Abstract
Infants over one month of age tend to produce two types of smiling during especially positive social interactions, Duchenne smiles involving cheek raising and open‐mouth smiles. Little is known, however, about the prevalence, frequency, duration and organization of these smiles among neonates. Twenty‐five full‐term, healthy neonates (12 female) were videotaped during six minutes of sleep. Smiles were identified and analysed using an anatomically based coding system (FACS/Baby FACS). One‐half of the neonates showed bilateral Duchenne smiles. One‐quarter of the neonates showed bilateral Duchenne smiles at a mature level of intensity whose median duration was 1⅓ s. By contrast, open‐mouth bilateral smiles occurred in less than one‐tenth of the sample. The contrast between the more frequent bilateral Duchenne smiles and the less frequent open‐mouth smile is discussed in terms of the early synergistic functioning of facial muscles and contrasted with the smiling patterns of older infants.
