One Size Does Not Make All Happy: Idionomic Links Between Striving for Positive States and Happiness in Experience Sampling

Striving for happiness can sometimes increase happiness but can also backfire and reduce it. To explore this paradox, we used idionomic methods—balancing individual-level analysis with group-level generalization—to examine how striving for happiness influences momentary happiness. Our data included ecological momentary assessment (EMA) surveys ( n  = 2251) from 167 participants (75.6% female; M age = 23.96, SD = 8.7). Each individual’s data were first modelled separately, producing their own estimate and standard error for the association between each striving item and each affect item. These idiographic estimates were then submitted to a multivariate random-effects meta-analysis, which revealed high, non-random heterogeneity. The type of striving—prioritizing positivity (PP) versus experiential attachment (EA) to enjoyment moderated the overall effect. Due to high heterogeneity in the overall effect, we applied group-based multivariate trajectory modelling. This revealed two distinct groups with nonlinear patterns across striving and affect. Multilevel vector autoregressive models showed that EA consistently dampened happiness within-person, despite no between-person association. In contrast, PP was linked to higher happiness in one group, but in the other, it had no direct benefit and indirectly reduced happiness via its connection to EA. The dampening effects of EA held even when accounting for stress, positive events, loneliness, and social connection. Our findings underscore the importance of combining within-person and between-person analyses by replicating known nomothetic effects and highlighting complex subgroup dynamics. This dual approach is a crucial and necessary advancement for modern happiness research.