What is one reason for the bystander effect?

The bystander effect is primarily influenced by the diffusion of responsibility. This concept suggests that when multiple individuals are present in an emergency or critical situation, the sense of personal responsibility felt by each individual decreases. As a result, individuals may be less likely to take action or help, believing that someone else in the group will. This phenomenon is commonly observed in social psychology and illustrates how the presence of others can lead to inaction, as everyone assumes someone else will intervene.

In contrast, other concepts such as overconfidence bias, lack of interest in the situation, and groupthink do not directly explain why individuals might fail to act when confronted with an emergency. Overconfidence bias relates to an individual's assessment of their own skills or knowledge, lack of interest indicates apathy toward a situation, and groupthink refers to a mode of thinking that occurs within a cohesive group, often leading to poor decision-making. However, none of these concepts capture the essence of how shared responsibility among a group can lead to inaction, which is central to understanding the bystander effect.