What Is the Bystander Effect?
The bystander effect occurs when the presence of others discourages an individual from intervening in an emergency situation. Social psychologists Bibb Latané and John Darley popularized the concept following the infamous 1964 Kitty Genovese murder in New York City. As Genovese was stabbed to death outside her apartment, neighbors failed to step in to assist or call the police. Latané and Darley attributed the bystander effect to the perceived diffusion of responsibility (onlookers are less likely to intervene if there are other witnesses who seem likely to do so) and social influence (individuals monitor the behavior of those around them to determine how to act).