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Being with a crowd can also make it easy to avoid personal responsibility for taking action. Group inaction conveys the sense to all that the “definition of the situation” is do nothing and don’t get involved.

The Bystander Effect

In the famous 1964 “Kitty Genovese” incident, a young woman named Kitty Genovese was stabbed to death outside her home in Queens, New York. Many of Kitty’s neighbors heard her desperate screams for help, yet no one called the police until  too late. Report of this event shocked the city and the nation, and became the impetus for research on the psychological phenomenon that became known as the “Bystander Effect” by psychologists John Darley and Bibb Latané.

Diffusion of Responsibility

One reason that the bystander effect occurs is  the social influence process known as “diffusion of responsibility”. Through numerous studies, psychologists have found that bystanders are less likely to intervene in emergency situations as the size of the group increases. The presence of others makes one feel less personally responsible for responding to events and each additional person present lowers the chances of anyone helping at all. People tend to assume that someone else will provide the necessary help, especially when there are many others around who could potentially do so.

Looking to Others for Guidance in Ambiguous Situations

A second mechanism behind the bystander effect is the reliance upon others to help interpret ambiguous circumstances. When alone, individuals are responsible for deciding how to respond appropriately to a situation. But when there are others present, we look to them for guidance, especially when an unusual or novel event is occurring, (such as an emergency). Unfortunately, this can cause everyone in the situation to assume that nothing needs to be done, if no one else is doing anything at the moment (an effect referred to as “pluralistic ignorance”).

Rosenthal, A.M. (1964). Thirty-Eight Witnesses: The Kitty Genovese Case. University of California Press.
Darley, J. M. & Latané, B. (1968). Bystander intervention in emergencies: Diffusion of responsibility. Journal of Personality and Social Psychology, 8, 377-383.