In a classic lab game, almost nobody is the pure free-rider economic theory predicts
In the public goods game, each player privately decides how much of their own money to contribute to a shared pot, which is multiplied and split evenly among everyone regardless of who paid in. Pure self-interest predicts everyone contributes zero — yet in experiment after experiment, most people contribute something, though average contributions reliably erode over repeated rounds as free-riders go unpunished.