How can the beneficiaries of collective action be persuaded to contribute the resources (time, energy, money) necessary for the effort to succeed? Rational and selfish players will recognize they can free ride on the successful contributions of others. If the effort is not successful, they will lose a contribution—and be “suckered.” Other than relying on altruism, organizers of the group effort can modify incentives so that players are more prepared to contribute. Laboratory experiments offer one way of assessing the effectiveness of various such modifications; we conducted such tests to see how well contributing is promoted by (1) assuring contributors that they will not lose if the group effort fails (a “money-back guarantee”) and (2) enforcing contributions if it succeeds (“fair share”). We expect the latter to be more successful because it is “stable,” unlike the former, whose success can be undermined by expectations of that success. Three experimental replications demonstrate that the money-back guarantee is no more successful than a standard dilemma, but fair-share requirements increase contributing significantly over that base. Analysis of subjects' expectations about others' behavior offers some support to the hypothesized process undermining the money-back guarantee, but motivational factors must also be taken into account for a full explanation.
Do Allies Really Free Ride?
