What is groupthink and how does it work? Provide an example from the textbook.

Groupthink is a group dynamic that affects decision making. It is most likely to occur when highly cohesive groups demand absolute conformity and punish members who violate group norms or threaten to undermine consensus. Although groupthink helps maintain group solidarity, it can also short-circuit the decision-making process and let a desire for unanimity prevail over critical reasoning. Under the influence of groupthink, a group may begin to feel invulnerable and morally superior. Members who would otherwise wish to dissent may instead censor themselves and cave in to peer pressure. The textbook cites the Challenger disaster, the U.S. invasion of Iraq, and the Penn State child sexual abuse scandal as examples of groupthink.