Vocal aging effects on F ⁰ and the first formant: A longitudinal analysis in adult speakers

This paper presents a longitudinal analysis of the extent to which age affects F ⁰ and formant frequencies. Five speakers at two time intervals showed a clear effect for F ⁰ and F1 but no systematic effects for F ² or F ³. In two speakers for which recordings were available in successive years over a 50 year period, results showed with increasing age a decrease in both F ⁰ and F1 for a female speaker and a V-shaped pattern, i.e. a decrease followed by an increase in both F ⁰ and F1 for a male speaker. This analysis also provided strong evidence that F1 approximately tracked F ⁰ across the years: i.e., the rate of change of (the logarithm of) F ⁰ and F1 were generally the same. We then also tested that the changes in F1 were not an acoustic artifact of changing F ⁰. Perception experiments with the main aim of assessing whether changes in F1 contributed to age judgments beyond those from F ⁰ showed that the contribution of F1 was inconsistent and negligible. The general conclusion is that age-related changes in F1 may be compensatory to offset a physiologically induced decline in F ⁰ and thereby maintain a relatively constant auditory distance between F ⁰ and F1.