Public Goods Game

Study cooperation, free-riding, collective welfare, and incentive design.

Public Goods Round

Your payoff0
Group total0
Average contribution0
Rounds0
Ready.

How this teaches game theory

Public-goods games model the tension between private incentives and collective welfare. Contributing benefits everyone, but each player may prefer to keep their own endowment and free-ride on others.

Complete scenario, mode, level, and concept guide

Scenarios

Basic public good

All contributions are multiplied and shared equally. Individual incentives can conflict with the group's best outcome.

Threshold project

The group receives a large public benefit only if total contributions reach a target.

Contribution with punishment

Very low contributors lose a small penalty, illustrating how institutions can change incentives.

Modes and levels

SettingMeaning
Human vs Computer groupYou choose one contribution; three bots choose theirs.
Human-controlled groupYour slider sets a common experimental contribution for all four players, useful for welfare comparisons.
Computer simulationAll four contributions are generated automatically.
Level 1Bots contribute generously.
Level 2Bots mix low, medium, and high contributions.
Level 3Bots reduce contributions when recent group contributions are high, demonstrating free-riding pressure.
Observe: compare your private payoff with total group welfare. A personally profitable deviation can make the group worse off.