Small increments accumulate with little visible effect until the system flips rapidly to a new state.
Grodzins's tipping in neighbourhood racial composition, popularised by Gladwell in 2000. The mechanism is the threshold model, and the popularised version often skips the mechanism entirely.
In practice
- Small increments accumulate with little visible effect until the system flips.
- A neighbourhood's shops change one at a time for a decade and the character changes in a single year, which is when residents notice.