Federico Fantoni, Veronica Maglieri, Nicolò Giusti, Chiara Scopa, Virginia Pallante, Antonio Lorenzo Loprete, Elisabetta Palagi
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引用次数: 0
Abstract
Facial communication regulates many aspects of social life in human and nonhuman primates. Empirically identifying distinct facial expressions and their underlying functions can help illuminate the evolution of species' communicative complexity. We focused on bared-teeth faces (BTFs), a highly versatile facial expression in the tolerant macaque Macaca tonkeana. By employing a diverse array of techniques (MaqFACS, unsupervised cluster analysis, Levenshtein distance, NetFACS), we quantitatively discriminated two distinct BTFs: bared-teeth (BT) and open mouth bared-teeth (OMBT), and evaluated their distribution across peaceful, playful, and agonistic contexts. Neither BT nor OMBT were context-specific, although BT frequently occurred during peaceful interactions and with low levels of stereotypy. OMBT was highly stereotyped during play, a context involving strong unpredictability. The presence of tongue-protrusion during OMBT was exclusive to peaceful contexts whereas the presence of glabella-lowering during BT and OMBT was specific to agonistic contexts. Hence, BT and OMBT per se are not context-specific, but their contextual relevance hinges on the inclusion of specific key elements. Moving forward, concurrent analyses of stereotypy and specificity should extend beyond our study to encompass other primate and non-primate species, facilitating direct comparisons and revealing how communicative and social complexity coevolve.
期刊介绍:
The objective of the American Journal of Primatology is to provide a forum for the exchange of ideas and findings among primatologists and to convey our increasing understanding of this order of animals to specialists and interested readers alike.
Primatology is an unusual science in that its practitioners work in a wide variety of departments and institutions, live in countries throughout the world, and carry out a vast range of research procedures. Whether we are anthropologists, psychologists, biologists, or medical researchers, whether we live in Japan, Kenya, Brazil, or the United States, whether we conduct naturalistic observations in the field or experiments in the lab, we are united in our goal of better understanding primates. Our studies of nonhuman primates are of interest to scientists in many other disciplines ranging from entomology to sociology.