Voice disadvantage effects in absolute and relative pitch judgments.

Absolute pitch (AP) possessors can identify musical notes without an external reference. Most AP studies have used musical instruments and pure tones for testing, rather than the human voice. However, the voice is crucial for human communication in both speech and music, and evidence for voice-specific neural processing mechanisms and brain regions suggests that AP processing of voice may be different. Here, musicians with AP or relative pitch (RP) completed online AP or RP note-naming tasks, respectively. Four synthetic sound categories were tested: voice, viola, simplified voice, and simplified viola. Simplified sounds had the same long-term spectral information but no temporal fluctuations (such as vibrato). The AP group was less accurate in judging the note names for voice than for viola in both the original and simplified conditions. A smaller, marginally significant effect was observed in the RP group. A voice disadvantage effect was also observed in a simple pitch discrimination task, even with simplified stimuli. To reconcile these results with voice-advantage effects in other domains, it is proposed that voices are processed in a way that voice- or speech-relevant features are facilitated at the expense of features that are less relevant to voice processing, such as fine-grained pitch information.