Mancur Olson

In 1965, Mancur Olson published a book that overturned a century of assumptions about how groups behave. The core argument of The Logic of Collective Action was disarmingly simple: rational individuals will not voluntarily contribute to the provision of a public good, because each can enjoy the benefits whether or not she bears the costs of providing them. The free-rider problem was not new, but Olson's demonstration that it applied to every organized group—unions, professional associations, political parties, social movements—was devastating, because it meant that shared interests do not naturally produce collective action. They produce, instead, the small-group advantage: organized action emerges reliably only from groups small enough that each member's contribution is visible, the social pressure is effective, and the share of collective benefit large enough to justify the cost of participation. Large groups fail—not because their members are selfish, but because the structure of incentives makes rational individual