Fig. 1: Human vocal communication of body size.
From: Efficacy in deceptive vocal exaggeration of human body size
a Sagittal MRI image of human vocal anatomy illustrating vocal tract length (VTL) (in red) during production of the vowel /u:/, and permanently descended larynx housing the vocal folds (blue circle). Human VTL scales fairly allometrically with body size due to anatomical constraints, whereas vocal fold length does not26,28,32,33. b Resonances of the vocal tract termed formants (labelled F1–F4) and their relative spacing (∆F) inversely predict human height controlling for sex and age33,34, whereas fundamental frequency (labelled fo), related to vocal fold length, does not34. c Human listeners robustly associate both voice frequencies (low ∆F and fo) with large body size in regular speech25,36 and in nonverbal vocalisations (e.g., roars39), but can humans judge size from deceptive vocal signals? Panels a, b were reproduced and reformatted with permission21; parts of panel c were designed using resources from freepik.com and rawpixel.com (https://www.freepik.com/free-vector/illustration-business-people_2609966.htm#query=man%20black%20silhouette&position=17).
