Real-Time Probing of Modulations in South Indian Classical (Carnātic) Music by Indian and Western Musicians

We used Toiviainen and Krumhansl’s (2003) concurrent probe-tone technique to track Indian and Western musicians’ tonal-hierarchy profiles through modulations in Carnātic (South Indian classical) music. Changes of mode (rāgam) are particularly interesting in Carnātic music because of the large number of modes (more than 300) in its tonal system. We first had musicians generate profiles to establish a baseline for each of four rāgams in isolation. Then we obtained dynamic profiles of two modulating excerpts, each of which incorporated two of the four baseline rāgams. The two excerpts used the two techniques of modulation in Carnātic music: grahabēdham (analogous to a Western shift from C major to A minor), and rāgamālikā (analogous to a shift from C major to C minor). We assessed listeners’ tracking of the modulations by plotting the correlations of their response profiles with the baseline profiles. In general, the correlation to the original rāgam declined and the correlation to the new rāgam increased with the modulation, and then followed the reverse pattern when the original rāgam returned. Westerners’ responses matched those of the Indians on rāgams with structures similar to Western scales, but differed when rāgams were less familiar, and surprisingly, they registered the shifts more strongly than Indian musicians. These findings converged with previous research in identifying three types of cues: 1) culture-specific cues—schematic and veridical knowledge—employed by Indians, 2) tone-distribution cues—duration and frequency of note occurrence—employed by both Indians and Westerners, and 3) transference of schematic knowledge of Western music by Western participants.