Here is a Brilliant assessment of how to test the tendency for group think, by Irving, which is worth noting. To make groupthink testable, Irving Janis devised eight symptoms indicative of groupthink (1977).
Type I: Overestimations of the group—its power and morality
- Illusions of invulnerability creating excessive optimism and encouraging risk taking.
- Unquestioned belief in the morality of the group, causing members to ignore the consequences of their actions.
Type II: Closed-mindedness
- Rationalizing warnings that might challenge the group's assumptions.
- Stereotyping those who are opposed to the group as weak, evil, biased, spiteful, impotent, or stupid.
Type III: Pressures toward uniformity
- Self-censorship of ideas that deviate from the apparent group consensus.
- Illusions of unanimity among group members, silence is viewed as agreement.
- Direct pressure to conform placed on any member who questions the group, couched in terms of "disloyalty"
- Mind guards — self-appointed members who shield the group from dissenting information.
Groupthink, resulting from the symptoms listed above, results in defective decision-making. That is, consensus-driven decisions are the result of the following practices of groupthinking
- Incomplete survey of alternatives
- Incomplete survey of objectives
- Failure to examine risks of preferred choice
- Failure to reevaluate previously rejected alternatives
- Poor information search
- Selection bias in collecting information
- Failure to work out contingency plans.
Janis argued that groupthink was responsible for theBay of Pigs Invasion 'fiasco' and other major examples of faulty decision-making. The UK bank Northern Rock, before its nationalisation, is thought to be a recent major example of groupthink. In such real-world examples, a number of the above groupthink symptoms were displayed.
