Group Definition

There is no consensus among social psychologists on the defining characteristics of a group. Nearly all definitions, however, emphasize that a group is not a mere aggregation of individuals. Rather, two or more individuals become a group to the extent that they are bonded together in some way, which generally means that they interact and influence one another and share perceptions of themselves as a group. By these criteria, one’s immediate family is a group, and so are a sport team, an airline flight crew, and a support group. But a social category such as members of the same race or gender is not a group—nor is an audience attending a concert, the line of people at a ticket window, or all the students at a university. Recognizing that such distinctions are not as clear-cut as they appear, some social psychologists have argued that various social aggregates are best viewed as falling along a continuum of groupness based on certain characteristics.

Background and History of Groups

GroupThe idea that groups have properties distinct from those of their individual members was controversial in the early history of social psychology. Focusing on Gustave LeBon’s concept of the group mind, psychologists in the 1920s debated the epistemological status of groups. One side of the debate argued that groups are real entities with emergent characteristics; the concept of the group mind, for example, suggests that groups have a mind of their own, a unifying mental force that transcends the consciousness of the individuals that constitute the group. The other side of the debate denied the reality of groups, contending that only individuals are observed, not groups; psychological processes occur only in individuals, and actions or processes attributed to groups are nothing more than the sum of actions of the individual group members.

Eventually the concept of group mind was rejected, primarily because there was never any solid scientific evidence to support it. As research on groups flourished in the 1930s, 1940s, and 1950s, researchers accepted the reality of groups and identified several verifiable group properties. Much of this research was influenced by Gestalt psychology, a school of thought that emphasizes that an individual’s experience consists of integrated whole patterns that are not reducible to the sum of elements of the whole. One line of inquiry proposed, for example, that a bunch of people constitutes a group to the extent that they form a Gestalt; that is, they are perceived as being a coherent entity rather than independent, unrelated individuals. Furthermore, individuals’ intuitive perceptions of the quality of groupness depend on the extent to which a collection of people possesses certain group characteristics, including small size, similarity, a high level of interaction, and shared goals.

Group Size

In general, the larger the collection of people, the less likely they are to possess other characteristics that define a group and the less likely they are to be perceived as a group. Research indicates that most groups are small, usually two or three people and seldom more than five or six. In fact, much of the research on groups focuses on groups of this size or slightly larger, such as families, friendship cliques, work crews, and committees, in which people engage in regular face-to-face interaction. As group size increases, the nature of the group changes. It becomes less intimate and satisfying to members, and it becomes more complex, its activities more difficult to coordinate.

Group Member Variability

Each member brings to the group personal attributes such as his or her sex, age, race, and education as well as opinions, interests, and abilities. Research shows that members of the same naturally occurring group tend to be similar to one another on such qualities but different from members of other groups. Ingroup homogeneity is thought to exist for a variety of reasons: Similar people are attracted to similar activities that bring them together; they are recruited from the same social network, which also tends to be similar; and similarity increases satisfaction and commitment to the group. Diversity within groups can negatively affect relations among group members, creating miscommunication, division, and conflict, but by providing a variety of skills and knowledge, diversity also can make a group more flexible and innovative and better able to accomplish group tasks.

Group Structure

Perhaps the most essential defining characteristic of a group is the pattern of relationships among group members, referred to as group structure. Patterned relations may exist along several dimensions—for example, attraction, communication, and power—so that social psychologists seldom think of groups as a unitary structure.

Group Cohesion

The dimension of group structure most often studied is a group’s cohesion or cohesiveness. Cohesion derives from the pattern of attraction of members toward one another and toward the group as a whole; in a cohesive group, members like one another, are tightly knit, identify with the group, and want to remain in it. Compared with groups low in cohesion, highly cohesive groups, such as adolescent peer groups, sport teams, and military squads, are more satisfying to their members but also have greater influence over members and produce greater pressures to conform. In general, highly cohesive groups are more productive and outperform less unified groups with one notable exception: Cohesive groups are less productive when group norms support a low level of productivity.

Attraction Structure

General attraction to the group is indicative of group cohesion or unity, but variations within the group in how much members like or dislike one another is indicative of a form of structural differentiation. By asking group members who they like best and least or with whom they would choose to work, social psychologists have identified patterns of interpersonal attraction within groups, including the formation of subgroups or cliques. As groups increase in size and diversity, cliques are increasingly likely to form. Members of cliques tend to reciprocate choices (if A likes B, B likes A) and also tend to be more similar to one another than to other members of the group.

Role Structure

Within every group, members develop expectations concerning how people in particular positions ought to behave. These shared expectations, called roles, may be defined formally, as in most work groups, or may evolve over time and be tacitly understood. Airline flight crews, for example, often consist of three positions— captain, first officer, and flight engineer—each of which is expected to perform specific tasks related to flying a plane. In many groups, various group roles such as initiator, coordinator, and harmonizer emerge to meet two basic demands: to accomplish the group’s task and to maintain harmonious relationships among group members.

Status Structure

Roles are often associated with status, which refers to a person’s power (ability to influence others) and authority (the right to exert power) within a group. Virtually all groups develop a status structure in which some members have higher status than others. In an airline flight crew, there is a clear status hierarchy, with the captain, who makes major command decisions and leads the crew, on top, and the flight engineer on the bottom. Two general factors seem to affect the development of status in most groups: the characteristics and abilities members bring to a group, and members’ contributions to the group goal. In a jury, for example, a doctor may be assigned a higher status than a laborer, and persons who smooth over disagreements and move the group toward a decision are likely to have more status than others.

Communication Network

Groups also differ in their patterns of interaction and communication. The flow of communication in many groups follows the status structure, with most communication either directed downward, from superiors to subordinates, or among members of equal status. Early studies of communication networks focused on the extent to which communication within a group flowed through a single person or position. In the most centralized networks, all lines of communication are directed to and from a single group member, whereas in a decentralized network, each member has an equal number of communication lines to others in the group. Research suggests that centralized networks are most efficient in solving simple tasks, but decentralized networks work best for more complex and multifaceted tasks.

Group Culture

Besides the patterned relations among members, groups also develop a culture of their own: a set of shared ideas and customs that guide group members’ actions and interpretations of the group experience. Elements of group culture include norms, or ideas about how group members ought to behave, as well as values, beliefs, customs, and symbols that express the group’s identity. Although some elements of group culture are adapted directly from the larger culture, other elements evolve within the group, so that every group creates its own unique culture. Members of all airline flight crews, for example, have a common knowledge of how to perform their jobs and also may share certain values and beliefs about their work. But, in addition, as crew members interact with one another, they develop unique customs such as special names or jargon, traditions, and stories about group activities. Becoming a new member of an existing group is largely a matter of learning the group’s culture.

Importance of Groups

Groups provide vital links between the individual and society. On one hand, groups satisfy basic individual needs: Through groups, children are raised, shelter and protection are provided, people gain important information about themselves, and people satisfy an inherent desire to have human contact and to bond with others. At the same time, groups support and sustain larger organizations and society by teaching values and societal norms, by exerting pressure on individuals to conform, and by providing a means to solving problems.


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