Differential sensitivity to pitch distance, particularly in speech.

The fundamental frequency in speech shows many rapid variations, part of which determine the perceived shape of the pitch contour. This implies that the accuracy with which listeners perceive changes of F0 is more relevant to understanding the perception of intonation than the traditional just noticeable difference of F0 in speech. This study examines the sensitivity to differences in the amount of change of F0, upward (Experiment Ia) and downward (Experiment Ib). Subjects 74 and 104, respectively, with widely different musical ability can be divided into three categories: (1) Quite a number of them were not able to discriminate differences of less than 4 semitones (nondiscriminators); (2) other subjects wrongly tried to base their judgments on a simple comparison of the final pitches of a stimulus pair (final pitch discriminators); (3) the remaining subjects (pitch distance discriminators) yielded average jnd's of about 1.5 to 2 semitones. Since the issue is associated with musical interval sense, similar experiments were carried out using piano tones. The results were essentially the same as with the speech stimuli. The outcome suggests that only differences of more than 3 semitones play a part in communicative situations.