Final answer:
The degree to which group members stick together is called social solidarity or group cohesion, reflecting the social ties based on shared characteristics or beliefs, contributing to a group's unity and success.
Step-by-step explanation:
The degree to which group members stick together and the strength of their relationships is known as social solidarity or group cohesion. This concept reflects the social ties that bind a group, which can be based on kinship, shared location, religion, shared values, or practices. A classic example of this is described by Ibn Khaldun in his observation of the military and political success of nomadic groups, attributing their success to the strong solidarity among the Berber tribes. Group cohesion is evident when individuals identify with an in-group, seeking approval, showing loyalty, and maintaining or improving status within that group. It is also associated with the tendency for humans to form relationships with those who are similar, a phenomenon known as homophily. The larger a group becomes, especially as part of a movement, the more attention it garners and pressure it can exert toward a goal. Yet, it also faces increasing risks for division and a reduction in cohesion. Group beliefs and commitment also contribute to group cohesion, especially in groups formed around specific ideologies or doctrines, such as religious groups.