Analytic processing in the classification of melodies as same or different.

Two groups of non-musicians were required to classify pairs of melodies as "same" or "different". The experimental group was instructed to respond as fast as possible, while the control group did not receive such a speed requirement. Contrary to the control subjects, the experimental subjects exhibited a right-ear advantage in accuracy for "different" responses. Thus, time pressure was instrumental in inducing subjects to rely mainly on left-hemisphere processing. The fact that "different" responses were both faster than "same" ones and quicker than melody offset indicates the use of a self-terminating search process. The features searched for were, in all likelihood, local. Indeed, contrary to control subjects, experimental subjects performed equally well with (1) melodies differing in both contour and local pitches and with (2) melodies differing in local pitches only.