Harmless bodily pleasures are moralized because they are perceived as reducing self-control and cooperativeness.

Why do many people morally condemn unrestrained indulgence in bodily pleasures-such as gluttony, masturbation, and drinking alcohol-even when these behaviors do not harm others? Leading theories of moral cognition claim that these puritanical moral judgments are independent of cognitive adaptations for reciprocal cooperation. In five pre-registered experiments (N > 3000), we test an alternative hypothesis: that puritanical moral judgments emerge from perceptions that bodily pleasures indirectly facilitate free-riding by impairing self-control. In Studies 1 and 2a-b, participants judged that targets who increased (vs. decreased) their non-other-harming sex, food, alcohol, and inactivity would become more likely to cheat, an effect mediated by the perception that they would become less self-controlled. In Study 3, participants judged that relaxing regulations on sex, food, and alcohol in a village would decrease self-control and cooperation in the village, although they judged enforcing puritanical prohibitions even more negatively. In Study 4, participants expected that, in a scientific experiment, a treatment group made to increase their consumption of bodily pleasures would become less self-controlled and more likely to cheat than a psychologically similar control group. Across all studies, the perception that indulgence reduces self-control and cooperativeness was associated with the moral condemnation of harmless bodily pleasures. This provides support for the idea that some purity violations, although they do not directly harm other people, may be morally condemned because they activate cognitive systems designed for reciprocal cooperation.