SIZE INVARIANCE IN VISUAL OBJECT PRIMING

The magnitude of priming resulting from perception of a briefly presented picture of an object in an earlier trial block, as assessed by naming reaction times (RTs), was independent of whether the primed object was presented at the same or a different size as when originally viewed. RTs and error rates for "same" responses for old-new shape judgments were much increased by a change in object size from initial presentation. We conjecture that this dissociation between the effects of size consistency on naming and old-new shape recognition may reflect the differential functioning of 2 independent systems subserving object memory: 1 for representing object shape and the other for representing its size, position, and orientation (metric attributes). Allowing for response selection, object naming RTs may provide a relatively pure measure of the functioning of the shape system. Both the shape and metric systems may affect the feelings of familiarity that govern old-new episodic shape judgments. A comparison of speeded naming and episodic recognition judgments may provide a behavioral, noninvasive technique for determining the neural loci of these 2 systems.