Genetic change and continuity from fourteen to twenty months: the MacArthur Longitudinal Twin Study.

Genetic change as well as continuity was investigated within the domains of temperament, emotion, and cognition/language for 200 pairs of twins assessed at 14 and 20 months of age in the laboratory and home. The second year of life is marked by change rather than continuity: correlations from 14 to 20 months averaged about .30 for observational measures of temperament and emotion, about .40 for language measures, and about .50 for mental development. 2 types of genetic change were examined: changes in the magnitude of genetic influence (heritability) and genetic contributions to change from 14 to 20 months. In general, heritability estimates were similar at 14 and 20 months. Evidence for genetic influence on change from 14 to 20 months emerged for several measures, implying that heritability cannot be equated with stability. Analyses of continuity indicated that genetic factors are largely responsible for continuity from 14 to 20 months.

Family-peer connections: the roles of emotional expressiveness within the family and children's understanding of emotions.

The purpose of this study was to explore patterns of parent and child emotional expressiveness within the family context, to examine links between these patterns and children's peer relations, and to examine whether these links might be mediated by children's understanding of emotions. Subjects were 61 kindergarten and first-grade white, middle-class children and their parents. Parent and child expressiveness were assessed in a laboratory ring-toss game designed to elicit a range of emotional responses. Parent expressiveness in the home was also assessed with Halberstadt's Family Expressiveness Questionnaire. The questionnaire, completed by both mother and father, assesses a range of emotions in a variety of settings typical of many families, and consists of items tapping both positive and negative expressiveness. Children were interviewed about their understanding of emotions across a broad range of areas. Results indicated that maternal expressiveness (home) and paternal expressiveness (home and laboratory) but not children's expressiveness with parents were associated with children's peer relations. Although children's understanding of emotions was generally not associated with family expressiveness, understanding predicted children's peer relations. In addition, children's understanding influenced the links between maternal expressiveness in the home and peer relations and between paternal expressiveness in the laboratory and peer relations. This pattern of results underscores the importance of the emotional climate of the family for the development of children's social relations with peers.

Are insecure-avoidant infants with extensive day-care experience less stressed by and more independent in the strange situation?

In order to test the hypothesis that elevated ratings of avoidance and classifications of insecure-avoidant attachments of infants with extensive infant day-care histories may be the result of the fact that children with routine experiences of separation are less stressed by, and more independent in, the Strange Situation than more traditionally reared infants, 2 groups of 12-month-old infants with insecure-avoidant attachments were compared on 2 behavioral indices in each reunion-with-mother episode of the Strange Situation. 9 infants experienced less than 20 hours per week of nonparental care in their first year, and 11 infants experienced 20 or more hours of care. Contrary to propositions advanced by Clarke-Stewart, Thompson, and others, insecure-avoidant infants with extensive nonparental care experience whimpered, fussed, and cried more and engaged in object play less in each reunion episode than their insecure-avoidant counterparts with less nonparental care experience. These results are discussed in terms of the recent controversy surrounding infant day-care in the United States.