Bystander effect refers to the finding that the greater the number of bystanders who witness an emergency, the less likely any one of them is to help. It is the phenomenon that underlies many examples of failing to help strangers in distress: the larger the group a person is in (or thinks he is in), the less likely he is to come to a stranger's assistance. One reason is diffusion of responsibility (no one thinks it is his responsibility to act).
Other /More definition:
Bystander effect refers to the tendency for the presence of other people to inhibit helping. It is the finding that a person is less likely to provide help when there are other bystanders. Moreover, it is the social phenomenon in which individuals are less likely to provide needed help when others are present than when they are alone. It is the tendency for people to help less when they know others are present and capable of helping. The effect was initially thought to be the result of apathy and a selfish unwillingness to get involved, but research suggests a number of cognitive and social processes, including diffusion of responsibility and misinterpretation that help is not needed, contribute to the effect.

Related Articles

Bystander intervention (Bystander effect) at■■■■■■
- Bystander intervention (Bystander effect) : Bystander intervention (Bystander effect ) it is a finding . . . Read More
Diffusion-of-responsibility effect at■■■■■
Diffusion-of-responsibility effect refers to the belief that we don't need to help in an emergency because . . . Read More
Diffusion of responsibility at■■■■■
Diffusion of responsibility: Diffusion of responsibility refers to the phenomenon whereby each bystander's . . . Read More
Free riding at■■■■
Free riding when an individual contributes less to a collective task when he or she believes that other . . . Read More
Compulsions at■■■■
Compulsions refer to repetitive behaviors, such as hand washing, checking, counting or mental acts that . . . Read More
Sucker effect at■■■■
Sucker effect refers to the tendency for individuals to contribute less to a group endeavor when they . . . Read More
Black-sheep effect at■■■■
Black-sheep effect refers to the the tendency for group members to evaluate a disliked ingroup member . . . Read More
Contagion effect at■■■■
Contagion effect refers to the tendency of some people to model or copy Behavior or activity portrayed . . . Read More
Group polarization effect at■■■■
Group polarization effect refers to a tendency for group decisions to be more extreme than the decisions . . . Read More
False consensus effect at■■■■
False consensus effect refers to man's incorrect belief that others agree with him; - - It is The tendency . . . Read More