Young children have informal knowledge of fractions before learning about fraction symbols in school. In the current study, we followed 103 children in the Mid-Atlantic United States from the fall to the spring of first grade to characterize the development of individual differences in early informal fraction knowledge, as well as its relation to…

This study aim to determine early clues that can be seen in kindergarten students at risk of dyslexia. The sample consisted of 27 students selected from two kindergartens through purposeful sampling. The Kindergarten Dyslexia Pre-Determination Observation Form was developed by researcher, Personal Information Form and Colorado Learning Disability…

Longitudinal associations of domain-general and numerical competencies with individual differences in children's understanding of fractions were investigated. Children (n = 163) were assessed at 6 years of age on domain-general (nonverbal reasoning, language, attentive behavior, executive control, visual-spatial memory) and numerical (number…

Lateralization of the brain is strongly influenced by prenatal androgens, with differential exposure thought to account for cognitive sex differences. This study investigated sex and individual differences and relationships between 2D:4D (the ratio of the 2nd to 4th digit [digit ratio] as a proxy indicator of prenatal testosterone exposure),…

Arithmetic and cognitive skills of children with mathematical difficulties (MD-only), with comorbid reading difficulties (MD-RD), with reading difficulties (RD-only), and normally achieving children were examined at 3 points from Grades 3-4 to Grades 5-6 (age range, 9-13 years). Both MD groups displayed severe weaknesses in 4 domain-specific…

Passive and active visuospatial working memory (VSWM) were investigated in relation to maths performance. The mental rotation task was employed as a measure of active VSWM whereas passive VSWM was investigated using a modified Corsi Blocks task and a matrix pattern task. The Raven Progressive Matrices Test measured fluid intelligence. A total of…

The present study focuses on math and related skills among 32 girls with fragile X (n = 14) or Turner (n = 18) syndrome during late elementary school. Performance in each syndrome group was assessed relative to Full Scale IQ-matched comparison groups of girls from the general population (n = 32 and n = 89 for fragile X syndrome and Turner…

This paper reports the results of four dual-task experiments that were designed to determine the extent of domain-specificity of the verbal working memory resources used in linguistic integrations. To address this question, syntactic complexity was crossed in a 2x2 design with the complexity of a secondary task, which involved either (1)…

Compared performance of 9-year-olds with arithmetic difficulties to that of age-matched and ability-matched controls on 10 tasks used to assess different aspects of working memory, including subtypes of executive function. Found deficits in executive and spatial aspects of working memory that seem likely to be important factors in poor…

Gender differences in level and pattern of cognitive abilities were examined in 49 learning-disabled college students. Females were stronger in visual-motor abilities and verbal conceptualization, whereas the males' highest abilities were nonverbal visual-spatial. Both groups showed weaknesses in memory for digits and factual knowledge and in…