Fig 1.
The volunteer’s dilemma (VOD) game from actor i’s perspective.
In the VOD, actor i chooses between sanctioning (C) and declining to sanction (D). If i chooses C, i incurs a cost Ki but earns Ui as the collective good is produced. If i chooses D, i’s payoff depends on what the other actors do. If all other actors choose D, the collective good is not produced and no one earns anything. If at least one of the other actors chooses C, the collective good is produced and i earns Ui. Since in a VOD Ui > Ki > 0, choosing D is not a dominant strategy, yet all actors prefer another actor to choose C while they choose D.
Table 1.
Experimental games and experimental design.
Table 2.
Predicted sanctioning probabilities.
Fig 2.
Stealing rates across experimental conditions.
Fig 3.
Predicted and observed sanctioning rates at the individual level across experimental conditions and subject roles.
Fig 4.
Predicted and observed sanctioning rates at the group level across experimental conditions.
(a) Sanction by at least one person. (b) Sanction by exactly one person].
Fig 5.
Predicted and observed sanctioning rates at the individual level across experimental conditions, subject roles and time.
Fig 6.
Predicted and observed sanctioning rates at the group level across experimental conditions and time.
(a) Sanction by at least one person. (b) Sanction by exactly one person.