The acoustic origin of the smile

摘要: In many species, appeasement or submissive vocalizations have a high fundamental frequency in order that the sender may sound like an infant and thus elicit parental helping response from its would‐be antagonist [Morton, Am. Nat. 111, (1977)]. High vocal tract resonances also enhance infantile character of vocalization by seeming to originate shorter tract. Higher can be achieved trumpet‐like flaring and/or retracting corners mouth. This latter gesture, I hypothesize, is origin smile. Ritualization visual component this acoustically motivated gesture accounts for smile often being performed soundlessly man higher primates. The upshifting due mouth corner retraction was simulated using pulsed plasticine models tracts. Significantly, ethological literature documents widely found cross‐specific aggressive display involves constriction protrusio...