Social modelling of health behaviours: Testing self-affirmation as a conformity-reduction strategy

OBJECTIVES: Social conformity negatively affects health. Exposure to peers who model unhealthy alcohol or food consumption increases personal consumption. Self-affirmation alters processes related to the motivations underlying conformity. We therefore tested whether self-affirmation reduces conformity to unhealthy behaviour and does so by reducing affiliation needs and/or increasing self-regulation. DESIGN: In two studies, participants were randomized to one of four conditions in a 2 (low vs. high peer modelling) × 2 (self-affirmed vs. not) design. METHODS: In Study 1 (N = 153), a confederate modelled low or high alcohol consumption. Participants' alcohol consumption was recorded; mimicry of confederates' sips was coded. In Study 2 (N = 122), written information indicated others' snack food intake during the study. Participants' food consumption was recorded. Affiliative interest was assessed in both studies. Inhibitory control and private self-awareness were assessed in Studies 1 and 2, respectively. RESULTS: In Study 1, participants exposed to heavy drinking consumed significantly more alcohol and mimicked the confederate more frequently than participants exposed to the light drinking model. Self-affirmation did not reduce this tendency, nor did it affect affiliative interest or inhibitory control. Exploratory analysis supported that mimicry mediated the peer modelling-consumption relationship. In Study 2, participants ate more when they believed others had eaten a lot, as opposed to little. Self-affirmation did not reduce this tendency and did not affect affiliative interest. Self-affirmed participants had higher private self-awareness than those who were not self-affirmed, but self-awareness did not affect consumption. CONCLUSION: Peer behaviour strongly influences personal consumption. Self-affirmation did not reduce behavioural conformity. Statement of contribution What is already known on this subject? Exposure to peers who engage in high consumption of alcohol and unhealthy foods is associated with increased personal consumption. Few studies have examined strategies to reduce conformity to consumption behaviours. What does this study add? Across two studies, self-affirmation did not reduce behavioural conformity, despite its' positive effects on private self-awareness. Conformity in face-to-face interactions is largely driven by mimicry.