The effect of the presence of others on an individual's perception of and response to a situation.
The term bystander effect, or bystander apathy, was first employed by psychologists in the early 1960s. The 1964 murder of New Yorker Kitty Genovese provides an illustration of this phenomenon. Genovese, who was being savagely attacked outside her apartment building, screamed for help for over 30 minutes. Although 40 neighbors heard Genovese's desperate cries, no one came to her aid or even called the police. Researchers have explained several components of the bystander effect. First, witnesses must perceive the situation as an emergency. When others are present, not taking action or behaving as if nothing were wrong, all observers tend to view the situation as a nonemergency. Psychologists describe this as pluralistic ignorance, in which the behavior of the group causes each individual to be lulled into inaction. In the case of Genovese's murder, her neighbors were not hearing her cries for help as a group. Each person, isolated in his or her own apartment, heard the disturbance and had no way of knowing the reactions of others who were hearing Genovese's screams. However, each person could believe that someone else was taking action, and therefore the responsibility for response fell to that other person. Psychologists call this reaction diffusion of responsibility.
Experiments have been developed to demonstrate the components of the bystander effect. In one experiment designed to test the power of pluralistic ignorance, male subjects were given appointments for an interview. As they wait in an outer room, smoke begins to pour through a ventilation duct. Researchers observed the subjects through a one-way mirror for three minutes. Seventy-five percent of the subjects who were alone in the waiting room reported the smoke within two minutes, while 13 percent of those tested in groups reported the smoke. Those who did not report the smoke explained that, since others in the room did not seem to be concerned, the smoke must have been air conditioning vapors or steam. This experiment illustrates that bystanders can contribute significantly to an individual's interpretation of a situation.
Latani, Bibb. The Unresponsive Bystander: Why Doesn't He Help? New York: Appleton-Century Crofts, 1970.
Palma, Giuseppe. Apathy and Participation: Mass Politics in Western Societies. New York: Free Press, 1970.