This program sets up a multiperson game in which each
person chooses whether or not to "volunteer." The payoff for all people in a
group is higher if at least one of them volunteers, but it only takes
one volunteer for the group benefit to be obtained. Moreover, a volunteer incurs
a cost that cannot be shared. The incentives are such that a person who
is only motivated by their own payoffs would
only want to volunteer if it is likely that nobody else will do so.
This is a classic social dilemma game that can evoke lots
of class discussion about diffusion of responsibility, strategy, etc.
     
The probability of volunteering should be
a decreasing function of group size, as implied by simple intuition and
from the mixedstrategy Nash equilibrium prediction.
This game is the topic of Chapter 15 in Holt (2006) Markets, Games, and
Strategic Behavior.

Vecon Lab  August 20, 2014 