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�…