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 = 37, 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. (C) 2009 Elsevier Inc. All rights reserved.