Canon-Bower and Salas added there is also not a singular way that knowledge can be “shared” among team members. Some common knowledge must be held by all members of a team, particularly as it relates to the specific task. Other types of knowledge are shared by being distributed or apportioned across the team members. Certain knowledge is complex or specialized, and it is unrealistic to expect all members of a team to possess this level of knowledge equally. Thus what is important is that the knowledge resides within the team as a team, not held by each team member. Shared knowledge is common in military combat teams and surgical teams. Cross-training (where team members learn to perform each other’ task) has been found to enhance shared mental models (Marks et al., 2002)
As compelling as the evidence is for shared mental models for effective team performance, there is a potential dark side to team members “thinking alike.” The phenomenon is called groupthink. Noted problems in history that arose from groupthink are the Bay of Pigs invasion of Cuba in the 1960s and the explosion of the Challenger space shuttle in the 1980s. Groupthink refers to a deterioration in the cognitive processing caused by team members felling threatened by external forces. The defects in decision making include incomplete consideration of options and alternatives, poor information search, and selective information processing. Groupthink is a model of thinking in which team members consider consensus to be more important than rational, independent thinking. Some symptoms are the illusion of team vulnerability, the false assumption of the team’s morality, stereotyping of opposing groups, the illusion of group unanimity, and the emergence of a process that keeps opposing viewpoints from the team’s consideration. The team, operating with a siege mentality, fails to perceive environments correctly and looks for confirming evidence that it is being threatened. Choi and Kim (1999) noted that the conventional interpretation of groupthink is a negative influence on performance. The team is used in reference to fiascoes like the Bay of Pigs invasion. However, although they found that some dimensions of the groupthink phenomenon (such as suppressing dissenting opinions) were related to negative team performance, some other dimensions (such as a strong sense of group identity) in fact were related to positive team performance. Turner and Horvitz (2001) concluded that groupthink is more likely found in teams that have a strong sense of social identity. In such cases team members often feel compelled to maintain and enhance their evaluation of the team and its action. Furthermore, members become motivated to protect the image of the team. When the image is questioned by a collective threat, the response among members is to seek concurrence about the threat and, by virtue of that, attain greater acceptance as bona fide team members. A threat to an individual member of a team is not as likely to engender groupthink as is a threat to the entire team.