A group is said to be in a state of cohesion when its members possess bonds linking them to one another and to the group as a whole. According to Festinger, Schachter, and Back (1950), group cohesion develops from a field of binding social forces that act on members to stay in the group. Groups that possess strong unifying forces typically stick together over time, whereas groups that lack such bonds between members usually disintegrate.
The Role of Group Size
Since it is easier for fewer people to agree on goals and to coordinate their work, smaller groups are often more cohesive than larger groups. Group cohesiveness may suffer, though, if the group lacks enough members to perform its tasks well.
An intimate community is one in which some members recognize and are recognized by all of the others, and most of the members recognize and are recognized by many of the others. This is in contrast to (usually larger) communities where members are known and interact mostly within their own subgroup, such as a neighborhood, department, or occupation. The contrast between the two types is illustrated by comparing hamlet with town, military company with battalion, parish church with diocese, or a country school with a huge urban one.
The Limits of Group Size
Intimate communities seldom have more than about 150 members, a number derived from the "Dunbar's Number" concept. This is the suggested cognitive limit to the number of people with whom one can maintain stable social relationships. These are relationships in which an individual knows who each person is, and how each person relates to every other person. While no precise value has been unanimously agreed upon, it has been proposed to lie between 100 and 230, with a commonly used value of 150. The concept is based on studies of social animals, which have shown a correlation between the typical frontal brain capacity the members of a species has and the maximum size of the groups in which they live. Like animals, the number of relationships the human brain can handle is large but not unlimited .
Diagram of a Network
Individuals in groups are connected to each other by social relationships.