Research has shown that, even in an emergency, a bystander is less likely to extend help when he or she is in the real or imagined presence of others than when he or she is alone. In the late 1960s, John M. Darley and Bibb Latané (1968) initiated an extensive research program on this so-called “bystander effect.” In their seminal article, they found that any person who was the sole bystander helped, but only 62% of the participants intervened when they were part of a larger group of five bystanders. The starting point for research on the bystander effect was the brutal rape-murder of Catherine “Kitty” Genovese in 1964. Introduction. When an emergency situation occurs, observers are more likely to take action if there are few or no other witnesses. The bystander effect occurs when the presence of others discourages an individual from intervening in an emergency situation. The American Bystander I want to be like the man on the subway who told the operator about the woman's seizure, because as soon as he did, people followed suit and offered help. In the late 1960s, John M. Darley and Bibb Latané (1968) initiated an extensive research program on this so-called “bystander effect.” In their seminal article, they found that any person who was the sole bystander helped, but only 62% of the participants intervened when they were part of a larger group of five bystanders. Abstract This article provides a historical perspective on the bystander effect, a social phenomenon that Darley and Latané first studied experimentally in 1968. We have the power to choose whether to justify passivity or actively decide to do the right thing, and as a society I believe we ought to break free from our psychological tendency to just stand by. The term bystander effect refers to the phenomenon in which the greater the number of people present, the less likely people are to help a person in distress. Bystander effect, the inhibiting influence of the presence of others on a person’s willingness to help someone in need. Critical events that took place prior to the study of the bystander effect are discussed.