This study examines the extent to which iron deficiency in infancy contributes to adverse neurocognitive and educational outcomes in young adulthood directly and indirectly, through its influence on verbal cognition and attention problems in childhood. Young adults (N = 1,000, M age = 21.3 years, 52% female; of Spanish or indigenous descent) from…

A large-scale ("N" = 552) controlled multivariate prospective 14-year longitudinal study of a developmental cascade embedded in a developmental system showed that information-processing efficiency in infancy (4 months), general mental development in toddlerhood (18 months), behavior difficulties in early childhood (36 months),…

The Cognitive Proficiency Index (CPI) developed for the most recent Wechsler intelligence scales comprises the working memory and processing speed subtests. It reflects the proficiency and efficiency of cognitive processing and provides another lens for analyzing children's abilities assessed by the Wechsler Intelligence Scale for Children--Fourth…

This study explored the cognitive performance of children with Attention Deficit/Hyperactivity Disorder (ADHD) and/or Developmental Coordination Disorder (DCD) using the Wechsler Intelligence Scale for Children-IV. Participants were 62 children with ages between 9 years 8 months and 12 years 7 months. These children were placed into one of the…

The Wechsler Intelligence Scale for Children--Fourth Edition (WISC-IV; D. Wechsler, 2003a) is often utilized to assess children with traumatic brain injury (TBI), although little information is available regarding its psychometric properties in these children. The current study examined WISC-IV performance in a sample of 61 children with TBI. As…

The relationship between consistency of hand preference, left hemispheric specialization, and cognitive functioning was examined in an ongoing longitudinal investigation. Children were classified as consistent or inconsistent in their hand preference across 5 assessments from ages 18 to 42 months. Findings demonstrated that (a) this early…

Background: Previous research with earlier versions of the WISC and WAIS has demonstrated that when administered to people who have intellectual disabilities, the WAIS produced higher IQ scores than the WISC. The aim of this study was to examine whether these differences still exist. A comparison of the Wechsler Adult Intelligence Scale-Third…

Background: Little is known about executive functions among unaffected siblings of children with attention deficit/hyperactivity disorder (ADHD), and there is lack of such information from non-Western countries. We examined verbal and nonverbal executive functions in adolescents with ADHD, unaffected siblings and controls to test whether executive…

Background: The underlying mechanism of time perception deficit in long time intervals in attention-deficit/hyperactivity disorder (ADHD) is still unclear. This study used the time reproduction dual task to explore the role of the attentional resource in time perception deficits among children and adolescents with ADHD. Methods: Participants…

Background: Recent reports showed that children born with intrauterine growth restriction (IUGR) are at greater risk of experiencing verbal short-term memory span (STM) deficits that may impede their learning capacities at school. It is still unknown whether these deficits are modality dependent. Methods: This long-term, prospective design study…

A set of 5 reaction time tests of increasing cognitive complexity were administered to 35 secondary school pupils in Zimbabwe and The Netherlands at 4 consecutive school days in order to explore the existence and nature of cross-cultural differences on reaction time tests measuring basic cognitive operations. No cross-cultural differences were…

Examined the assumption that Spearman's law acts unsystematically and approximately uniformly for various subtests of cognitive ability in an IQ test battery when high- and low-ability IQ groups are selected. Data from national standardization samples for Wechsler adult and child IQ tests affirm regularities in Spearman's "Law of Diminishing…

An intelligence test and several oral reading tasks were administered to 87 post-kindergarten children (mean age of six years, four months) with high achievement ratings to describe the cognitive correlates of precocious reading achievement. The structure of individual differences in reading subskill patterns compatible with precocity were also…

Children aged 6 to 13 years were given verbal and nonverbal fluency tasks and block design subtests of the Wechsler Intelligence Scale for Children-Revised. Results, providing normative data, showed that fluency tasks are age-, but not sex-dependent, and are modestly correlated to one another. (Author/CM)

The differences between learning disabled (LD) and non-LD children's problem-solving protocols were analyzed during a picture arrangement task. Although the groups of 29 LD and 27 non-LD children were comparable in global mental processing and task performance, LD children had difficulty with representing problems and deleting irrelevant…