contagion across social networks: for example, the spread of obesity across social networks appears to be influenced by perceptions of social norms about the acceptability of obesity and related health behaviors (e.g., food consumption, inactivity) among network members who are socially close, rather than members who are simply geographically close (Christakis and Fowler 2007; Smith and Christakis 2008). In a more fundamental way, greater social connection may foster a sense of “coherence” or meaning and purpose in life, which, in turn, enhances mental health, physiological processes, and physical health (Antonovsky 1987).
