Final answer:
Groupthink is indicated by a group's perceived invulnerability, moral correctness, self-censorship to maintain consensus, and an illusion of unanimity. It hinders critical thinking and can be prevented by valuing diverse opinions and thorough decision-making strategies.
Step-by-step explanation:
A sign that a group is suffering from groupthink is when members perceive the group as invulnerable or infallible, essentially believing that it can do no wrong. Additionally, signs of groupthink include the belief that the group is morally correct, the occurrence of self-censorship by members to maintain consensus, and the illusion of unanimity within the group. This phenomenon often leads to the quashing of dissenting opinions and stereotypes towards individuals with differing views, which can hinder critical thinking and result in poor decision-making processes within the group.
Groupthink can often be prevented through strategies such as inviting outside opinions, private voting, having the group leader withhold his or her position, and exploring all viewpoints thoroughly. It is crucial for groups to value diverse perspectives and critical analysis over mere cohesion to avoid the pitfalls of groupthink.