Experts claim that individual differences in children's formal understanding of mathematical equivalence have consequences for mathematics achievement; however, evidence is lacking. A prospective, longitudinal study was conducted with a diverse sample of 112 children from a midsized city in the Midwestern United States (M[subscript age] [second…

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…

This book presents original, empirical data from quantitative and qualitative research studies in the field of language learning aptitude, ability, and individual differences. It does so from the perspectives of Second Language Acquisition, psychology, neuroscience and sociolinguistics. All studies included in the book use a similar and uniform…

Multilevel modeling was used to address the longitudinal stability of standard scores (SSs) measuring intellectual ability for children with Williams syndrome (WS). Participants were 40 children with genetically confirmed WS who completed the Kaufman Brief Intelligence Test--Second Edition (KBIT-2; A. S. Kaufman & N. L. Kaufman, 2004) 4-7…

Background: The international literature has documented that self-determination is impacted by environmental factors, including living or work settings; and by intraindividual factors, including intelligence level, age, gender, social skills and adaptive behaviour. In addition, self-determination has been correlated with improved quality of life…