The incremental validity of specific cognitive abilities beyond general intelligence has been investigated in studies using hierarchical multiple regression analyzes (HMR). In the present study, we investigated whether the incremental validity of specific cognitive abilities (i.e., verbal, figural, and numerical ability) for the explanation of…

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…

The old myth about the ability and variability of potential in children is a comforting myth, for those who are uneasy with the degree of inequality they see and would rather seek to justify it than confront it. The myth of inherent potential helps some explain to themselves why they are privileged. Extend the myth to believe in inherited ability…

The aim of the present study was to investigate the associations between elementary school children's mathematical achievement and their conservation abilities, visuospatial skills, and numerosity processing speed. We also assessed differences in these abilities between children with different types of learning problems. In Study 1 (N = 229), we…

The purpose of this study was to illustrate the use of the randomization test for single-case research designs (SCR; Kratochwill & Levin, 2010). To demonstrate the application of this approach, a systematic replication of Grünke, Wilbert, and Calder Stegemann (2013) was conducted to evaluate the effects of a story map to improve the reading…

Evidence from a large-scale study of 11-year olds in Britain suggests that ambidextrous individuals may be disadvantaged in tests of verbal, nonverbal, reading, and mathematical skills relative to right- and left-handers, but this basic finding was not replicated in another study of younger boys in Germany. Here, we present data based on a…

Criticizes and examines the motives behind Charles Murray's "The Bell Curve." Murray's book claimed that many social problems, including crime and poverty among blacks, could be explained by African Americans' lack of intelligence as evidenced by testing. Reveals the book's skewed methodology as well as its interest-guided financial…