Group requires 2 or more people that connected by and within social relationships. John james portland: all groups are small (2) -most commonly group size: 2-7people, most are dyads (only group that dissolves when one leaves/also cannot be split to subgroups) Max number of ties: n(n-1) / 2 [n=#of people in a group] People in groups are linked by their membership. Networks interconnected individuals or groups; set of social or nonsocial objects that are linked by relational ties. People are not part of groups unless they perceive they are part of the group. Social identity: groups often share a common identity with one another, and they would know who is in their group, and those who are not. (henri tajfel) Creates a sense of we and us, and they. 1)relationship interaction: social side of group life (ex. 2)task interaction: behavior that is focused on work, project, plans and goals. Groups are united in their pursuit of common goals.