The volunteer's dilemma explains the bystander effect

The bystander effect is the phenomenon that people are less likely to help others when they are in a group than when they are alone. The theoretical literature typically explains the bystander effect with the volunteer's dilemma: if providing help is equivalent to creat-ing a public good, then bystanders could be less likely to help in groups because they free ride on the other bystanders. This paper uses a dynamic game to experimentally test such strategic interactions as an explanation for the bystander effect. In line with the predic-tions of the volunteer's dilemma, I find that bystanders help immediately when they are alone but help later and are less likely to help if they are part of a larger group. In contrast to the model's predictions, subjects in need of help are helped earlier and are more likely to be helped in larger groups. This finding can be accounted for in an extended model that includes both altruistic and selfish bystanders. The paper concludes that the volun-teer's dilemma is a sensible way to model situations in which someone is in need of help, but it highlights the need to take heterogeneous social preferences into account. (c) 2020 Elsevier B.V. All rights reserved.

Automated summary

The bystander effect refers to the phenomenon where people are less likely to help others in a group than when alone, which can be explained by the volunteer's dilemma. Experimental findings support the prediction that bystanders are more reluctant to help in larger groups. However, individuals in need of help are actually assisted earlier and more often in larger groups, suggesting the influence of diverse social preferences.