A Game-Theoretic Exploration of the Bystander Effect

by Niene Tempelman, Hester van der Weij, & Evelien van Meeteren
2645 words



Literature Review


           The Effects of a Criminal Record
           The Effects of a Reward




            “37 Who Saw Murder Didn’t Call the Police” is the headline of the New York Times on May 27, 1964 (Gansberg, 1964). The article describes the murder of Catherine Genovese, the most famous example of the bystander effect. In answer to her screams, lights lit up, people opened their windows, and one man shouted to leave her alone. The murderer left but returned shortly after the lights turned off and continued stabbing her. No one intervened, no one called the police. 35 minutes after the attack, the police were notified, but Catherine had already passed away (Gansberg, 1964). The lack of action by the witnesses was later explained by the following reasoning; all of the witnesses assumed someone else would help or notify the policy (Darley & Latané, 1968).

            The lack of help, in this case, can be explained by the bystander effect. The bystander effect suggests that the more bystanders witness an emergency, the smaller the chance that someone intervenes (Darley & Latané, 1968). In order to prevent situations where the bystander effect plays a part, solutions to the bystander effect should be tested and implemented. This paper will try to conceptualize the bystander effect by using game theory. This will be done by illustrating how the number of people present influences the cost of helping and the helpers payoff and thus his strategy. Therefore, our research question is: ‘How can game theory explain the bystander effect and how can it give insights to possible solutions?’

            This paper will answer this question by first assessing the bystander effect in more detail, then explaining how a social psychological problem can be converted into a game-theoretic problem. Then the bystander effect will be examined through game-theoretic analysis to see if it is possible to mathematically explain this phenomenon. Furthermore, possible solutions of the bystander effect, such as rewards and punishments, will be investigated. I will finish by discussing the limitations and feasibility of using game theory to explain a complex social psychological phenomenon such as the bystander effect.