Imagine a situation where N offenders face punishments of ten years for a crime. If one of them confesses, that person gets one year term, and the rest are released. So everybody has an incentive for confession (a reduction of nine years imprisonment) or nothing (going free if at least one of them – the volunteer – admits).
In game theory language, the payoff matrix is as follows for the two players.
| Volunteer’s Decision | |||
| Do volunteer | Don’t volunteer | ||
| Other’s decision | Do volunteer | -1,-1 | -1,1 |
| Don’t volunteer | -1,1 | -10,-10 |
There are a lot of examples in real life where the volunteer dilemma operates, albeit, to the detriment of the community. A famous one is the bystander effect – a group of people witness a crime in which someone is stabbed. Everyone hesitates to call for help, fearing some cost (questioning by police or the possibility of getting into the criminal’s watchlist). At the same time, they all sincerely hope someone volunteers and help the person getting the treatment.
It is not difficult to understand that the chance that no one calls increases as the cost of volunteering increases. But what is surprising is the lowered probability of getting help as the number of bystanders increases.
References
Andreas Diekmann, Volunteer’s Dilemma, The Journal of Conflict Resolution, 1985, 29(4), 605
William Spaniel, The Murder of Kitty Genovese (Volunteer’s Dilemma): Youtube
