social group

Meaning: A social group is two or more people who interact regularly and identify with one another, with shared expectations and a sense of "we." It differs from an aggregate (people in the same place without sustained interaction, such as passengers at a bus stop) and from a category (people sharing a trait, such as age, who need not interact). Primary groups, like family and close friends, are typically small, intimate and long-lasting. Secondary groups, like coworkers or a lecture class, are usually larger, more impersonal and organized around a goal. An in-group is one a person belongs to and identifies with; an out-group is one they do not.

On the MCAT: A passage describes a gathering and asks you to classify it, or to predict how membership shapes behavior, such as favoritism toward the in-group and bias against out-groups. Simmel's terms also appear: a dyad (two people) is the most intimate but ends if one member leaves, while a triad (three) is more stable but allows two members to form a coalition against the third.

Common confusion: Students call any crowd a group. Interaction plus shared identity is what makes a group, so strangers at a bus stop are an aggregate. Primary versus secondary depends on the quality of the ties, not size alone, and a secondary group can develop close bonds over time.