As noted last week, Robin Dunbar, who has done amazing research into close personal relationships, is best known for "Dunbar's Number" - his finding that the typical friends network contains about 150 people (as discussed in a recent post by Arnold Kling). Yet as I also noted long ago in my blog post "Joining the Band", there are actually multiple Dunbar numbers, each roughly 3x more or less than the next one in the series.
Thus above the 150 mark one finds circles of ~500 acquaintances, ~1500 people whose names you know, and ~5000 people whose faces you recognize. Below the 150 mark one finds circles of ~50 good friends, ~15 best friends (which Dunbar also calls a "support clique"), ~5 close friends (a "sympathy group"), and ~1.5 intimates. (Why 1.5? Men typically have only their spouse in their intimates group, whereas women often have a spouse and a female BFF.)
The smaller the group, the greater the frequency of contact (phone calls, lunches, shared activities, etc.), the greater the emotional closeness and feeling of mutual understanding, and the greater the willingness to help each other.
Why are some people closer to the center of your circles of friendship, and others out toward the periphery? That's where the seven pillars of friendship come in: the more of the pillars you have in common with someone (e.g., similar worldview AND grew up in the same location AND similar sense of humor), the more likely they are to be closer to the center.
Personally I found these insights to shed light on my family relations and friendships, but they have implications for the working world, too. For instance, the makers of GoreTex insist on limiting the size of their factories to 150 people. Startup companies typically go through inflection points as they pass certain milestones (e.g., with more than ~15 people you need more policies and procedures). Teams become ineffective if they have too many people in them (in my experience, much more than 5 is too many). And so on.
Dunbar's 2021 book Friends thoroughly summarizes his research, and I highly recommend it if you're curious to learn more.
(Cross-posted at philosopher.coach.)
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