There are four main group formation theories
1.Propinquity Theory: As per this theory people affiliate with one another because of spatial or geographical proximity. This means that employees who have offices close to one another would form a group more easily. here, nearness is the only factor for group formation
2. Homer’s Theory: According to George C. Homans, “The more activities persons share, the more numerous will be their interactions and the stronger will be their shared activities and sentiments, and the more sentiments people have for one another, the more will be their shared activities and interactions.” So there are three main elements in this theory- Interaction, Activities and Sentiments. these three are linked with each other and gets affected by one another.
3. Balance theory: Proposed by Theodore Newcomb, the balance theory states that “Persons are attracted to one another on the basis of similar attitudes towards commonly relevant objects and goals. Once a relationship is formed, it strives to maintain a symmetrical balance between the attraction and the common attitudes. If an imbalance occurs, attempts are made to restore the balance. If the balance cannot be restored, the relationship dissolves.”
4.Exchange Theory: This theory is based on reward-cost outcomes of interactions. To be attracted towards a group, a person thinks in terms of what he will get in exchange of interaction with group members. A minimum positive level (rewards greater than costs) of an outcome must exist in order for attraction or affiliation to take place. Rewards from interactions gratify needs while costs incur anxiety, frustrations, embarrassment or fatigue. Propinquity, interaction and common attitudes all have roles in the exchange theory.