What is Groupthink?
Groupthink, a term coined by social psychologist Irving Janis (1972), occurs when a group makes faulty decisions because group pressures lead to a deterioration of “mental efficiency, reality testing, and moral judgment” (p. 9). Groups affected by groupthink ignore alternatives and tend to take irrational actions that dehumanize other groups. A group is especially vulnerable to groupthink when its members are similar in background, when the group is insulated from outside opinions, and when there are no clear rules for decision making.
What does Wikipedia say on the subject of Groupthink?
Groupthink is a psychological phenomenon that occurs within groups of people. It is the mode of thinking that happens when the desire for harmony in a decision-making group overrides a realistic appraisal of alternatives. Group members try to minimize conflict and reach a consensus decision without critical evaluation of alternative ideas or viewpoints. Antecedent factors such as group cohesiveness, structural faults, and situational context play into the likelihood of whether or not groupthink will impact the decision-making process.
The primary socially negative cost of groupthink is the loss of individual creativity, uniqueness, and independent thinking. While this often causes groupthink to be portrayed in a negative light, because it can suppress independent thought, groupthink under certain contexts can also help expedite decisions and improve efficiency. As a social science model, groupthink has an enormous reach and influences literature in the fields of communications, political science, social psychology,management, organizational theory, and information technology.
The majority of the initial research on groupthink was performed by Irving Janis, a research psychologist from Yale University. His original definition of the term was, “A mode of thinking that people engage in when they are deeply involved in a cohesive ingroup, when the members’ strivings for unanimity override their motivation to realistically appraise alternative courses of action” (Janis, 1972). Since Janis’s work, other studies have attempted to reformulate his groupthink model. ‘T Hart (1998) developed a concept of groupthink as “collective optimism and collective avoidance,” while McCauley (1989)  pointed to the impact of conformity and compliance pressures on groupthink decisions.