What is the main contributing factor that causes groupthink in collaborative decision-making?

The main contributing factor that causes groupthink in collaborative decision-making is the desire for harmony and conformity within the group, which suppresses dissenting opinions and critical evaluation of alternative viewpoints. This desire for cohesion can lead group members to avoid expressing doubts or disagreements, fearing that they will be ostracized or viewed negatively by the group. Several factors contribute to this pressure for conformity, including a strong sense of group identity, a directive leader who promotes a particular solution, and isolation from outside perspectives. When these factors are present, group members may overestimate the group's competence and invulnerability, leading to a collective illusion of unanimity and a reluctance to challenge the prevailing view, even if they have private reservations. This suppression of critical thinking can result in poorly reasoned decisions that fail to consider all relevant information and alternative possibilities.