Subconscious absolute pitch as a general trait
Before 2000 it was unknown that a precognitive version of absolute pitch is general in humans. This ability is subconsciously applied in speech and it can be considered as a further means of speaker identification, in addition to voice timbre.
Application of the precognitive, absolute pitch-memory increases with speech emphasis. This is neuroanatomically plausible, because the major precognitive command center for speech (in the anterior cingulate cortex) is not only linked to a pitch memory but also to centers for arousal and emotion.
The motivation dependent use of the absolute pitch-memory can be assumed
as one of the evolutionary foundations of song, and thus of music in
Braun, M. (2001) Speech mirrors norm-tones: Absolute pitch as a normal but precognitive trait. Acoust. Res. Lett. Online 2, 8590. Free Full text PDF at publisher, Nature Science Update, Wissenschaft Online, SPIEGEL ONLINE, ORF ON Science, NRC Handelsblad - Rotterdam
Braun, M. (2002) Absolute pitch in emphasized speech. Acoust. Res. Lett. Online 3, 77-82. Free Full text PDF at publisher
Recent results from colleagues: Anatomical
brain deficits in possessors of absolute pitch