Graceful forgetting

The gradual reduction of an earlier pattern's influence as an adaptive memory learns changing patterns. It is useful when current knowledge should take priority over reproducing every past observation.

Old-pattern fidelity measures retention; falling fidelity can be the intended consequence of adaptation. It still needs to be measured alongside learning of the new patterns. Abrupt, unwanted loss of a needed skill is a different issue: catastrophic forgetting.

HeatherDB's competitive mode can exhibit this behaviour. It does not promise a fixed forgetting schedule, expiration, or removal of all historical influence. See Learning and graceful forgetting and Choose a memory mode.