Groupthink, defined by Janis, is “a deterioration of mental efficiency, reality testing, and moral judgment that results from in-group pressures.” Groupthink is a phenomenon when a group of people get together and start to think collectively with one mind. The group, as a whole, tends to take irrational actions or overestimate their positions or moral rightness. Groupthink can have some benefits. When working with a large number of people, it often allows the group to make decisions, complete tasks, and finish projects quickly and efficiently. However, this phenomenon also has costs as well. The suppression of individual opinions and creative thought can lead to poor decision - making and inefficient problem - solving. Groupthink tends to occur in isolated groups, especially in groups with no clear rules for decision making and in groups where all of the people involved have similar backgrounds. It is destructive to effective thinking. Irving Janis devised eight symptoms indicative of groupthink: 1) Overestimations of the Group • Illusions of Invulnerability: Creating excessive optimism and encouraging risk taking. • Illusions of Morality: Unquestioned belief in the morality of the group, causing members to ignore the consequences of their actions. 2) Closed - Mindedness • Rationalizing: Warnings that might challenge the group's assumptions. • Stereotypes about the Out group: Stereotyping those who are opposed to the group as weak, evil, biased, spiteful, impotent, or stupid. 3) Pressures toward Uniformity • Self - Censorship: Halting the ideas that deviate from the apparent group consensus. • Illusions of Unanimity: Among group members, silence is viewed as agreement. • Direct Pressure: This is to conform placed on any member who questions the group, couched in terms of "disloyalty" • Mindguard: Self - appointed members who shield the group from dissenting information. Irving Janis set up three causes of groupthink: 1) Cohesiveness 2) Structural Faults of Group 3) Provocative Situational Context