Irrational decisions taken in a high conformity group is called

The correct answer is B) Group thinking, the concept known as Groupthink, coined by Irving Janis in 1972. It describes a situation where the desire for harmony in a tightly knit group overrides members' willingness to test ideas critically, so the group reaches poor or irrational decisions. The Bay of Pigs invasion (1961) is the classic case study.

• A) Creativity is about generating novel ideas. High conformity suppresses creativity rather than describing it.
• C) Informality refers to relaxed procedures or norms, not a defect in reasoning.
• D) Psychological vigilance is not the standard term. Vigilance means alertness, which is the opposite of what groupthink produces.

Core concept: the symptoms of groupthink include an illusion of invulnerability, self-censorship, pressure on dissenters and an illusion of unanimity. Remedies such as devil's advocacy, independent evaluation and encouraging dissent are standard points in Mains answers on committee decision-making and institutional accountability.

Trap: Aspirants pick Informality or Creativity because they sound like group-behaviour words, forgetting that the question asks for the defect in decision-making caused by conformity.