Whereas voice pitch is strongly linked to people's perceptions in contexts of sexual selection, such as attractiveness and dominance, evidence that links voice pitch to actual behaviour or the formidability of a speaker is sparse and mixed. In this registered report, we investigated how male speakers’ voice pitch is linked to fighting success in a dataset comprising 135 (amateur) mixed martial arts and 189 (amateur) boxing fights. Based on the assumption that voice pitch is an honest signal of formidability, we expected lower voice pitch to be linked to higher fighting success. The results indicated no significant relation between a fighter's voice pitch, as directly measured before a fight, and successive fighting success in both mixed martial arts fighters and boxers.

Voters are more likely to support candidates whose faces and voices are perceived as competent. However, what is the simultaneous influence of these two characteristics? Here this question is examined with an observational study and an experiment. In the observational study, subjects rated the facial competence of Members of the U.S. House of Representatives. The most and least competent faces identified were paired with recordings of competent (i.e., lower pitched) and incompetent (i.e., higher pitched) voices to create simulated candidates. For the experiment, a separate set of subjects voted between randomly generated pairs of these simulated candidates. The results show that candidates with competent faces or competent voices won more votes, but the influence of facial competence was nearly three times that of vocal competence.