# Tweet by [@keefmoon](http://twitter.com/keefmoon) on 2021-07-16 18:57:08 > [!INFO] Archived from [original tweet](http://twitter.com/keefmoon/status/1416109665675513865) In reply to: [@keefmoon](http://twitter.com/keefmoon/status/1416109662492053506) My guess is that the brain has a memory playback mechanism that changes as the rest of the brain does, and old memories are in an increasingly unrecognisable format for playback.