Sexual Selection on Human Voice Pitch: Cross-species, Cross-cultural, Experimental, and Naturalistic Investigations
Restricted (Penn State Only)
- Author:
- Aung, Toe
- Graduate Program:
- Anthropology
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- July 29, 2022
- Committee Members:
- David Puts, Chair & Dissertation Advisor
Mary Katherine Shenk, Professor in Charge/Director of Graduate Studies
Mark Shriver, Major Field Member
Mary Shenk, Major Field Member
Reginald Adams, Outside Unit & Field Member - Keywords:
- cross-species
cross-cultural
formidability
fundamental frequency
voice pitch
attractiveness
cross-species
cross-cultural
formidability
fundamental frequency
voice pitch
attractiveness
cross-species
cross-cultural
formidability
fundamental frequency
voice pitch
attractiveness
sexual selection - Abstract:
- This dissertation is comprised of 5 studies, with vocalization data from cross-species, cross-cultural, meta-analytic, experimental, and naturalistic contexts. Study 1 explores why sex differences in vocal fundamental frequency (fo; perceived as pitch) evolve across species including humans; Study 2 examines what socioecological factors moderate the influence of voice pitch on our social perceptions; and Studies 3-5 examine what human voice pitch signals to listeners, and why it influences our perceptions. Study 1 utilizes a large sample of vocalizations (n = 2,129 recordings) across 56 anthropoid primate species. Controlling for phylogeny and body size dimorphism, the study examined whether fo dimorphism in primates evolved in response to increased mating competition intensity, a trade-off against sperm competition level, large complex social organizations, and poor acoustic environments. Results indicate that sexual dimorphism in fo increased in evolutionary transitions toward larger group size and a more female-biased sex ratio. Deep male vocalizations in primates may be driven by sexual selection to win mating opportunities and may be more important in larger groups where social knowledge is limited. Study 2 is a pre-registered voice experiment, involving 3,173 participants from 22 nations to test the robustness of previously demonstrated links between fo and social perceptions in diverse cross-cultural samples and to identify socioecological predictors that explain cross-cultural variation in the magnitude of fo preferences on social perceptions. Low male fo increased men’s perceptions of formidability and prestige especially in societies with higher relational mobility, where rapid identification of high-status competitors may be exigent, and in societies with higher homicide rates, where male intrasexual competition may be more intense. Results also indicate that lower societal health and food security and higher historical pathogen prevalence weakened women’s preferences for low male fo in short-term mating contexts, challenging the hypothesis that female preferences for male traits function to recruit heritable immunocompetence for offspring. Overall findings suggest that low male fo may have evolved primarily in the context of male contest competition rather than female mate choice. Study 3 comprises an in-depth literature review by integrating evidence associated with fo and formidability, clarifying theoretical expectations about the strength of the relationship between fo and formidability, and resolving issues on why a much stronger experimental effect of fo on perceived formidability is often observed. Additionally, Study 3 presents meta-analyses linking lower pitch to higher testosterone (total n = 763) and upper-body strength (total n = 845). A statistical demonstration that voice pitch conveys information would involve mediation analyses showing that voice pitch mediates a relationship between speaker characteristics and listener perceptions. Study 4 used two datasets from the United States (n = 231 male speakers, 565 male raters) and Canada (n = 74 male speakers, 108 female raters, and 65 male raters) to test whether male fo provides useful information about developmental condition. Male fo mediated the relationship between an objective measure of developmental condition (height) and perceived formidability (judgements of height and physical dominance from voice recordings). Lastly, Study 5 tests whether fo and other acoustic measures predict fighting ability in a large sample of professional mixed martial arts fighters, circumventing ethical concerns preventing past researchers from examining relationships between fo and actual fighting ability. Male voice pitch and vocal timbre negatively predicted “Fighting Experience” and “Size” factor scores in a multivariate regression model, explaining 3-8% of the variance, suggesting that lower male pitch and formants may be valid cues of some components of fighting ability in men.