Скачать или смотреть Why Do We Show Our Teeth When We Smile? | Evolution of Smiling

Many animals show their teeth when they are aggressive, but in humans showing teeth while smiling is a friendly and happy emotion. How did this evolve?

Whereas facial expression and emotional expressions are important in all mammals, they are the most developed in primates. Whereas showing teeth and growling is a relatively simple sign of aggression in other animals, primates have a variety of emotional expressions where they show teeth. Subtle differences between facial expression can relate to different emotional states.

Showing teeth in primates can be a sign of aggression, when the lips are curled backwards. But when primates show their teeth, holding them together and having relaxed lips it is more a sign of submission. This subtle difference may have evolved over time and was accelerated by play fights. In play fights primates fake their emotional states to train for real confrontations. Subtle differences in facial expression however show the sparring partner that the aggression is not real.

References/resources:
Bax, J.S., Ungar, P.S. (1999). Incisor labial surface wear striations in modern humans and their implications for handedness in Middle and Late Pleistocene hominids. Internationa Journal of Osteoarcheology, 9(3), 189-198.

Caron, James E. (2002). From ethology to aesthetics: Evolution as a theoretical paradigm for research on laughter, humor, and other comic phenomena. Humor - International Journal of Humor Research, 15(3), –. doi:10.1515/humr.2002.015

Clement, A. F., Hillson, S. W., & Aiello, L. C. (2012). Tooth wear, Neanderthal facial morphology and the anterior dental loading hypothesis. Journal of human evolution, 62(3), 367–376. https://doi.org/10.1016/j.jhevol.2011...

Davila-Ross, M., & Dezecache, G. (2021). The Complexity and Phylogenetic Continuity of Laughter and Smiles in Hominids. Frontiers in psychology, 12, 648497. https://doi.org/10.3389/fpsyg.2021.64...

Petersen, R.M., Higham, J.P. The Role of Sexual Selection in the Evolution of Facial Displays in Male Non-human Primates and Men. Adaptive Human Behavior and Physiology 6, 249–276 (2020). https://doi.org/10.1007/s40750-020-00...

Porteous J.(1989). Philosophy and Humor || Humor and Social Life. Philosophy East and West, 39(3), 279–288. doi:10.2307/1399449

Narrated by: Miles Wischnewski

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