Different types of smiles and laughter in preschool children.

The relationship among morphologically different forms of smiling and laughter was examined. The participants were 19 Brazilian preschool children. Each child was observed a total of 60 min. in three 10-min. sessions on the playground and three 10-min. sessions in the classroom. Analysis suggests that the various forms of smiling do not simply express different intensities of a single emotion. A two-dimensional structure was indicated by factorial analysis. The first dimension, which could be called playfulness-mock aggression, consisted of a broad smile and laughter. The second dimension, which could be called friendliness-appeasement, consisted of a closed and upper smile. The pattern of correlation found between expressive behaviors and both teacher's and peers' evaluations gives further support to the interpretation that smiling is an heterogeneous category.