Dunbar's Circles of Friendship: Who Gets Your Saturdays

My phone holds 612 contacts. In the last 90 days I exchanged an actual conversation with 31 of them, and most of those were about parking, a landlord, or a shared document. The number of people I spoke to about anything that mattered was seven.

That ratio is roughly what Robin Dunbar’s research on social networks would predict. Dunbar’s circles of friendship are a model in which a person’s relationships sit in nested rings of about 5, 15, 50 and 150 people, each ring roughly three times the size of the one inside it, with closeness and contact frequency falling at every step outward. The practical answer to “who gets my Saturdays” is the innermost ring first, then the next, and almost nobody past that.

What are Dunbar’s circles of friendship?

Dunbar, an evolutionary psychologist at Oxford, laid out the full picture in “The Anatomy of Friendship” (Trends in Cognitive Sciences, 2018, vol. 22, pp. 32-51). The rings are usually named like this, and the contact rhythms in the right-hand column are the commonly cited summary of his survey findings, not rules he issued.

Ring	Typical size	Common name	Rough contact rhythm that keeps it alive
1	about 5	Support clique	Weekly, some form of contact
2	about 15	Sympathy group	Monthly
3	about 50	Affinity group	Every few months
4	about 150	Active network	Roughly yearly

The 5 includes family and is the group people go to in a crisis. The 15 add close friends, the 50 are roughly the guest list of a decent party, and the 150 are people you would stop and talk to if you met them at an airport. Dunbar extends the same tripling pattern outward to about 500 acquaintances and about 1,500 people you can put a name to.

Two things from the 2018 review matter for planning a week. First, the quality of a friendship depends on time invested in it, and time is capped, so the rings are partly a record of where your hours went. Second, Dunbar lists seven shared traits (the “seven pillars”) that predict friendship: language or dialect, place of origin, educational path, hobbies, worldview, music taste and sense of humor. The more you share, the more closeness a given amount of time buys.

Why do friendships fade without contact?

The best-known test of decay is Roberts and Dunbar (2011), “The costs of family and friends: an 18-month longitudinal study of relationship maintenance and decay,” Evolution and Human Behavior, 32(3), 186-197. They followed 25 students through the move from school to university. Emotional closeness to friends fell faster than closeness to relatives when contact dropped, and friendships were also more sensitive to a decline in shared activities. Kin relationships were less affected by the same drop in contact.

Sutcliffe, Dunbar, Binder and Arrow (2012, British Journal of Psychology, 103, 149-168) reviewed how this fits together. Their argument is that trust, which is a function of time invested, is what sorts people into rings, and that people trade off between rings because a day only has so many hours.

The sample in the 2011 study was small, young and in the middle of a transition, so treat the effect size as indicative. The reading most people take from it is that friendship needs maintenance, and the maintenance is mostly time spent together.

Is the number 150 real?

Disputed, and you should know that before you build a spreadsheet on it. Lindenfors, Wartel and Lind (2021, Biology Letters) re-ran the analysis behind “Dunbar’s number” using different primate datasets and methods and got widely varying answers. Their conclusion was that a neat cognitive ceiling of 150 cannot be derived from brain size, and that real social networks vary a great deal between people.

Dunbar has defended the figure with data from personal networks and from historical and small-scale societies, so the dispute is live and not settled. What survives either way is the shape: a few people who get a large share of your attention, and a long tail who get very little. The exact count of 5 or 15 matters less than noticing your own pattern.

How to run a 20-minute friend ledger

A friend ledger is a one-page record of who is in each ring and when you last spent time with them. It takes four to five steps and one pen.

1. Dump the names (5 minutes). Scroll your messages and call log for the last 90 days. Add anyone who would be hurt not to hear from you, even if you have not contacted them.
2. Draw four rings (3 minutes). Label them 5, 15, 50 and 150.
3. Fill the rings (5 minutes). Sort by how much of your week you would rearrange for the person, not by years known. If the center is crowded with eleven names, you have a different problem than friendship, which is that you have not decided.
4. Add last-contact dates (4 minutes). For the inner 15 only. Mark anyone whose gap is longer than the rhythm in the table above.
5. Book the gaps (3 minutes). One dated plan per marked name, within 14 days.

The mismatch to look for is between rings 1 and 2: someone you think of as inner-circle who gets monthly attention in practice, or someone you barely placed who gets weekly contact because they live nearby. For plans that cost little effort to organize, the ranking in things to do with friends, ordered by planning effort is a practical menu. If the ledger shows your recent circle is mostly the people who happen to sit near you, the friendship audit covers what to do about that, and the friendship recession looks at why adult friendships thin out structurally.

Can you move someone between circles?

The research says movement happens, in both directions, and that it follows contact.

Outward drift is the default. Roberts and Dunbar’s students lost closeness to friends when contact thinned, without any falling out. Nobody decided anything.

Inward movement takes repeated, shared time. The seven pillars suggest where to start: a friend who shares your sense of humor and hobbies gains closeness faster per hour than one who shares only history. In practice that means picking activities, not just conversations. A weekly run or a standing Thursday dinner does more than a long catch-up call every six months.

Ring 2 to ring 1 is the move that matters. Since the inner five is the crisis group, promoting a person means giving them a role. Ask for something small and real: a ride, an opinion on a decision, a favor. Being asked is the signal that tells them where they sit.

Demotion is allowed. Because ring sizes are limited by time, adding someone to the five means someone else slides to the fifteen. Plan that move on purpose, with a warm message and a monthly coffee, rather than letting it happen through silence.

Which five people should see you at your worst morning?

Here is how the rings connect to waking up. The people in your inner five are the ones whose view of you is heavy enough to change what you do. That is a good test for who should be your witnesses on a morning you do not feel like getting up.

DontSnooze works on that principle: when the alarm fires you have 30 seconds to record a short video showing you are awake, and if you do not, a random photo from your camera roll goes to friends you picked. The app asks you to choose those friends. Pick from ring 1 or ring 2, since a stranger from ring 4 seeing a stray photo costs you nothing, and a sibling or your best friend seeing it costs you something real. The friends you rank highest on the ledger are the ones you would least want to disappoint, which is why the mechanism has any bite.

Not everyone’s inner ring should be recruited for this, and a ring with only two names is a reason to do the ledger, not a reason to skip it. If you are not sure whether to involve people close to you at all, the case against accountability partners is a useful counterweight.

For a ready-made format for the people you do pick, see Benjamin Franklin’s Junto, a Friday-night friend club with a fixed list of questions.