A longitudinal study of within-individual variation in human voice pitch
Résumé
Individual differences in human voice pitch (fundamental frequency, F0) have evolutionary relevance. Fundamental frequency indicates the sex, age, and even dominance of the speaker, and influences a host of social assessments including mate preferences. Yet, due to the almost exclusive utilization of cross-sectional designs in previous work, it remains unknown whether individual differences in F0 emerge before or after sexual maturation, and whether F0 remains stable throughout a person’s lifetime. In our study, we tracked within-individual variation in the F0s of male and female speakers whose voices were recorded from childhood into adulthood. Voice recordings were extracted from digital archives. Our results corroborate those of earlier cross-sectional studies indicating a sharp decrease in male F0 at puberty resulting in the emergence of sexual dimorphism in adult F0. Critically, our results further revealed that men’s pre-pubertal F0 strongly predicted their F0 at every subsequent adult age, and that F0 remained remarkably stable within-individuals throughout their adulthood. These findings suggest that adult men’s voice pitch may be linked to pre-natal/pre-pubertal androgen exposure and may function as a reliable and stable signal of mate quality, with implications for our understanding of the developmental mechanisms, adaptive functions, and social perception of human voice pitch.