Voice change as a new measure of male pubertal timing: A study among Bolivian adolescents

Background: Age at menarche is often used to measure maturational tempo in girls. Unfortunately, no parallel marker exists for boys. It is suggested that voice change has a number of advantages as a marker of the timing and degree of male pubertal development. Aim: Traditional auxological methods are applied to voice change in order to compare differential development both between (males vs females; Tsimane vs North American; better vs worse condition) and within (voice vs height; fundamental frequency vs formant structure) populations. Subjects and methods: Fundamental and formant frequencies, as well as height and weight, were measured for 172 Tsimane males and females, aged 8–23. Participants were assigned to ‘better ’ or ‘worse ’ condition based on a median split of height-for-age and weight-for-age z-scores. Results: Results support dramatic vocal changes in males. Peak voice change among Tsimane male adolescents occurs, 1 year later than in an age-matched North American sample. Achieved adult male voices are also higher in the Tsimane. Tsimane males in worse condition experience voice change more than 1 year later than Tsimane males in better condition. Conclusion: Voice change has a number of attractive features as a marker of male pubertal timing including its methodological and technical simplicity as well as its social salience to group members