social network

Meaning: A social network is a set of people or groups (nodes) connected by social ties such as kinship, friendship, work, or online links. Networks carry social support (emotional, informational, tangible), norms, and influence. Ties differ in strength. Strong ties are close and frequent, as with family and best friends. Weak ties are acquaintances. Weak ties often bridge otherwise separate clusters, so they can bring new information, which is Granovetter's "strength of weak ties." People also tend to connect with similar others (homophily).

On the MCAT: A passage may describe behavior or a health outcome, such as smoking, obesity, or job finding, spreading through a community, and ask which tie type or network feature explains it. Expect questions linking networks to social support, social capital, and social contagion. Larger, more supportive networks are generally linked to better health outcomes. Online platforms may appear as a modern example.

Common confusion: A social network is not the same as a social group or social media. A group involves shared identity and interaction among members. A network is the pattern of ties, and two people in your network may never have met. Weak ties are not useless: they tend to give more novel information, while strong ties tend to give emotional support.