Human-like pitch perception mechanisms in marmoset monkeys

The perception of the pitch of harmonic complex sounds is a crucial function of human audition, especially in music and speech processing. Whether the underlying mechanisms of pitch perception are unique to humans, however, is unknown. Based on estimates of frequency resolution at the level of the auditory periphery, psychoacoustic studies in humans have revealed several primary features of central pitch mechanisms. It has been shown that (1) the pitch strength of a harmonic tone is dominated by resolved harmonics; (2) pitch of resolved harmonics is sensitive to the quality of spectral harmonicity; and (3) pitch of unresolved harmonics is sensitive to the salience of temporal envelope cues. Here, we show that, for a standard musical tuning fundamental frequency of 440 Hz (ISO 16), the common marmoset (Callithrix jacchus), a New World monkey with a hearing range similar to that of humans, exhibits all the primary features of central pitch mechanisms demonstrated in humans. Thus, marmosets and humans may share similar pitch perception mechanisms, combined with previous findings of a specialized pitch processing region in both marmoset and human auditory cortex, suggesting that these mechanisms may have emerged early in primate evolution.