Children's lexical processing speed at 18 to 25 months of age has been linked to concurrent and later language abilities. In the current study, we extend this finding to children aged 36 months. Children (N = 126) participated in a lexical processing task in which they viewed two static images on noun trials (e.g., an ear of corn and a hat), or…

Purpose: Variability in the timing of infant developmental milestones is poorly understood. We used a twin analysis to estimate genetic and environmental influences on motor development and activity levels in infancy. Method: Data were from the Gemini Study, a twin birth cohort of 2,402 families with twins born in the United Kingdom in 2007.…

Despite implications that stranger fear is an important aspect of developing behavioral inhibition, a known risk factor for anxiety, normative and atypical developmental trajectories of stranger fear across infancy and toddlerhood remain understudied. We used a large, longitudinal data set (N = 1285) including multi-trait, multi-method assessments…

This study examined contributions of maternal personality and infant temperament to infant vocabulary and cognitive development both directly and indirectly through parental stress. Participants were recruited at birth and included 63 infant twin pairs and their mothers. Assessments were completed at 6, 9, 12, and 18 months of age and included…

Observational measures of monozygotic and dizygotic twins' reactions to simulations of distress in others were obtained when the twins were 14 and 20 months old. Components of concern for others increased with age. Girls scored higher than boys on most measures. There was modest evidence for heritability of empathy. (BC)

Analyzed 20 test items for evidence of concordance for samples that included at least 120 pairs of identical twins and 85 pairs of same-sex fraternal twins at ages 3, 6, 9 and 12 months. Also computed within-pair correlations for the total number of Piagetian-equivalent items passed. (Author/SDH)

This study investigated associations between selected infant and maternal characteristics and autism risk in 4381 California children with autism. Increased risk factors were observed for males, multiple births, and children born to black mothers. Risk increased as maternal age and maternal education increased. Children of immigrant mothers had…

The explosion in the rate of multiple births has led to new questions about how adequately prepared parents are for the demands of raising triplets and the implications for the healthy development of the infants. The authors examined the relationship between mothering, infant social behavior, and cognitive development in a longitudinal study of 23…