Why do people support economic redistribution? Hypotheses include inequity aversion, a moral sense that inequality is intrinsically unfair, and cultural explanations such as exposure to and assimilation of culturally transmitted ideologies. However, humans have been interacting with worse-off and better-off individuals over evolutionary time, and our motivational systems may have been naturally selected to navigate the opportunities and challenges posed by such recurrent interactions. We hypothesize that modern redistribution is perceived as an ancestral scene involving three notional players: the needy other, the better-off other, and the actor herself. We explore how three motivational systems-compassion, self-interest, and envy-guide responses to the needy other and the better-off other, and how they pattern responses to redistribution. Data from the United States, the United Kingdom, India, and Israel support this model. Endorsement of redistribution is independently predicted by dispositional compassion, dispositional envy, and the expectation of personal gain from redistribution. By contrast, a taste for fairness, in the sense of (i) universality in the application of laws and standards, or (ii) low variance in group-level payoffs, fails to predict attitudes about redistribution.[M]ore recently the "Greatest happiness principle" has been brought prominently forward. It is, however, more correct to speak of the latter principle as the standard, and not as the motive of conduct.-Charles Darwin (1) W hy do people support social policies? One level of explanation addresses properties of populations that individual minds might process-local practices, shared beliefs and ideologies, collective identities, and recent history (2). A second, independent level of explanation asks which specific psychological mechanisms participate in forming the individual's response to a policy-that is, what interpretive, emotional, and motivational systems are activated by external inputs, shaping the response (3, 4). Here, we explore this second level of explanation. We investigate several evolved psychological mechanisms to see to what degree they pattern the individual's response to economic redistribution. We also investigate the extent to which a taste for fairness shapes support for redistribution.By economic redistribution, we mean the modification of a distribution of resources across a population as the result of a political process. In the case of progressive redistribution (henceforth, redistribution)-a policy for which there is large worldwide demand (5, 6)-the ostensible group-level goal is to even out a skewed statistical distribution by transferring resources from the better off to the less well off. However, it is possible that the public rationale for supporting a policy is distinct from the private or even nonconscious motives of individuals supporting (or opposing) it. It is important to recognize that such a transformation in the distribution of resources does not necessarily entail conservation of a fixed and ...