A psychological state in which a person loses their sense of identity when joining a group or large crowd, resulting in reduced control over their behavior and individual responsibility. In this state, people become more susceptible to group behavior and may commit actions that are contrary to their habitual personal values and principles, whether positive or negative. Depersonalization occurs as a result of several factors, including large crowds, masking or anonymity, group emotional stimulation, and intense interpersonal interaction. From a psychological point of view, research confirms that impersonality leads to increased impulsivity, aggressive behavior, and intense emotional reactions. It can also encourage participation in immoral or socially unconventional activities, such as violence, vandalism, or even highly voluntary behaviors, such as interacting in positive contexts, such as holidays or social movements. From a sociological perspective, the phenomenon of impersonality demonstrates how groups can influence people’s behavior, both positively and negatively, through a sense of belonging and wholeness. It also emphasizes the ability of groups to stimulate uncontrollable behavior due to a weak sense of individual responsibility, especially in large crowds or in situations that promote anonymity or disguise.