Dissociable neural, subsystems underlie abstract and specific object recognition

Participants named objects presented in the left ol right visual field duri ng a test phase, after viewing centrally presented same-exemplar objects, d ifferent-exemplar objects, and words that name objects during an initial en coding phase. In two experiments, repetition priming was exemplar-abstract yet visual when test objects were presented directly to the left cerebral h emisphere, but exemplar-specific when test objects were presented directly to the right cerebral hemisphere, contrary to predictions from single-syste m theories of object recognition, In two other experiments, stimulus degrad ation during encoding and task demands during test modulated these results in predicted ways. The results slipper? the theory that dissociable neural subsystems operate in parallel (not ir? sequence) to underlie visual object recognition: An abstract-category subsystem operates more effectively than a specific-exemplar subsystem in the left hemisphere, and a specific-exemp lar subsystem operates more effectively than an abstract-category subsystem in the right hemisphere.