Old Friendship Groups Have A Fixed Cast

A friendship group that has existed for twenty years is usually made up of the same people it started with. New members are added rarely, and the reasons are structural.

The group's content is its history

Long-standing groups spend a large share of their time on shared reference: things that happened, running jokes, the retelling of episodes everybody was present for.

A newcomer cannot participate in that. They can be told the stories, but being told a story is a different activity from remembering it together.

So the newcomer sits through the group's main pastime as an audience, which is pleasant for an evening and unsustainable as a position.

Nobody is responsible for integration

In a pair, the host is obviously responsible for including a new person. In a group of eight, responsibility is diffuse and therefore unassigned.

Each member reasonably assumes somebody else is doing it, and the newcomer is left with the person who brought them, which reproduces the pairing rather than dissolving it.

This is why introductions into groups succeed far more often when one member explicitly takes the job.

Adding a person changes the group's behaviour

Established groups have settled norms about what can be said, how far a joke goes and which subjects are open. Those norms are unwritten and calibrated to the people present.

A new member means the norms are provisional again, and everybody moderates slightly until they are re-established.

That moderation is a real cost, and it is why groups sometimes prefer the evening without the addition without anybody saying so.

Partners are the usual exception

The people who do enter established groups are almost always attached to an existing member, because that supplies both a sponsor and a reason for repeated attendance.

Repetition is what does the work. After enough occasions the newcomer has their own shared history with the group and stops being anybody's guest.

The awkward middle period is unavoidable and generally shorter than it feels from inside it.

What a closed group loses

Fixed groups shrink over time, since people move, drift and die and nothing replaces them. A group that never recruits has a fixed lifespan.

They also become less useful as a source of new connection, because everybody's networks were merged decades ago and there is nothing new circulating.

Groups that stay lively tend to recruit slowly and deliberately, usually through activity rather than through invitation to a purely social occasion.