Autonomous Motives Foster Sustained Commitment to Action: Integrating Self-Determination Theory and the Social Identity Approach.

Social change movements may take years or decades to achieve their goals and thus require ongoing efforts from their supporters. We apply the insights of self-determination theory to examine sustained collective action over time. We expected that autonomous motivation, but not controlled motivation, would predict sustained action. We also examine whether autonomous motivation shapes and is shaped by social identification as a supporter of the cause. Longitudinal data were collected from supporters of global poverty reduction ( N = 263) at two timepoints 1 year apart. Using latent change score modeling, we found that increases in autonomous motivation positively predicted increases in opinion-based group identification, which in turn predicted increases in self-reported collective action. Controlled motivation (Time 1) negatively predicted changes in action. We concluded that autonomous motivation predicts sustained action over time, while promoting controlled motives for action may backfire because it may undermine identification with the cause.