As teams move through Tuckman's stages of team-building, they increase acquaintance, attraction and committment to the team. These are most pronounced in the "norming" stage where unwritten expectations about conduct are formed. As cohesion increases, norms are used to set standards of performance, and members exercise sanctions to increase conformity and reduce deviance from norms. When a very strong culture is built with high conformity, group think can also occur. The effects of group think combine to reduce innovation and decision making effectiveness. The same factors that build cohesion can be facilitated to reduce cohesion and group think.
Cohesion refers to the attraction a group of people have to relate, maintain group membership, and be identified as a group. It is desirable for teams to build rapid cohesion because it tends to unify and align efforts, enable group pressure for sanctioning deviance (see below), and increase team esprit. Teams that have high cohesion also tend to develop strong culture and norms, have high morale and satisfaction, are loyal and committed, and are productive.

Cohesion can be enhanced by these factors:

Sources of Norms
Norms are the usually unwritten, implicit expectations about "the way we do things here." They are standards of performance and behavioral guidelines about what is and is not acceptable. They are formed in four ways: