Differentiation hypotheses concern changes in the structural organization of cognitive abilities that depend on the level of general intelligence (ability differentiation) or age (developmental differentiation). Part 1 of this article presents a review of the literature on ability and developmental differentiation effects in children, revealing…

This prospective study examined the developmental changes over time of adolescents diagnosed in toddlerhood with autism spectrum disorder and searched for child characteristics at toddlerhood that predict outcome at adolescence. The study included 65 participants who were divided into low cognitive (developmental quotient [less than] 85; N = 41)…

Background: Williams syndrome (WS) is associated with a distinct cognitive-behavioural phenotype including mild to moderate intellectual disability, visual-spatial deficits, hypersociability, inattention and anxiety. Researchers typically characterise samples of individuals with WS by their intellectual functioning and adaptive behaviour. Because…

Age-related change in processing speed has been linked directly to increases in reasoning as well as indirectly via increases in the capacity of working memory (WM). Most of the evidence linking change in speed to reasoning has come from cross-sectional research; in this article we present the findings from a 2½-year longitudinal study of 277 6-…

Background: Children with language impairment (LI) show heterogeneity in development. We tracked children from pre-school to middle childhood to characterize three developmental trajectories: resolving, persisting and emerging LI. Methods: We analyzed data from children identified as having preschool LI, or being at family risk of dyslexia,…

Neuroscientists have long believed that there are sensitive periods in development during which the effects of experience play a critical role. And developmental psychologists have argued for the importance of early experience in the first years of life as being critical for brain and behavioral development. Most of the neuroscience research…

The relations among various spatial and mathematics skills were assessed in a cross-sectional study of 854 children from kindergarten, third, and sixth grades (i.e., 5 to 13 years of age). Children completed a battery of spatial mathematics tests and their scores were submitted to exploratory factor analyses both within and across domains. In the…

This study contributes to the understanding of how early parenting interventions implemented in low- and middle-income countries during the first 2 years of children's lives are sustained longitudinally to promote cognitive skills in preschoolers. We employed path analytic procedures to examine 2 family processes--the quality of home stimulation…

Elevated levels of risky behavior in adolescence may signal developmental change in unconscious appraisal of risk. Yet, prior research examining adolescent risk judgment has used tasks that elicit conscious deliberation. The present study, in contrast, attempts to characterize age differences in (less conscious) intuitive impressions of risk.…

We studied developmental trends in 5 important reasoning tasks that are critical components of the operational definition of rational thinking. The tasks measured denominator neglect, belief bias, base rate sensitivity, resistance to framing, and the tendency toward otherside thinking. In addition to age, we examined 2 other individual difference…

We describe the cognitive profile in a complete national cohort of children with cerebral palsy (CP). One hundred and twenty-seven Icelandic children (67 females, 60 males) with CP, born between 1985 and 2000 and assessed between the ages of 4 and 6 years 6 months (mean age 5y 5mo, SD 6mo), were included in the study. IQ was measured using the…

This study describes the developmental function and cross-age pattern of individual differences in mental test behavior during the first 5 years of life. Accompanying the study are brief commentaries by Ina C. Uzgiris and Earl S. Schaefer and a reply by the authors. (JMB)

The relationship between children's cognitive developmental level, as assessed by Piagetian tasks, and their performance on measures of intellectual and neuropsychological functioning was studied. Eight female and 22 male children--ages 8 to 12 years (mean=10.3)--with negative electroencephalographs and neurologic screening and no history of brain…

Do stage-related patterns of early cognitive development reported for normally developing children also characterize at-risk and handicapped children when mental age organization of data is used? Mental age predicted Piagetian-based cognitive levels one to three but did not predict highest-level symbolic functioning in 95 handicapped children.…

Since early research had shown that a total score on 27 Piagetian tasks was very highly correlated with a Wechsler and achievement composite, a study investigated the possibility of shortening the Piagetian test by means of classical analysis methodology. (HOD)