Diffusion of responsibility is a sociopsychological phenomenon whereby a person is less likely to take responsibility for action or inaction when others are present. Considered a form of attribution, the individual assumes that others either are responsible for taking action or have already done so. The phenomenon tends to occur in groups of people above a certain critical size and when responsibility is not explicitly assigned. It rarely occurs when the person is alone and diffusion increases with groups of three or more.
Diffusion of responsibility occurs in large group settings and under both prosocial and antisocial conditions. In prosocial situations, individuals' willingness to intervene or assist someone in need is inhibited by the presence of other people. The individual is under the belief that other people present will or should intervene. Thus, the individual does not perceive it as his or her responsibility to take action. This will not happen if the individual believes that they are the only one aware of the situation. If a bystander is deciding how to help, they may abstain from doing so if they believe that they lack the competence to be of aid. Individuals may become reluctant to provide help for fear of how observers will view them. The Murder of Kitty Genovese is the classic case study for diffusion of responsibility in a prosocial situation. It has been demonstrated that the likelihood of a person offering help decreases as the number of observers present increases. This is known as the bystander effect. In addition, diffusion of responsibility is more likely to occur under conditions of anonymity. In prosocial situations, individuals are less likely to intervene when they do not know the victim personally. Instead, they believe that someone who has a relationship with the victim will assist. In antisocial situations, negative behaviors are more likely to be carried out when the person is in a group of similarly motivated individuals. The behavior is driven by the deindividuating effects of group membership and the diffusion of feelings of personal responsibility for the consequences. As part of this process, individuals become less self-aware and feel an increased sense of anonymity. As a result, they are less likely to feel responsible for any antisocial behavior performed by their group. Diffusion of responsibility is also a causal factor governing much crowd behavior, as well as risk-taking in groups.
Diffusion of responsibility can manifest itself:
Social psychological experiments have demonstrated that individuals' failure to assist others in emergencies is not due to apathy or indifference, but rather to the presence of other people. This is explained by both bystander effect and diffusion of responsibility. In 1968 and a series of experiments that followed, John Darley and Bibb Latané demonstrated that an individual's choice to help or intervene when there is an emergency depends on the number of bystanders. Group size significantly influenced the likelihood of helping behavior in a staged emergency: 85% of participants responded with intervention when alone, 62% of participants took action when with one other person, and only 31% did when there were four other bystanders. Other studies have replicated the phenomenon, including reports from real emergencies such as calling an ambulance for overdose patients and offering CPR after cardiac arrest.
In ambiguous situations, the individual's appraisal of the situation and subsequent action or inaction largely depends on the reactions of other people. Other bystanders' interpretation of an emergency influences perception of the incident and helping behavior. In one study, diffusion of responsibility does not occur if another bystander is perceived as being unable to help.
Group psychology can also influence behavior positively; in the event that one bystander takes responsibility for the situation and takes specific action, other bystanders are more likely to follow course. This is a positive example of the usually-pejorative herd mentality. Thus, the presence of bystanders affects individual helping behavior by processes of social influence and diffusion of responsibility.
Researchers have identified five decision stages that a bystander encounters:
In risk-taking literature, diffusion of responsibility occurs when individual members of a group feel less personal responsibility for potential failure in the pursuit of risky options than if acting alone. Such risky shift is a stable phenomenon that has been shown in experiments involving group discussion and consensus. For example, a study using risks and payoffs based on monetary gain and loss for problem-solving performance found a greater percentage of shift—hence, increased risk taking in group decision making.
Other research suggests that risky shifts can also be attributed to group polarization, majority rules, interpersonal comparisons, informational influence, and familiarization. Like diffusion of responsibility in emergency situations, the larger the size of the group during conditions of discussion and information exchange, the greater the risky shift.
The diffusion of responsibility for alleged war crimes during World War II was famously used as a legal defense by many of the Nazis being tried at Nuremberg. A similar defense was mounted by the defendants accused in the My Lai massacre.