Imagine yourself in the following situation: You sign up for a psychology experiment, and on a specified date you and seven others whom you think are also subjects arrive and are seated at a table in a small room. You don't know it at the time, but the others are actually associates of the experimenter, and their behavior has been carefully scripted. You're the only real subject.
The experimenter arrives and tells you that the study in which you are about to participate concerns people's visual judgments. She places two cards before you. The card on the left contains one vertical line. The card on the right displays three lines of varying length.
The experimenter asks all of you, one at a time, to choose which of the three lines on the right card matches the length of the line on the left card. The task is repeated several times with different cards. On some occasions the other "subjects" unanimously choose the wrong line. It is clear to you that they are wrong, but they have all given the same answer.
What would you do? Would you go along with the majority opinion, or would you "stick to your guns" and trust your own eyes?
In 1951 social psychologist Solomon Asch devised this experiment to examine the extent to which pressure from other people could affect one's perceptions. In total, about one third of the subjects who were placed in this situation went along with the clearly erroneous majority.
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. When an emergency situation occurs, observers are more likely to take action if there are few or no other witnesses.
In a series of classic study, researchers Bibb Latane and John Darley found that the amount of time it takes the participant to take action and seek help varies depending on how many other observers are in the room. In one experiment, subjects were placed in one of three treatment conditions: alone in a room, with two other participants or with two confederates who pretended to be normal participants.
As the participants sat filling out questionnaires, smoke began to fill the room. When participants were alone, 75% reported the smoke to the experimenters. In contrast, just 38% of participants in a room with two other people reported the smoke. In the final group, the two confederates in the experiment noted the smoke and then ignored it, which resulted in only 10% of the participants reporting the smoke.
Example of the Bystander Effect
The most frequently cited example of the bystander effect in introductory psychology textbooks is the brutal murder of a young woman named Catherine "Kitty" Genovese. On Friday, March 13, 1964, 28-year-old Genovese was returning home from work. As she approached her apartment entrance, she was attacked and stabbed by a man later identified as Winston Moseley.
Despite Genovese’s repeated cries for help, none of the dozen or so people in the nearby apartment building who heard her cries called police for help. The attack first began at 3:20 AM, but it was not until 3:50 AM that someone first contacted police.
Initially reported in a 1964 New York Times article, the article sensationalized the case, despite a number of factual inaccuracies. While frequently cited in psychology textbooks, an article in the September 2007 issue of American Psychologist concluded that the story is largely misrepresented mostly due to the inaccuracies repeatedly published in newspaper articles and textbooks.
Explanations for the Bystander Effect
There are two major factors that contribute to the bystander effect. First, the presence of other people creates a diffusion of responsibility. Because there are other observers, individuals do not feel as much pressure to take action, since the responsibility to take action is thought to be shared among all of those present.
The second reason is the need to behave in correct and socially acceptable ways. When other observers fail to react, individuals often take this as a signal that a response is not needed or not appropriate. Other researchers have found that onlookers are less likely to intervene if the situation is ambiguous. In the case of Kitty Genovese, many of the 38 witnesses reported that they believed that they were witnessing a "lover’s quarrel," and did not realize that the young woman was actually being murdered.
October 9, 2008 lecture by Philip Zimbardo during the 2008 Reunion Homecoming Classes Without Quizzes program. Why do good people turn evil? In what sense are evil and heroism comparable? How could the little old Stanford prison experiment reveal parallels and insights about the abuses by military guards at Abu Ghraib?
Philip Zimbardo, professor of psychology, emeritus, is internationally recognized as a leading "voice and face of contemporary psychology" through his widely seen PBS-TV series, Discovering Psychology, his media appearances, best-selling trade books on shyness, and his classic research, The Stanford Prison Experiment.
Journey From the Psychology of Evil to the Psychology of Heroism
The experimenter asks all of you, one at a time, to choose which of the three lines on the right card matches the length of the line on the left card. The task is repeated several times with different cards. On some occasions the other "subjects" unanimously choose the wrong line. It is clear to you that they are wrong, but they have all given the same answer.
