Background: Intra-individual variability reflects temporal variation within an individual's performance on a cognitive task. Children with developmental disorders, such as ADHD and ASD show increased levels of intra-individual variability. In typical development, intra-individual variability decreases sharply between the ages 6 and 20. The tight…

Background: We assessed trajectories of children's internalizing symptoms as predicted by interactions among maternal internalizing symptoms, respiratory sinus arrhythmia (RSA) and child sex. Method: An ethnically and socioeconomically diverse sample of children (n = 251) participated during three study waves. Children's mean ages were 8.23 years…

Background: If the adaptive significance of specific fears changes with age, the genetic contribution to individual differences may be lowest at the age of greatest salience. The roles of genes and environment in the developmental-genetic trajectory of five common childhood fears are explored in 1094 like-sex pairs of male and female monozygotic…

Background: Childhood psychopathology is associated with both high and low levels of prosocial behaviour. It has been proposed that the development of prosocial behaviour shows emerging and consolidating individual differences as children grow older. The influences on these individual differences have not previously been examined in children and…

Background: The present study extends existing studies on the role of differential parental treatment in explaining individual differences in adolescent problem behaviors above the absolute level of parenting and clarifies the function of gender of the child, birth rank and gender constellation of the sibling dyads. Method: The absolute level of…