Hemispheric differences in the recognition of environmental sounds.

Recent work has found support for two dissociable and parallel neural subsystems underlying object and shape recognition in the visual domain: an abstract-category subsystem that operates more effectively in the left cerebral hemisphere than in the right, and a specific-exemplar subsystem that operates more effectively in the right hemisphere than in the left. Evidence of this asymmetry has been observed for linguistic stimuli (words, pseudoword forms) and nonlinguistic stimuli (objects). In the auditory domain, we previously found hemispheric asymmetries in priming effects using linguistic stimuli (spoken words). In the present study, we conducted four long-term repetition-priming experiments to investigate whether such hemispheric asymmetries would be observed for nonlinguistic auditory stimuli (environmental sounds) as well. The results support the dissociable-subsystems theory. Specificity effects were obtained when sounds were presented to the left ear (right hemisphere), but not when sounds were presented to the right ear (left hemisphere). Theoretical implications are discussed.