Studies have reported an inverse association between language development and behavioral inhibition or shyness across childhood, but the direction of this association remains unclear. This study tested alternative hypotheses regarding this association in a large sample of toddlers. Data on behavioral inhibition and expressive and receptive…

Although some evidence indicates that even very young children engage in rudimentary forms of strategic behavior, the underlying mechanisms remain largely unknown. This study tested the hypothesis that uncertainty monitoring underlies such behaviors. Three-, four-, and five-year-old children ("N" = 88) completed a perceptual…

Three experiments (total N = 140) tested the hypothesis that 5-year-old children's membership in randomly assigned "minimal" groups would be sufficient to induce intergroup bias. Children were randomly assigned to groups and engaged in tasks involving judgments of unfamiliar in-group or out-group children. Despite an absence of information…

This study examines the prevalence, stability, and development of physical aggression, as reported by mothers and fathers, in a sample of children initially recruited at 12, 24, and 36 months (N=2,253) and in a subsample followed up 1 year later (n=271) in a cross-sequential design. Physical aggression occurred in 12-month-olds, but significantly…