The attraction to and acceptance of groups

An individual may either have a positive attraction if he is motivated to become or remain a member or a negative attraction if he is indifferent to membership. A group with a high degree of positive attraction becomes more adhesive. This group can mobilize their energies in support of group goals and maintain adherence to group standards.
Acceptance of a group is the degree to which the group employs role prescriptions to influence an individual’s behavior. With positive acceptance the individual embraces the sanctions imposed and will not deviate from group norms. Neutral acceptance occurs when members are indifferent or tolerant of the members’ lack of conformity. Negative acceptance means that members treat the individual as not belonging to the group and being eventually excluded from membership.
Full “psychological membership” is obtained when an individual is both positively attracted to the group and positively accepted by it. “Psychological non membership”, on the other hand, is characterized by neutral attraction together with neutral acceptance.
“Marginal membership” features an indifference towards membership and a “rebellious membership” occurs when an accepted individual desires not to belong to the group.

Further reading:

 Multiple memberships of groups

Group Dependence