Which of the following is NOT a symptom of groupthink?

A) The existence of self-appointed mindguards
B) The self-censorship of dissenting ideas
C) Social pressures encouraging excessive dissent
D) Illusions of invulnerability
E) Defective decision-making strategies

Groupthink is characterized by a high level of cohesiveness and a strong desire for unanimity that leads members to minimize conflict and reach consensus without critical evaluation of alternative viewpoints. Symptoms of groupthink include the existence of self-appointed mindguards, self-censorship of dissenting ideas, illusions of invulnerability, defective decision-making strategies, and pressure on dissenters to conform. Social pressures encouraging excessive dissent, as stated in option C, would actually be a counterforce to groupthink. Therefore, not being a symptom of groupthink.