Diffusion of responsibility, also referred to as the "bystander effect," refers to a phenomenon in which the greater number of people present, the less likely an individual is to take action where intervention is required. This phenomenon is commonly observed under two separate scenarios. Someone may witness a crime or a person in distress and take no action to resolve the situation or offer help, assuming that another witness will intervene. An individual may choose not to get involved due to rational and irrational fears. For instance, fear of physical harm, public embarrassment, involvement with police procedures, lost work days and jobs, and other unknown dangers. Diffusion of responsibility can also help explain individuals partaking in illegal or unethical activity against their own moral judgment. These individuals often deny fault, claiming they were merely acting under the orders of a superior.
Many real world situations have been explained using this phenomenon. The case of Kitty Genovese is perhaps one of the most well-known examples where bystanders failed to intervene and prevent or dissolve a crime. The American soldiers involved in the My Lai Massacre during the Vietnam war is an extreme example of people following orders, not questioning authority, and ignoring their own judgments.
Around 3:30am on March 13, 1964, Kitty Genovese was walking home from work where she was a bar manager when she encountered a man walking towards her.  Despite her efforts to run, Winston Moseley caught her and began to attack her. After Mosely stabbed her twice, a man in an apartment above the street called out to "leave that woman alone," causing Moseley to flee into a nearby ally where his car was parked. The man in the apartment above began to defy the bystander effect by taking action in an emergency situation, but unfortunately he did not follow through on his actions by calling for help or helping Kitty himself. After yelling out to Moseley, the man turned out his lights and was not heard again. When Moseley saw this, he returned to Genovese where he continued to attack and stab her until she died.
This murder in Queens, NY would not have received as much attention as it did if the New York Times had not released an article questioning human behavior on the basis that between 35 and 40 neighbors had either heard or seen the attack. It was this article that began to raise concerns of the negative consequences of the bystander effect. The murder and the related article also coined the term Genovese Syndrome as an alternative to the bystander effect.
Black Friday ShoppersEdit
Around two thousand shoppers anxiously waited for the Walmart in Valley Stream, NY to open on Black Friday, November 28, 2008. Six employees were assigned to hold back the enthusiastic mob from the store’s sliding doors. Unfortunately the sliding doors gave way to the power of the crowds, and Wal-Mart employee Jdimypai Damour fell and was trampled by the crowd. Nobody stopped to help move him out of harm’s way and even when help arrived, the mob continued to jostle and ignore the paramedics and officers. Damour was taken to a nearby hospital where he was later pronounced dead.
Due to the large, eager crowd entering the Wal-mart, customers were able to diffuse the responsibility of helping Damour as they assumed another customer, perhaps one more qualified to do so, would provide assistance.
On October 13, 2011 in Foshan, Guangdong province in China, a two-year old girl, Wang Yue, fell into the street where she was hit by two cars. She remained in the road for over five minutes until a woman, Chen Xianmei, came to her rescue. Reports claim that at least 18 people passed by Wang Yue but did not attempt to help as they saw her bleeding and in pain in the middle of the street.
When video and reports of the accident were uploaded to the Internet, many tried to justify the lack of intervention with Chinese culture, but behaviors related to diffusion of responsibility are apparent in most, if not all, cultures around the world.
My Lai MassacreEdit
On March 16, 1968, Second Lieutenant William Calley killed 22 My Lai villagers in what is now known as the Vietnam My Lai Massacre.  This was the mass murder of about 500 unarmed civilians, mostly consisting of women, children, infants, and elderly people in South Vietnam. While 26 United States soldiers were initially charged with criminal offenses for their actions, only Calley was actually convicted.
My Lai was a peaceful, thriving village before the United States Army moved in. It was a heavily mined area where the Viet Cong were deeply entrenched. However, numerous members of the platoon had been killed in the area during the preceding weeks. The agitated troops, under Calley, entered the village for engagement with their elusive enemy. As this mission unfolded, it soon degenerated into the massacre of unarmed civilians.
At one point during the massacre, 70-80 villagers were rounded up by the platoon, forced into a ditch, and killed by Calley himself. Now, Calley testified that he was ordered by Captain Ernest Medina to kill everyone in the village of My Lai. There was enough evidence to convict Calley of murder, and he therefore was sentenced with life in prison. Calley's trial began on November 17, 1970 in which the military prosecution contented that Calley ordered his men to murder unarmed civilians, despite the fact that his men were not under enemy fire. After a 79 hour deliberation, the jury convicted Calley on March 29, 1971 of the premeditated murder of 22 Vietnamese civilians.  Many people were outraged not at Calley's guilty verdict, but that he was the only one within the chain of command who was convicted. Calley was released in 1974, only 3 years after he entered prison, after many appeals.
United States Army helicopter pilot, Hugh Thompson, Jr., is an example of someone who overcame the bystander effect in the midst of bad leadership decisions. As he flew over the My Lai village on March 16, 1968, he noticed a large number of dead civilians on the ground. Thompson and his crew made multiple attempts to radio for help. After no response, Thompson landed his helicopter and confronted Calley- who told Thompson that this did not concern him. After the unsuccessful conversation with Calley, Thompson found a group of 10 civilians hiding in a homemade bomb shelter. He coaxed them out and convinced helicopters to evacuate them. Other helicopters soon began evacuating civilians as well. Thompson even went as far to tell his crew that if the American soldiers tried to harm the cowering villagers, then they should open fire upon the Americans. After returning the civilians to their base, Thompson reported the massacre to his superiors. Thompson was awarded the Distinguished Flying Cross in the aftermath of the My Lai Massacre. However, Thompson refused to accept the medal unless it was also given to his crew mates, Larry Colburn, and, posthumously, Glenn Andreotta.
In 1998, Thompson and one of his crew members returned to the village of My Lai, where they met some of the villagers that they rescued many years ago. They also dedicated a new elementary school to the children of My Lai. The decision that Thompson made so many years ago not only saved lives on that day, but also had lasting effects on the My Lai village for years to come.
Decision Making ProcessEdit
John Darley and Bibb Latane, two psychologists who studied the bystander effect, developed a model of helping which attempted to explain the decision making process a bystander goes through when determining whether to take action. Their model of helping, which is similar to other decision models, contains five steps.
- A bystander must first notice that an event is occurring that may require assistance. Many factors contribute to whether a bystander will notice an event. For example, in an urban environment, a bystander is less likely to notice something out of the ordinary due to stimulus overload.
- After the bystander notices an event, they must interpret the need for help and identify the event as some form of emergency. Sometimes, an emergency will be extremely evident, yet many situations can be ambiguous. Residents in the middle of a large city are used to car alarms, yelling, and other loud noises occurring at night. However, people rarely call 911 or further investigate the sound of a car alarm. Therefore, many bystanders fail to intervene in a situation solely because they fail to interpret the severity and need for help.
- If the situation requires help, the bystander must take personal responsibility for helping. This step is where diffusion of responsibility most comes into play. If the bystander is surrounded by other onlookers, he or she is less likely to take further action. Pluralistic ignorance states that people often look to others to determine what to do without realizing that others are looking at them for the same purpose.
- Once the bystander takes responsibility, he or she must decide upon an appropriate helping response. If the bystander has difficulty determining the what kind of aid is necessary, they are less likely to intervene. Additionally, a bystander may assume that someone else is more capable or better suited to help in the situation, passing off the responsibility to another onlooker. There are two classes of intervention in emergency situations: direct and reportorial. Direct intervention often requires skill, power, or knowledge, and can involve danger. However, a witness may choose to report the situation to someone more qualified to handle the situation such as a police officer or medical personnel.
- Finally, the bystander must take action and implement the chosen response.
Leveraging Diffusion of ResponsibilityEdit
Targeting individuals rather than groups can help leverage diffusion of responsibility. When requesting help, asking someone specifically will likely result in the most useful response. A study completed in 2002 observed the relationship between private email requests and the diffusion of responsibility, anticipating that the the probability of receiving a helpful response is an inverse function of the number of simultaneous addressees. Results of the study showed that there are more responses to emails addressed to a single recipient, that those responses are more helpful, and that they are lengthiest.
It is also important to find a way to make the present situation seem personal. A bystander will most likely have no personal stake (i.e. financial, emotional) in an event that they witness. Thus, a bystanders incentive to help often comes from internally. Respectable ethics and moral judgments can help motivate a bystander to provide or seek appropriate assistance.
- Cherry, Kendra. "What is diffusion of responsibility?" http://psychology.about.com/od/dindex/f/diffusion-of-responsibility.htm. Retrieved April 18, 2012.
- Darley, John M., & Latane, Bibb (1968). "Bystander intervention in emergencies: Diffusion of responsibility." Journal of Personality and Social Psychology, 8(4), 377-383. http://psycnet.apa.org/journals/psp/8/4p1/377.pdf. Retrieved April 18, 2012.
- Milgram, N., & Hollander, P. (1964). "Murder they heard." Nation, 198, 602-604.
- Reviving Kitty Genovese Case, and Its Passions. (1995, July 25). http://www.nytimes.com/1995/07/25/nyregion/reviving-kitty-genovese-case-and-its-passions.html?pagewanted=all&src=pm
- Black Friday turns tragic for Wal-Mart. (2008, November 28). http://money.cnn.com/2008/11/28/news/economy/blackfriday_walmart/index.htm
- Chinese Toddler’s Hit and Run: Mother Praises Rescuer. (2011, October 11). http://www.pbs.org/wgbh/amex/vietnam/trenches/my_lai.html
- Toddler incident in China shows 'volunteer's dilemma'. (2011, October 18). http://www.cnn.com/2011/10/18/opinion/kreuger-china-incident/index.html
- The My Lai Massacre. (2005, March 25). http://www.pbs.org/wgbh/amex/vietnam/trenches/my_lai.html
- William Calley. (2007, March 29). http://www.freerepublic.com/focus/f-news/1808937/posts
- About the Hugh Thompson Foundation. (n.d.). http://www.designaire.com/HughThompson/about.htm
- Darley, J.M., Latané, B. (1968a). Group Inhibition of Bystander Intervention in Emergencies. Journal of Personality and Social Psychology, 10(3), 215-221.
- Schroeder, D. A., Penner, L. A., Dovidio, J. F., & Piliavin, J. A. (1995). The psychology of helping and altruism. New York: McGraw-Hill, Inc.
- Kafka, P. (2009, May 6). The psychology of helping: Understanding how crimes are witnessed and not reported or stopped.
- Lickerman, A. (2010, June 14). The diffusion of responsibility: Why assigning responsibility to groups doesn't work. http://www.psychologytoday.com/blog/happiness-in-world/201006/the-diffusion-responsibility. Retrieved April 29, 2012.
- Barron, Greg & Yechiam, Eldad (2002, September). "Private e-mail requests and the diffusion of responsibility." Computers in Human Behavior, 18(5), 507-520. http://www.sciencedirect.com/science/article/pii/S0747563202000079. Retrieved April 18, 2012.