title: THE SMILING RESPONSE TO THE HUMAN FACE. I. METHODOLOGY, QUANTIFICATION AND NATURAL HISTORY.
mesh_terms: D004644:Emotions; D005149:Facial Expression; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007845:Laughter; D012904:Smiling
keywords: EMOTIONS; FACIAL EXPRESSION; INFANT; INFANT, NEWBORN; LAUGHTER