Belongingness is the human emotional need to be an accepted member of a group. Whether it is family, friends, co-workers, or a sports team, humans have an inherent desire to belong and be an important part of something greater than themselves. The motive to belong is the need for "strong, stable relationships with other people." This implies a relationship that is greater than simple acquaintance or familiarity. The need to belong is the need to give and receive affection from others.
Psychological needs 
Abraham Maslow suggested that the need to belong was a major source of human motivation. He thought that it was one of 8 basic needs, along with physiological, safety, self-esteem, and self-actualization. These needs are arranged on a hierarchy and must be satisfied in order. After physiological and safety needs are met an individual can then work on meeting the need to belong and be loved. If the first two needs are not met, then an individual cannot completely love someone else.
Other theories have also focused on the need to belong as a fundamental psychological motivation. According to one contemporary viewpoint, all human beings need a certain minimum quantity of regular, satisfying, social interactions. Inability to meet this need results in loneliness, mental distress, and a strong desire to form new relationships.
Several psychologists have proposed that there are individual differences in people's motivation to belong. People with a strong motivation to belong are less satisfied with their relationships and tend to be relatively lonely. As consumers, they tend to seek the opinions of others about products and services and also attempt to influence others' opinions. 
Evolutionary perspectives 
One reason for the need to belong is based on the theory of evolution. In the past belonging to a group was essential to survival. People hunted and cooked in groups. Belonging to a group allowed tribe members to share the workload and protect each other. Not only were they trying to ensure their own survival, but all members of their tribe were invested in each other's outcomes because each member played an important role in the group. More recently in Western society, this is not necessarily the case. Most people no longer belong to tribes, but they still protect those in their groups and still have a desire to belong in groups.
In order to be accepted within a group, individuals may convey or conceal certain parts of their personalities to those whom they are trying to impress. This is known as self-presentation. Certain aspects of one’s personality may not be seen as desirable or essential to the group, so people will try to convey what they interpret as valuable to the group. For example, in a business setting, people may not show their humorous side but they will try to show their professional side in an attempt to impress those present.
Group membership 
Individuals join groups with which they have commonalities, whether it is sense of humor, style in clothing, socioeconomic status, or career goals. In general, individuals seek out those who are most similar to them. People like to feel that they can relate to someone and those who are similar to them give them that feeling. People also like those that they think they can understand and who they think can understand them.
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