Backward Masking

From SkepticWiki

In cognitive psychology, refers to the use of a bright visual stimulus immediately after a single-frame visual stimulus containing a subliminal message. This prevents the viewer from seeing an afterimage of the frame, which would allow a conscious evaluation of the subliminal message. (See psychorama).

In popular music, "backward masking" incorrectly refers to backmasking, or hiding messages in sound recordings that are audible when played backward.