This 4-year longitudinal study of logical reasoning found complex interrelationships among different cognitive processes of children ages 6 to 15. Piaget's stage theory is discussed in the introduction, with a focus on the concrete operational stage in middle childhood. In the study, a representative array of logical concept tasks and short-term…

The impact of date of birth on cognitive test scores is well documented across many countries, with the youngest children in each academic year performing more poorly, on average, than the older members of their cohort (see, for example, Bedard and Dhuey (2006) or Puhani and Weber (2005)1). However, relatively little is known about the driving…