The ontogenesis of smiling and its association with mothers’ affective behaviors: A longitudinal study

Two babies were observed from their third week to their sixth month of life. Our goals in the study were: to investigate developmental changes in smiling patterns; to analyze the smiling patterns observed in the presence of mother's affective behaviors, and to verify whether the babies can answer contingently, with smiles, to mothers’ affective behaviors. The babies and their mothers were videotaped at home. It was verified a positive linear trajectory tendency for the babies’ smiles. The babies revealed a particular tendency to display one or two kinds of smiles. Babies answered contingently with smiles to their mothers’ affective behaviors. Correlations between the most frequent types of babies’ smiles and his/her mothers’ smiles were verified (r = .77, p < .0017 – baby1, and r = .62, p < .0017 – baby2). Different types of smiles were exhibited by the babies as contingent answers to mothers’ behaviors. The results show an association between babies’ smiles and their mothers’ affective behaviors.