Political ideology and moral dilemmas in public good provision.

Individuals often face dilemmas in which non-cooperation serves their self-interest and cooperation favors society at large. Cooperation is often considered the moral choice because it creates equality and fairness among citizens. Accordingly, individuals whose political ideology attaches greater value to equality than to agency and self-reliance should not only cooperate on more rather than less efficient public goods, but also more on public goods from which individuals benefit equally rather than unequally. We examine this possibility by comparing ideologically left-leaning and right-leaning individuals' cooperation on multiple public goods that varied in efficiency and (in)equality in returns. We find that left-leaning individuals cooperate more than right-leaning ones, but only on public goods that benefit everyone equally, and not more on public goods that generate inequalities. Left-leaning individuals also trust and expect others to cooperate more on equal- versus unequal-returns public goods, while self-identified right-leaning individuals do not differentiate between these. Interestingly, ideology does not predict which public good is deemed more morally appropriate to cooperate on. Results combined specify when and why self-identified leftists can(not) be expected to cooperate more than rightists and reveal how moral decision-making depends on structural elements of the public good provision problems that citizens face.