Mob mentality, or "crowd psychology", "group processes", "groupthink", or in sociology "collective behaviour" or "group behaviour", "mob rule", is a very interesting study within human psychology. The study of this area started around the time of the Kitty Genovese case, where a woman in NYC was brutally raped and stabbed to death in view of 38 witnesses. Psychologists became quite interested in the human dynamics of the case that could cause this apparent "callousness" to happen, and it later became known as the "bystander effect".
Crowd psychology covers a wide range of phenomena, and there are several theories, but the Emergent-norm theory is widely supported, there are other theories as well:
$this->bbcode_second_pass_quote('', 'R')alph Turner and Lewis Killian developed the emergent-norm theory of crowd dynamics. These researchers concede that social behavior is never entirely predictable, but neither are crowds as irrational. If similar interests may draw people together, distinctive patterns of behavior may emerge in the crowd itself. Crowds begin as collectivities, acting, and protest crowds – norms may be vague and changing as when, say, one person at a rock concert holds up a lit cigarette lighter to signal praise for the performers, and other follow suit. In short, people in crowds make their own rules as they go along.
Decision-making, then, plays a major role in crowd behavior, although casual observers of a crowd may not realize it. Crowd behavior reflects the desires of participants, but it is also guided by norms that emerge as the situation unfolds. Emergent-norm theory points out that people in a crowd take on different roles. Some step forward as leaders; others become lieutenants, rank-and-file followers, inactive bystanders or even opponents.
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