Radiographic analysis of canine vocal tract anatomy and its implications for human language origins

Abstract

viii, 88 leaves ; 29 cmRadiographic images of the skull and vocal tract of adults from two canid species were analyzed for two studies addressing functional issues in animal communication and human language. Study 1 tested the hypothesis that vocal tract length scales reliably with overall body size such that the acoustic features of vocalizations influenced by vocal tract length can serve as honest cues to vocalizer body size. Results supported this hypothesis but emphasized that correlations with body size were better for oral cavity length than for pharyngeal cavity length. Study 2 tested the hypothesis that laryngeal position can vary in response to selection on cranio-facial size and shape. Results supported this hypothesis, finding that the larynx occupies a more descended position in the vocal tract of individuals with shorter, broader faces compared to longer, narrower faces. The latter findings have important implications for the origins and evolution of language in humans