What is the bystander effect?

The bystander effect refers to a social psychological phenomenon where individuals are less likely to offer help to a victim when other people are present. This effect is primarily attributed to the diffusion of responsibility, where individuals assume that someone else will take action, leading to a decreased likelihood of any single person intervening. In emergency situations, the presence of others can lead to hesitation because individuals may look to others for cues or decide that since no one else is helping, there is no need for them to help either.

In contrast, the other options suggest trends of helping behavior that do not align with the bystander effect. Helping when alone or in groups typically describes the opposite dynamic, where either solitude or group action promotes intervention rather than hindrance. Moreover, an increase in prosocial behavior in crowded situations doesn't capture the essence of the bystander effect, which highlights how crowded situations can actually lead to decreased helping behavior due to the presence of multiple observers.