A Randomized-Controlled Trial of Social Norm Interventions to Increase Physical Activity.

BACKGROUND: Physical activity confers numerous health benefits, yet few adults meet recommended physical activity guidelines.

PURPOSE: The impact of brief messages providing descriptive and injunctive social norm feedback on physical activity was tested in this conceptual pilot study.

METHODS: Young adults (N = 111) were randomly assigned to one of three conditions: descriptive norm feedback, descriptive-plus-injunctive norm feedback, or no social feedback (control condition). Participants used pedometers for eight weekdays and recorded their step counts each evening. The descriptive norm group received feedback about the average number of steps taken by group members the previous day. The descriptive-plus-injunctive norm group received feedback about the group average, as well as a sad face if the participant was below the average or a happy face if the participant was above the average. The control group received no feedback throughout the study.

RESULTS: By days 7 and 8, the descriptive-plus-injunctive norm group reported significantly more steps relative to the control group, whereas the descriptive norm group showed a trend toward higher step counts relative to the control group. These effects did not differ for participants above versus below the group average at baseline.

CONCLUSION: The combined use of descriptive and injunctive social norms increased physical activity over a short period. This simple feedback strategy has potential for achieving wide reach and dissemination on its own or combined with more comprehensive interventions. This initial evidence can guide larger trials of longer duration.

TRIAL REGISTRATION NUMBER: The trial was registered with the ClinicalTrials.gov database (NCT02710201).