The University of Sussex

On the representation of object structure in human vision: evidence from differential priming of shape and location

Shimon Edelman, Fiona Newell

Theories of object representation can be classified as structural, holistic or hybrid, depending on their approach to the mereology and compositionality of shapes. We tested the predictions of some of the current theories in three experiments, by quantifying the effects of various priming cues on response times to 3D objects. In experiment 1, there were two possible locations for the stimulus components: left-right and top-bottom. The prime could be identical to the stimulus, identical in location but with different parts, identical in the complement of differently located parts, or altogether different. Both location and part identity effects were significant. In experiment 2 we added a part-neutral (empty frame) prime condition; the effect of location, but not of part, remained significant. In experiment 3, which included an additional location-neutral prime condition, only the location effect, again, was significant. These findings are not entirely compatible either with the structural description theories of representation (which predict priming by ``disembodied'' parts or geons) or with the holistic theories (which do not predict priming by ``shapeless'' location on its own). They may be interpreted in terms of a hybrid theory, according to which conjunctions of shape and location are explicitly represented, and therefore amenable to priming.

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