Hypnotic amnesia

Amnesia may be induced by the use of suggestion usually under hypnosis (in a trance state). Memory of the trance state is vague and fragmentary, especially if the suggestion is that it should be forgotten. Analogous phenomena may be found with collective memory. Public opinion may be hypnotized by suitable processes (perhaps fascist propaganda is an extreme example) and these may well cause awareness of the hypnotized state to be collectively repressed.