Human smile: Universal, innate, and cultural issues

The study of emotions and emotional face expressions has provoked increasing interest in contemporary researchers. Understanding the mechanisms of production, regulation and perception of the emotions, as well as of ontogenesis of the emotional expressions, has been considered central for the comprehension of infant development, in its cognitive, affective and social aspects. However, many questions related to the origins of these expressions still remain as subjects of controversies. Thus, babies' facial expressions of emotion are an important object of inquiry, including the ontogenesis of the smile. The aim of this work is to argue for a socio-cultural and evolutionary perspective for the study of the human smile, based on the discussion of literature on its innate and acquired aspects and its phylogenetic origins, enabling the formularization of hypotheses to be submitted to empirical test.