Matrix: Instructor Specified

Game Description

MobLab's Matrix games allow you to specify the payoff matrix for a two-player normal-form (i.e. simultaneous-move) game. Each player can have two to four actions, and the number of row actions need not be the same as the number of column actions. This game can be used to represent a wide variety of two-player interactions by simply modifying the payoff structure.

Players are paired, with one assigned the role of the Row player, and the other the Column player. If you specify multiple rounds, both pairs and player roles are fixed. After each player makes her choice in each round, outcomes are revealed, and players move to the next round.

Brief Instructions

In addition to specifying the number of actions for each player and payoffs in each cell, you can specify the name of each action and the text that appears on on the rules page of the player’s game screen. Figure 1 shows the game screen for a student whose instructor configured a 2×3 matrix.

Figure 1: Game Screen

Key Treatment Variations

Repeat play often results in markedly different outcomes than one-shot interactions.

To have each pair interact repeatedly, set Minimum Rounds. For indefinite repetition, once Minimum Rounds has been reached, Ending Probability establishes the likelihood of proceeding to another round conditional on reaching the current round.

For one shot play, set Minimum Rounds to 1 and keep Ending Probability at 100. To have students play multiple rounds with re-pairing between rounds, click Replay after a one-round game. Choose Random to randomly assign both roles and partners in the next game.


At the top of the results page, we depict the payoff matrix (Figure 2). This may be helpful in establishing the multiple equilibria in pure strategies.

Figure 2: Payoff Matrix

To show the likelihood of equilibrium play across rounds, we display the frequency of each outcome for each round (Figure 3, revealed by clicking the triangle next to Outcome Frequencies).

Figure 3: Outcome Frequency

Next, we display for each round the frequency of each action (Figure 4, revealed by clicking the triangle next to Action Frequencies). You can reveal or hide the results for an action by clicking entry in the legend.

Figure 4: Action Frequency

Robot Play

Robots (i.e., automated players) randomly choose among available strategies.

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