Sustaining humanitarian engagement: A reinforcement account of helping over time

Sustaining prosocial behavior during prolonged crises is essential, yet its motivational drivers remain unclear. In a four-wave longitudinal study of Polish citizens aiding Ukrainian refugees ( N = 1066), we tested a dynamic model of sustained helping, focusing on psychological rewards—perceived benefits of helping, such as purpose, social connection, and reduced unease—and motivational importance, the value placed on fulfilling core psychological needs. Using cross-lagged panel (CLPM) and random-intercept CLPM (RI-CLPM) models, we examined reciprocal associations among these constructs and helping effort. In the CLPM, psychological rewards and helping were reciprocally associated over time, consistent with a reinforcement account. Motivational importance predicted initial, but not sustained, engagement. RI-CLPM results revealed strong trait-like stability across constructs, suggesting that sustained helping is primarily driven by enduring individual differences in motivational orientation rather than short-term within-person fluctuations. These findings indicate that psychological rewards are more closely linked to sustained helping than motivational importance, and that this association operates mainly at the between-person level. Our results refine accounts of prosocial motivation and inform strategies for maintaining engagement during humanitarian crises.