The curvilinear effects of relative positions in smartphone app leaderboards on physical activity

To date, the nuanced effects of relative positions in leaderboards on health behaviors remain unclear. This study partly fills this void and aims to examine the effects of relative positions in smartphone app-based leaderboards on users’ physical activity. We propose and test a curvilinear effect in the form of a U shape. In Study 1 (n = 1,585), we use a survey-experimental design to manipulate 16 relative positions and a generalized additive model to test for the curvilinear effects on physical activity intentions. We find that intentions are higher at the top (ranks 1, 2, 3, and 4) and the bottom (85, 86, 87, and 88; 88 is the last rank) compared to upper to upper-mid (10, 19, 25, and 41) and lower to lower-mid (47, 63, 69, and 79) positions in the leaderboard. In Study 2 (n = 126), we use a behavior-experimental design to study changes in actual physical activity after individuals have been informed about their relative position in the leaderboard. Change in hand grip strength is used as an outcome. Again, we find evidence for U-shaped effects: physical activity increases among top-ranked persons (ranks 1 and 2) and bottom-ranked persons (87 and 88; 88 is the last rank) but there is a marginally significant decrease among persons ranked 25 and 69. The findings reveal that both top and bottom (vs. upper or lower mid) ranks in leaderboards may motivate individuals to become more active.