The benefits of need satisfaction depend on their relative importance for people with a unidimensional identity: an idiographic analysis

Self-determination theory proposes that the satisfaction of basic psychological needs is equally beneficial for everyone – the Universal Hypothesis . Equally, there are intra-individual differences in how the satisfaction of differentially important needs might be differentially beneficial, which we term the Intra-individual Hypothesis . We aimed to reconcile these positions. Across four cross-sectional studies ( n s = 300 rock climbers, 323 sportspeople, 394 UK and Chinese adults, 320 UK adults), we investigated the needs of individuals with varying dimensions to their identity, and their motivation and self-esteem. In Studies 1, 2, and 4, when individuals strongly related their sense of identity to investment in a specific activity, the association between need satisfaction and self-esteem (and motivation in Studies 1–2) depended on their intra-individual need importance, supporting the Intra-individual Hypothesis . In Studies 3 and 4, for individuals with a multidimensional identity, the association between need satisfaction and self-esteem did not depend on the importance of each need, supporting the Universal Hypothesis . The satisfaction of basic psychological needs is not always uniform in its link with motivation and well-being. The degree to which individuals have a unidimensional or multidimensional self-concept appears fruitful in predicting the relative value of the Universal Hypothesis and the Intra-individual Hypothesis .