The theory was first proposed in 1964 after the murder of Kitty Genovese, in which a newspaper had reported (albeit erroneously) that 38 bystanders saw or heard the attack without coming to her assistance or calling the police.
Recent research has focused on "real world" events captured on security cameras, and the coherency and robustness of the effect has come under question.
[1] More recent studies also show that this effect can generalize to workplace settings, where subordinates often refrain from informing managers regarding ideas, concerns, and opinions.
[2][3] The bystander effect was first demonstrated and popularized in the laboratory by social psychologists John M. Darley and Bibb Latané in 1968 after they became interested in the topic following the murder of Kitty Genovese in 1964.
[7] Philpot et al. (2019) examined over 200 sets of real-life surveillance video recordings from the United Kingdom, the Netherlands, and South Africa to answer "the most pressing question for actual public victims": whether help would be forthcoming at all.
Additional research by Faul, Mark, et al., using data collected by EMS officials when responding to an emergency, indicated that the response of bystanders was correlated with the health severity of the situation.
[10] Similarly, interpretations of the context played an important role in people's reactions to a man and woman fighting in the street.
An alternative explanation has been proposed by Stanley Milgram, who hypothesized that the bystanders' callous behavior was caused by the strategies they had adopted in daily life to cope with information overload.
Recent research has considered the role of similarity, and more specifically, shared group membership, in encouraging bystander intervention.
However, when their shared identity as football fans was made salient, supporters of both teams were likely to be helped, significantly more so than a person wearing a plain shirt.
They also found that when gender identity is salient, group size encouraged intervention when bystanders and victims shared social category membership.
[20] In discussing the case of Wang Yue and a later incident in China, in which CCTV footage from a Shanghai subway showed passengers fleeing from a foreigner who fainted, UCLA anthropologist Yunxiang Yan said that the reactions can be explained not only by previous reports of scamming from older people for helping, but also by historical cultural differences in Chinese agrarian society, in which there was a stark contrast between how individuals associated with ingroup and outgroup members, saying, "How to treat strangers nicely is one of the biggest challenges in contemporary Chinese society...The prevailing ethical system in traditional China is based on close-knit community ties, kinship ties."
The ombuds practitioners' study suggests that what bystanders will do in real situations is actually very complex, reflecting views of the context and their managers (and relevant organizational structures if any) and also many personal reasons.
[28] In a further study, Thornberg concluded that there are seven stages of moral deliberation as a bystander in bystander situations among the Swedish schoolchildren he observed and interviewed: (a) noticing that something is wrong, i.e., children pay selective attention to their environment, and sometimes they do not tune in on a distressed peer if they are in a hurry or their view is obstructed, (b) interpreting a need for help—sometimes children think others are just playing rather than actually in distress or they display pluralistic ignorance, (c) feeling empathy, i.e., having tuned in on a situation and concluded that help is needed, children might feel sorry for an injured peer, or angry about unwarranted aggression (empathic anger), (d) processing the school's moral frames—Thornberg identified five contextual ingredients influencing children's behavior in bystander situations (the definition of a good student, tribe caring, gender stereotypes, and social-hierarchy-dependent morality), (e) scanning for social status and relations, i.e., students were less likely to intervene if they did not define themselves as friends of the victim or belonging to the same significant social category as the victim, or if there were high-status students present or involved as aggressors—conversely, lower-status children were more likely to intervene if only a few other low-status children were around, (f) condensing motives for action, such as considering a number of factors such as possible benefits and costs, and (g) acting, i.e., all of the above coalesced into a decision to intervene or not.
The South African courts began using the testimony of expert social psychologists to define what extenuating circumstances would mean in the justice system.
In the case of S. vs. Sibisi and Others (1989) eight members of the South African Railways and Harbours Union were involved in the murder of four workers who chose not to join in the SARHWU strike.
Fraser and Colman stated that bystander apathy, deindividuation, conformity and group polarization were extenuating factors in the killing of the four strike breakers.
On March 13, 1964, 28-year-old bartender Catherine "Kitty" Genovese was stabbed, sexually assaulted, and murdered while walking home from work at 3 a.m. in Queens, New York.
According to a sensationalized article in The New York Times, 38 witnesses watched the stabbings but did not intervene or even call the police until after the attacker fled and Genovese had died.
[41] In 2016, The New York Times called its own reporting "flawed", stating that the original story "grossly exaggerated the number of witnesses and what they had perceived".
[43] It was reported that she was treated politely and drank brandy with the group before the assault took place, which lasted two and a half hours before a young woman notified the police.
[45][46][47] She was hospitalised for scrapes and bruises all over her face and body, and later sustained scars from cigarette burns on her back, as well as hips that regularly pop out of place.
[50][51][52] On October 13, 2021, a passenger was sexually harassed and eventually raped by another rider on a SEPTA train in Philadelphia, with several bystanders in the area purportedly witnessing the incident, even allegedly recording the assault on their phones, and failing to alert authorities or stop the assault until one off-duty employee called 911 after boarding the train and noticing the attack.
[53] After the initial 911 call, a SEPTA officer boarded the train when it arrived at the 69th Street Transportation Center, arresting the suspect after pulling him off the victim.
[54] This assault gained international attention for the passengers' apparent lack of action,[55] though some scholars argued that the bystanders simply did not know what to do in that instance.
[56] According to SEPTA general manager Leslie Richards, the arrest occurred 3 minutes after the initial 911 call, which happened after the victim had been harassed for more than half an hour.
The organization eventually released a statement, saying "There were other people on the train who witnessed this horrific act, and it may have been stopped sooner if a rider called 911.
Subsequently, Gaiyathiri was sentenced to 30 years' imprisonment in June 2021 for a lower charge of culpable homicide not amounting to murder.
Piang's case also demonstrated chilling similarities and comparisons to Kitty Genovese's murder and the existence of the bystander effect, as it was discovered that during the regular health-checks at the hospital and the maid agency, there were people who suspected that Piang may have been abused but Gaiyathiri and her family denied them; no police report was made in relation to these suspected signs of maid abuse.
[65][66] In 2019, a large international cultural anthropology study analyzed 219 street disputes and confrontations that were recorded by security cameras in three cities in different countries: Lancaster, Amsterdam, and Cape Town.