ExpEcon

Each player picks a number, and the target is a fraction of the class average. Points depend on the distance from the target, so the game can be repeated and the convergence of guesses tracked round by round.

Pairs choose between two actions at the same time, round after round, with the same partner or a new one each round. Payoffs are adjustable, with presets for the stag hunt and chicken, and partners can chat.

Any two-player game in strategic form with up to four actions each. Enter your own payoff table or start from matching pennies, the battle of the sexes, hawk and dove, an entry game, or rock, paper, scissors.

The ultimatum game, the dictator game, and alternating offers over a shrinking pie. Pairs play move by move, and every offer and response is recorded.

An investor sends money that is multiplied on the way, and a trustee decides how much to return. A gift-exchange variant pairs an employer’s wage with a worker’s effort.

Two players take turns to take the larger of two growing piles or to pass the decision on. The number of nodes, the piles and their growth are adjustable.

Members of a group divide an endowment between themselves and a common pot that is multiplied and shared. Options add a threshold that the pot must reach, or a stage of costly punishment.

Depositors of a common bank choose to withdraw early or to wait. Waiting pays more unless too many others withdraw. Bank size and payments are adjustable.

Firms in a market compete in quantities or in prices, with Cournot, Stackelberg, and Bertrand competition for identical or differentiated products. Each firm has a profit calculator.

The traveller’s dilemma, the 11–20 money request game, and the minimum effort game. Each player names a number, and the payoff depends on how it compares with the others’.

First-price, second-price, English, Dutch and all-pay auctions, with private values, a common value with private signals, or a value known to all. The host page plots bids against values with the equilibrium benchmark.