Psi man mascot

Bystander Apathy
(The Bystander Effect)

A few years before his obedience research, Stanley Milgram and his colleagues were contemplating a different sort of study. "The idea started in the summer of 1960," Milgram later recalled.

Some friends and I decided to improvise some street-theater scenes. We stopped at restaurants along the Massachusetts Turnpike and enacted common human situations: irate wife discovers her husband with another woman and rages at him in an incomprehensible mock-foreign language.

What impressed me was that despite the extreme emotion in the encounter, onlookers conspicuously avoided involvement, even when the husband shook and slapped his 'wife' in retaliation. (Milgram, 1992, Preface,

Milgram never pursued the idea. He was just beginning to teach at Yale, working on the obedience experiments, and did not have the time to run another series of experiments simultaneously.

What research did Milgram contemplate that resembled later bystander effect experiments?

Within a few years, reality caught up with his research idea. A horrible crime in New York City gained widespread publicity.

The Genovese Murder

The issue of bystander apathy (also known as the bystander effect) was raised by the murder on March 13, 1964, of a young woman named Catherine (Kitty) Genovese. The original news reports of this crime in the New York Times started with the line "For more than half an hour 38 respectable, law-abiding citizens in Queens watched a killer stalk and stab a woman in three separate attacks in Kew Gardens."

Twenty years later, on the anniversary of the crime, the New York Times propagated the original version once more. This time they wrote, "For more than half an hour that night, Miss Genovese's killer stalked and stabbed her, again and again, as 38 of her neighbors silently turned away from her cries." (Dowd, 1984)

Both versions were inaccurate, and researchers finally started to become aware of this 40 years after the crime. By 2016, the original 1964 article, available on the web from the New York Times archives, had a new postscript added to it. The postscript read:

Editors' Note: October 12, 2016: Later reporting by The Times and others has called into question significant elements of this account.

Here is part of the 1964 article. You can see why it was upsetting to many people.

She got as far as a street light in front of a bookstore before the man grabbed her. she screamed. Lights went on in the 10-story apartment house at 82-67. Austin Street, which faces the bookstore. Windows slid open and voices punctured the early-morning stillness.

Miss Genovese screamed: "Oh, my God, he stabbed me! Please help me! Please help me!"

From one of the upper windows in the apartment house, a man called down: "Let that girl alone!"

The assailant looked up at him, shrugged and walked down Austin Street toward a white sedan parked a short distance away. Miss Genovese struggled to her feet.

Lights went out. The killer returned to Miss Genovese, now trying to make her way around the side of the building by the parking lot to get to her apartment. The assailant stabbed her again.

"I'm dying!" she shrieked. "I'm dying!" She shrieked. "I'm dying!"

A city bus passed.

Windows were opened again, and lights went on in many apartments. The assailant got into his car and drove away. Miss Genovese staggered to her feet... The assailant returned...

It was 3:50 by the time the police received their first call, from a man who was a neighbor of Miss Genovese. In two minutes they were at the scene. The neighbor, a 70-year-old woman and another woman were the only persons on the street. Nobody else came forward.

The man explained that he had called the police after much celebration. He had phoned a friend in Nassau County for advice and then he had crossed the roof of the building to the apartment of the elderly woman to get her to make the call.

"I didn't want to get involved," he sheepishly told the police. (Gansberg, 1964)

The killer, named Winston Moseley, later confessed to the Genovese killing. He said he had been cruising the city at 3 a.m., planning "to rape and to rob and to kill a girl." He also confessed to two other recent murders in the area. (He died in prison at age 81, in 2016.)

How did the initial 20+ years of reporting on the Genovese murder create a misleading impression?

A historian and lawyer, Joseph De May, Jr., made a "meticulous analysis" of court transcripts and legal documents associ­ated with the case. He found numerous inaccuracies in the New York Times report.

De May also notes: "Much has been made of the fact that the first attack occurred near a street light... However, the street light there today (and in 1999) is not the one that was there the night Kitty was attacked. The new one is brighter and covers a wider zone...

Moseley testified that he did not worry about being identified when he returned to continue his attack on Kitty because: '... it was late at night and I was pretty sure that nobody could see that well out of the window.'"

De May continues: "The dim lighting is an important factor here. Even though witnesses could have seen the figures of Kitty and her attacker, smaller telltale details such as the use of a knife or the presence of blood would have been harder to detect. ...One of the two witnesses we know of who saw the first attack thought she was seeing Kitty beaten rather than stabbed.

De May pointed out most of the resi­dents of the building were elderly, and "lights going on" after Genovese screamed meant they were going to their windows. However, the stabbing had already occurred by that time, so they could not have witnessed it.

Five different witnesses testified at Moseley's trial, and not one of them saw anything more than Moseley kneeling or bending over Genovese. Nobody saw any violence.

Why was the lack of response from residents near the Genovese murder not quite as amazing as it seemed initially?

Manning, Levine, and Collins (2007) gave De May's findings a wide audience in an American Psychologist article. They also emphasized the inaccurate reporting of the crime did not invalidate the "elegant, inventive, and extremely persuasive" research on bystander apathy. Over 1,000 articles and books were written about bystander effects after the attack on Genovese.

The Research Tradition

A bystander effect occurs when witness­es fail to help a person in distress. Psychologists Bibb Latané and John Darley were inspired to study it by the Genovese murder.

Darley and Latané (1968) hypothesized that bystander apathy was caused by a dilution of the individual's sense of responsibility in a larger group of people. This diffusion of responsibility theory was tested in a laboratory experiment.

In some conditions, the students were told they were one of two subjects. In other conditions, they were told they were one of six subjects. After the experiment started, the subjects thought they over­heard a fellow participant having an epileptic seizure.

In the six-person condition, 31% of the subjects responded to calls for help. In the two-person condition, 85% of the subjects responded.

What experiments supported the diffusion of responsibility theory?

Similarly, Latané and Rodin (1969) staged an experiment at Columbia University. They had students meet an experimenter, then divided them up to fill out questionnaires. Each student was assigned to a cubicle.

Suddenly there was a crash and scream from one of the cubicles and a girl student's voice called out, "Oh My God, my foot! I can't move it! ankle...I can't get this thing off me!" Of course, the "accident" was faked, but the subjects presumably thought it was real.

When subjects were by themselves in a cubicle, 70% responded. When subjects were grouped in pairs, only 40% responded.

These findings were consistent with the diffusion of responsibility theory. The same effect occurred whether people thought they were in a larger group or actually were in a larger group.

Both of these studies were artificial. Subjects may have been suspicious that the emergency was faked. To test the diffusion of responsibility theory in a naturalistic (real-life) setting, Latané and Darley (1969) set up a fake robbery in a liquor store. The robbers were two young men who entered the store and asked the clerk about an expensive imported beer.

The clerk (who, like the two men, was a confederate of the experi­menter) said he would check in the back room. He left the front of the store. The two men grabbed a case of beer, saying, "They won't miss this," and went out the door.

The point of the experiment was to see if other customers (who thought the robbery was genuine) would mention it to the clerk when he came back to the front of the store. When customers were alone, 65% reported it.

When customers were in a group of two, 56% reported it. This effect was quite a bit smaller than the diffusion of respon­sibility effect in the laboratory studies, although it was in the predicted direction. (Latané and Darley, 1969)

What personal characteristics of the victim were found to influence bystander apathy?

Personal characteristics of the victim were found to influence bystander apathy. Piliavin, Rodin, and Piliavin (1969) con­ducted a study in naturalistic conditions. They arranged for a confederate of the experimenter to collapse in a New York subway.

In one version of the experiment, the man was dressed like a bum, sported a three-day growth of beard, and smelled of alcohol. Most people failed to help him as he collapsed into a heap on the floor of the subway car. When a well-dressed businessman type was used in the same experiment, more passengers respond­ed with offers of help.

Other studies showed that previous personal contact encouraged helping behavior. A brief period of conversation with a "victim" made subjects more likely to respond during a pretended emergency.

Darley and Batson (1973) asked semi­nary students (students studying to become preachers or ministers) to rehearse a speech in one room, then go to another room to deliver the speech to a waiting group. On the way to the second room, each student passed a person slumped in a doorway.

What factor made seminary students ignore a man slumped in a doorway?

If the experimenters made the students think they were late for their speech, only 10% helped the stranger. If they students thought they were early for the speech and had time to spare, nearly half of them helped out. Convenience, therefore, also influenced the bystander effect.

Dangerous crime situations are prob­ably the most likely to provoke bystand­er non-involvement, for obvious reasons. Huston, Ruggiero, Conner, and Geis (1981) studied 32 individuals who intervened in dangerous crimes.

The responders were interviewed at length and compared to a group of non-interveners matched for age, sex, education, and ethnic background. Those who intervened "were more likely to describe themselves as physically strong, aggressive, emotional, and principled." They tended to be taller, heavier, and better trained than non-interveners.

"In spite of an intensive search for personality differences between the two groups, none were found." The researchers concluded that "crime interveners are not prompted to action by notably strong humani­tarian purpose...but rather act out of a sense of capability founded on training experiences and rooted in their personal strength."

Who was most likely to intervene heroically in real-life crime situations?

Eventually, the frequent occurrence of experiments involving fake emergen­cies led to greater suspicion among subjects. Students read about fake-emergency experiments in psychology classes. When it was time for them to serve as subjects in a psychological experiment, they were "wise" to the deception.

Kelman (1967) warned that social psychology experiments involving deception could backfire if subjects became suspicious every time they entered a psychological laboratory. MacCoun and Kerr (1987) said that Kelman's prediction came true at their school.

What was Kelman's warning, and how did it come true, 20 years later?

A subject had a real seizure during an experiment. Several other subjects were present, but only one (a lifeguard) quickly helped. The others were suspicious that this seizure was being faked for the experiment.

Hortensius and Gelder (2014) reported a neural perspective on the bystander effect. They made fMRI recordings of the left pre- and postcentral gyri: areas involving in "automatic action preparation."

What did Hortensius and Gelder (2014) find, and what is a possible implication?

While participants were doing a color-naming task in the fMRI machines, they "witnessed an emergency." The amount of activation depended on how many bystanders were present.

This implies that bystander effects are the result of quick and automatic processing, what Kahneman called the fast processing system. That quick reaction must be overridden by slower, conscious processing, if a person is to intervene in a crowded situation.

Bystander Intervention

As generations of students learned about bystander effects, institutions introduced rules and recommend­ations to encour­age bystander intervention. Bystanders were urged to report classroom and online bullying, date rape, and overt sexism or racism on the job.

Bystander intervention has been proposed as part of the solution for alcohol poisoning (Megehee, Strick, and Woodside, 2012). In several well publicized cases, students uncon­scious from alcohol poisoning were kept away from medical care until it was too late.

When are bystanders urged to intervene in modern programs?

After a series of school shooting in the 2000s, bystander intervention was suggested as a necessary part of the response. Bystanders were defined as "parents, teachers, and other school staff as well as youths and those who have information about potential violence as well as those who witness its occurrence." (Stueve et al., 2006)

This tactic could be troublesome, as Swan (2015) pointed out. If intervention is required as a matter of policy or law, a person injured as a result of inter­vention might sue the institution.

Consequently, policies recommending bystander intervention usually urge intervention but do not require it. Also, they suggest reporting a crime, not physically intervening to stop it. An exception is the Military Academy and Air Force of the U.S., which compels reporting of (and presum­ably interven­tion in) sexual assault.

What legal reality limits mandatory bystander intervention?

When intervention means reporting or contacting the authorities, fewer legal complications arise. Many public health programs and school educational programs have encouraged bystander intervention of this sort.

Bystander intervention is encouraged in the U.S. for preventing child abuse. In some states it is mandatory. For exam­ple, Texas law says if a person suspects that a child is being abused or neglected, it must be reported. [Texas Family Code Section 261.101 (a)]

Schools started similar policies for incidents of bullying. Polanin, Espelage, and Pigott (2012) did a meta-analysis of school bullying prevention programs and found they increased bystander inter­ventions. "Evidence from 12 school-based programs, involving 12,874 students, indicated that overall the programs were successful."


Darley, J. M. & Batson, C. D. (1973) From Jerusalem to Jericho: A study of situational and dispositional variables in helping behavior. Journal of Personality and Social Psychology, 27, 100-108.

Darley, J. M. & Latané, B. (1968) Bystander intervention in emergen­cies: Diffusion of responsibility. Journal of Personality and Social Psychology, 8, 377-383.

De May, J., Jr. (2006). Kitty Genovese: The popular account is mostly wrong. Retrieved from:

Dowd, M. (1984, March 12) The night that 38 stood by as a life was lost. New York Times. Retrieved from:

Gansberg, M. (1964, March 27) 37 who saw murder didn't call the police. New York Times. Retrieved from:

Hortensius, R. & Gelder, B. D. (2014). The neural basis of the bystander effect. Neuroimage, 93, 53-58.

Huston, T. L., Ruggiero, M., Conner, R., & Geis, G. (1981) Bystander intervention into crime: A study based on naturally-occurring episodes. Social Psychology Quarterly, 44, 14-23.

Kelman H.C. (1967). Human use of human subjects: The problem of deception in social psychological experiments. Psychological Bulletin, 67, 1-11.

Latané, B., & Darley, J.M (1969). Bystander "apathy." American Scientist, 57, 244-268.

Latané, B., Nida, S. (1981). Ten years of research on group size and helping. Psychological Bulletin, 89, 308-324.

Latané, B., Rodin, J. (1969) A lady in distress: Inhibiting effects of friends and strangers on bystander intervention. Journal of Experimental Social Psychology, 5, 189-202.

Manning, R., Levine, M., & Collins, A. (2007). The Kitty Genovese murder and the social psychology of helping: The parable of the 38 witnesses. American Psychologist, 62, 555-562.

Megehee, C. M., Strick, S. K., & Woodside, A. G. (2012) Overcoming bystander apathy and non-intervection in alcohol-poisoning emergency situations. International Journal of Business and Economics, 11, 93-103.

Milgram, S. (1992). The individual in a social world: Issues and experiments, 2nd edition. Edited by J. Sabini & M. Silver. New York: McGraw-Hill.

Piliavin, I. M., Rodin, J. A. & Piliavin, J. (1969) Good Samaritanism: An underground phenomenon? Journal of Personality and Social Psychology, 13, 289-299.

Polanin, J. R., Espelage, D. L., & Pigott, T. D. (2012). A meta-analysis of school-based bullying prevention programs' effects on bystander intervention behavior. School Psychology Review, 41, 47-65.

Stueve, A., Dash, K., O'Donnell, L., Tehranifar, P., Wilson-Simmons, R., Slaby, R. G. & Link, B.G. (2006) Rethinking the bystander role in school violence prevention. Health Promotion Practice, 7, 117-124. doi:10.1177/1524839905278454

Write to Dr. Dewey at

Don't see what you need? Psych Web has over 1,000 pages, so it may be elsewhere on the site. Do a site-specific Google search using the box below.