VISUAL MEMORY FOR NOVEL SHAPES - IMPLICIT CODING WITHOUT ATTENTION

Implicit memory for novel shapes was explored with a negative priming paradigm. The results show that representations of shapes, formed in a single trial and without attention, can last without decrement across 200 intervening trials and with temporal delays of up to a month. No explicit memory of the shapes was available, either immediately or aft er a delay. There were consistent individual differences in the amount of negative priming shown, and some participants showed only facilita tion. There was a trend toward increased facilitation across time, as if the memory of the shape survived longer than an ''action tag'' atta ched to it, which specified whether it should be attended or ignored. The results demonstrate a surprising combination of plasticity and per manence in the visual system and suggest that the roles of both attent ion and repetition may be to ensure voluntary retrievability rather th an to form a lasting memory.