Expression facial primate

Two video cameras Provision-Isr were used to film the monkeys continuously. Correspondence should be addressed to Lisa A. Therefore, in order to understand the evolution of human emotional expressions, like the smile, it is extremely informative to take a comparative approach and evaluate whether the form and function of these expressions are uniquely human, present in many related species, or perhaps only shared by very closely related species, like Hominoids Fridlund, Highly similar results were obtained for the eyes and eyebrows. Waller B, Dunbar RIM. Intramuscular electrical stimulation of facial muscles in humans and chimpanzees:

As infants develop, they more often initiate bouts of smiling Cohn and Tronick, Another possibility is that infant signals of need are exploitative, or represent the outcome of sibling conflict Godfray and Johnstone, Extensive variation both among and within facial expression phenotypes clearly requires multiple adaptive explanations, rather than a single hypothesis of facial expression.