MHC Heterozygosity predicts height but not vocal fundamental or formant frequencies in men and women

Vocal fundamental and formant frequencies influence basic human social perceptions, including attractiveness, yet it remains unresolved what information these acoustic parameters convey about a vocalizer. A prominent hypothesis is that conspicuous secondary sex traits such as fundamental and formant frequencies reflect heritable health and immune function, though evidence for this hypothesis is mixed. We investigated associations between these acoustic parameters, growth, and heterozygosity at MHC loci, a genetic indicator of immune function, in three samples of Canadian and U.S. young adults (N = 903). We tested whether fundamental and formant frequencies exhibit expected patterns of variability for sexually selected traits and whether these vocal characteristics are associated with MHC heterozygosity while assessing their links to growth. We found no relationship between MHC heterozygosity and fundamental or formant frequencies. Although fundamental frequency was negatively correlated with growth, this correlation did not vary significantly by sex, and fundamental frequency was more variable in females than males, whereas variation in formants did not differ by sex. These findings do not support the notion that voice pitch is a cue of immunocompetence and invite continued research into the information content of these socially salient acoustic parameters.