In Defense of the Commons: Young Children Negatively Evaluate and Sanction Free Riders.

Human flourishing depends on individuals paying costs to contribute to the common good, but such arrangements are vulnerable to free riding, in which individuals benefit from others' contributions without paying costs themselves. Systems of tracking and sanctioning free riders can stabilize cooperation, but the origin of such tendencies is not well understood. Here, we provide evidence that children as young as 4 years old negatively evaluate and sanction free riders. Across six studies, we showed that these tendencies are robust, large in magnitude, tuned to intentional rather than unintentional noncontribution, and generally consistent across third- and first-party cases. Further, these effects cannot be accounted for by factors that frequently co-occur with free riding, such as nonconforming behaviors or the costs that free riding imposes on the group. Our findings demonstrate that from early in life, children both hold and enforce a normative expectation that individuals are intrinsically obligated to contribute to the common good.