Christopher Allen writes a stimulating blog called Life With Alacrity — like Niel Robertson, his occasional posts are long and worth a slow, quiet read. His two most recent posts are must-reads for anyone interested in community, sociology, group / team dynamics, and personal relationships.
Community by the Numbers: Group Thresholds — He explains the optimal sizes of different groups. For example, 7 is the optimal number of people in a tight-knit "working group" — say, a small business. It's also a number of people that "feels right" at a dinner party. 13 he calls the "Judas Number" — at this threshold group behavior changes in a way that hurts the overall efforts until the size grows to a new threshold point more conducive to teamwork.
Community by the Numbers: Personal Circles — He explains the different types of relationships in our life and the maximum of each type the average person can maintain. Obviously there's variance in these numbers depending on the person.
- Support Circle – People you turn to in moments of severe emotional or financial distress: 3-5
- Sympathy Circle – People you turn to for sympathy and people whose death would be devastating to you: 10-15
- Trust Circle – People you have emotional closeness to, people you would send a Christmas card to: ~150
- Emotional Circle – People you "like" and can have a non-mutual emotional connection to (weak ties): ~300
- Familiar Strangers – People whose faces you recognize but you know nothing about them: 1000+? (No clear studies on # of people we can recognize.)
(hat tip to Eliezer Yudkowsky for the pointer to Allen's blog.)