dyad

Meaning: A dyad is a social group made of two people. Georg Simmel contrasted it with the triad, a group of three. Each member is half of the group, so a dyad depends on both people. If one leaves, the group no longer exists. This tends to make dyads intense, personal and highly interdependent, but less stable than larger groups. No third person is present to mediate a dispute or tip a decision.

On the MCAT: Passages on group size, social interaction or relationships ask you to compare a dyad with a triad or a larger group. A dyad typically has the closest bonds and is the most fragile. A triad can form a coalition (two members against one), can use a mediator, and can continue as a dyad if one member leaves. As groups grow, they tend to become more formal and stable, while the bond between any two members becomes weaker. Typical examples are a married couple, two close friends, or a parent and child.

Common confusion: Students treat dyad as a synonym for a close relationship or a primary group. A dyad is defined by size, two people, not by emotional closeness. Some dyads, such as a clerk and a customer, are impersonal. Another error is to assume that a triad is simply more harmonious. The third member adds stability against dissolution, but also creates the chance of coalitions and exclusion.