Selective amnesia is the strategic disowning of commitments, statements, or events that the person clearly knows occurred. Unlike a genuine memory lapse, the forgetting is patterned: recall stays crisp for anything that serves them and fails precisely where accountability would land. If you find that someone remembers your errors in detail but cannot recall a single promise they made to you, you are likely seeing the tactic, not a bad memory.
What makes it corrosive is not any single instance — everyone forgets — but the cumulative effect of the pattern. Each time you are asked to prove that a conversation happened at all, you spend energy defending your own perception, and the person doing the forgetting stays composed while you become the agitated one. Over time this can genuinely shake your confidence in your recall, which is the point: a target who no longer trusts their own memory is easy to overrule. Your certainty is data, especially when notes or messages back it up.
The defense is structural rather than argumentative. You will rarely win a live dispute over what was said, because the whole tactic is built to make that unwinnable. Moving agreements out of memory and into writing — a short confirming message, a shared note, a witness kept in the loop — removes the terrain the tactic needs. When forgetting is chronic and paired with other reality-distortion moves in a close relationship, it can be one thread of coercive control, and outside support is a reasonable next step.