Who helping helps: An event-sampling study of how basic psychological needs moderate the impact of acting prosocially

Growing work suggests that prosociality – actions such as kindness and generosity – boosts the well-being of altruists, yet this effect is not universally true for all individuals. Thus, a major question moving forward is who reaps the largest benefits of acting prosocially. Here, we propose that trait differences in satisfaction of needs (i.e. autonomy, competence, and relatedness) act as key moderators of the effect of prosociality on well-being. We tested two competing hypotheses – deprivation vs. sensitization models – in a 14-day event-sampling study of 383 community participants. We found that people with lower trait autonomy experienced a greater well-being boost after acting prosocially than their higher counterparts. Moreover, this relationship was further mediated by state autonomy. Our findings highlight the special role autonomy, but not competence or relatedness, plays in explaining individual differences in who benefits from acting prosocially – and the mechanism behind this process.