What is the phenomenon called where individuals in a group feel less personal responsibility to act?

The phenomenon where individuals in a group feel less personal responsibility to act is identified as diffusion of responsibility. This occurs because when people are in a group, they tend to assume that someone else will take action, which leads to a decreased sense of individual accountability. This effect is often observed in emergency situations where bystanders may be present; each person might look around and think that someone else will help, resulting in no one taking action.

In contrast, groupthink refers to a situation where the desire for harmony or conformity within a group leads to irrational or dysfunctional decision-making. Social loafing describes the tendency of individuals to put forth less effort when they are part of a group compared to when they work alone. Conformity involves changing one's behavior or beliefs to match those of the group. While all these concepts relate to group dynamics, diffusion of responsibility specifically highlights the impact of group presence on personal accountability.