Implicit memory for visual objects and the structural description system

Several experiments are described in which priming or implicit memory for visual objects was investigated. In one set of studies, subjects were shown line drawings of unfamiliar objects that were either structurally possible or structurally impossible. Implicit memory was assessed with a possible/impossible object-decision task, and explicit memory was assessed with a recognition task. The results revealed significant priming for possible objects following study tasks that required encoding of three-dimensional object structure; semantic/elaborative study processing enhanced explicit but not implicit memory. No priming of impossible objects was found. An experiment using familiar objects also revealed that priming, but not explicit memory, was independent of semantic/elaborative study processing. It is suggested that priming of visual objects depends on a presemantic system that is dedicated to the representation of object form and structure and can function independently of episodic memory.