Cynthia Baron Rabe in her book “Innovation Killer” is speaking about Groupthink as:
” a well documented and often detrimental human tendency to go along with decisions that the majority of a group will accept.”
Sometimes is enough to keep your mouth shut during the group conversation and it will mean that your think like others in the group, which can lead to problems later.
Groupthink must, for sure, be avoided in brainstorming sessions, as it can destroy it. Shortly, groupthink is the opposite to innovation & innovation culture.