Groupthink is the term social psychologist Irving Janis applied to the
decisions often reached by overly cohesive groups. When a tightly knit group
is more concerned with preserving group solidarity and uniformity than with
objectively evaluating all possible alternatives in decision making. In
addition, individual members of the group may hesitate to voice any dissent.
The group may also cast aside any opposing views from outsiders and the group
may begin to believe that it is invulnerable and incapable of making mistakes.
Some argue that even plans bordering on madness can be hatched and adopted
when group think prevails (Wood, S.E. & Wood, E.G., 1996. The world of
psychology [2nd. Ed.] Needhan Heights, MA: Allyn and Bacon).
One of Janis's text is: Janis, I. L. (1982). Groupthink: Psychological studies
of policy decisions and fiascoes (2nd. Ed.) Boston: Houhton Mifflin.
Hope this helps,
Tony A