|The primary purposes of this study were to document the frequency and rate of affect expression for preschool children engaged in dyadic play, to determine the contextual constraints on such affect expression imposed by the child’s age, gender, and race/ethnicity, to contrast observed affect expression with teacher rated affect expression, and to examine relations between the several affect expression measures and measures of peer social competence. A total of 183 preschool children (84 females, 99 males) participated in this study. Analyses suggested that the expression of both positive and negative affect increased with age and that rates of affect expressivity were higher for
children from European-American backgrounds than from other race/ethnicity groups. Despite the mean differences associated with age and race/ethnicity, the patterns of association among variables and between sets of variables were not meaningfully different, indicating that the interpretation of affect expressiveness does not differ by age or race/ethnic status. Teachers’ ratings of child positive and negative affect had only modest associations with observed rates of affect expression; however, teachers’ ratings relevant to reactivity/regulation did show a moderately strong relation with observed negative affect expression. Analyses predicting measures of peer social competence from affect expression indicators showed that both positive and negative affect expression were related to sociometric acceptance scores and categories of peer interaction. For the teacher ratings of affect (but not observed expression of affect), significant associations with Q-sort measures of social competence were also obtained. Regression analyses using both observed affect expression and teacher-rated affect scores indicated that both sets had unique, significant associations with the social competence outcomes (although these varied across the social competence indicator set). The results are interpreted as evidence that affect expression is a salient feature of children’s experience in the preschool classroom. These results are consistent with interpretations of affect expression from positive psychology and from developmental theories of emotional competence.