: Persuasive health messages do not always have the intended health-promotional effect; they sometimes backfire and lead to unhealthier behavior. Such boomerang effects may be due to reactance (i.e. motivation to restore one's sense of self-determination after perceiving a threat to decisional freedom). The current study jointly investigates effects of message forcefulness and message source on reactance to a healthy eating message, and on subsequent healthy eating intentions. Methods: One-hundred-nineteen students were included in an experimental 2x2 between-subjects design. Participants were exposed to a supposed blog from either a peer (student) or a non-peer (elderly woman). The blog suggested replacing unhealthy snacks with healthier alternatives, using either controlling or autonomy-supportive language. Students subsequently reported level of reactance and healthy eating intentions. Baseline consumption of healthy snacks was controlled for. Results: Hayes’ macro for process analysis (model 7), showed that message forcefulness, but not source, significantly affected reactance (B = 0.71, p < .001). Moreover, reactance affected healthy eating intentions (B = -0.26, p = .004), mediating the relation between forceful language and intentions (B = -.18, SE = .07, CI [-.40, -.07]). Conclusion: Controlling language in a message promoting healthy eating induce more reactance than autonomy-supportive language, and increased reactance in turn led to lower healthy eating intentions. This has important implications for health promotion, as it suggests that using less forceful language may in fact promote the effectivity of health promotion messages. Our results also suggest that message source may be less influential in this regard.