Shifting ear differences in melody comparison through transposition.

Nonmusicians were required to classify pairs of melodies as "same" or "different". When they were instructed to compare melodies played at the same pitch level as fast as possible, a REA was elicited. In contrast, a tendency in favor of the left ear came out when, all other things being equal, melodies were transposed, i.e. played at a different pitch level. Transposition was thus instrumental in leading subjects to rely more on right-hemisphere processing. Independent evidence for a change in the processing mode that was adopted with these two types of material was provided by the response times. The results indicated the use of a self-terminating process of analytic search only with the untransposed melodies. Results are discussed in terms of the notion that the preferential use of local or global properties in melodies determines the intervention of the left or the right cerebral hemisphere, respectively.