A discussion group once expected replies within a day. A few members become busy, others adjust, and eventually a week feels normal. The written welcome message still promises quick responses, but the lived expectation has changed.

“Norm drift” describes this gradual movement in what people expect. Repeated behavior, changing membership, and responses to exceptions can move the group away from its earlier understanding without a formal decision to change it.

The old rule can survive on paper

Simple coordination experiments have produced shared conventions through repeated interaction without central direction. A discussion group’s response times also depend on practical constraints: people may start taking longer because their available time changes, and others then adjust what they expect.

Drift may be useful adaptation or unnoticed deterioration. Slower replies may reflect a healthier pace, or make newcomers feel ignored. The judgment depends on what the practice does for participants, not simply on whether it matches the past.

Comparing the formal account with everyday expectations can reveal the change. The next conversation can then concern what the group wants to preserve or revise, rather than blaming individuals for violating a rule that the collective has quietly stopped following.

Real cases