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…

Previous research findings indicate that young children from East Asia outperform their counterparts from Europe and North America on executive function (EF) tasks. However, very few cross-national studies have focused on EF development during middle childhood. The current study assessed the EF performance of 170 children in grades 2 and 4 from…

In contrast to classical phonological span tasks, which require verbal recall, those used in self-reliant, group-administrable working memory measurement contain a visuospatial response format. As a consequence, these tasks involve recoding, executive, and visual search requirements in addition to encoding and storage processes. To examine…

The reluctance of children to revise their prior beliefs is a prominent phenomenon in the reasoning literature. One way to facilitate belief change is offering explanations, and this study examined whether highlighting (counter) evidence with diagrams leads to belief revision to the same extent. Altogether 134 preschoolers and second-graders (5-…

In a series of 3 experiments, the authors investigated the influence of symmetry of variables on children's and adults' data interpretation. They hypothesized that symmetrical (i.e., present/present) variables would support correct interpretations more than asymmetrical (i.e., present/absent) variables. Participants were asked to judge covariation…

Children's estimation skills on a bounded and unbounded number line task were assessed in the light of their familiarity with numbers. Kindergartners, first graders, and second graders (N = 120) estimated the position of numbers on a 1--100 number line, marked with either two reference points (i.e., 1 and 10: unbounded condition) or three…

We investigated how letter length, phoneme length, and consonant clusters contribute to the word length effect in 2nd- and 4th-grade children. They read words from three different conditions: In one condition, letter length increased but phoneme length did not due to multiletter graphemes (H"aus"-B"auch"-S"chach"). In…

This article presents a reanalysis of the data of 862 second and fourth graders collected in two previous studies, focusing on the influence of method (psychometric vs. chronometric) and stimulus type on the gender difference in mental-rotation accuracy. The children had to solve mental-rotation tasks with animal pictures, letters, or cube…

In the course of elementary school, children start to develop an academic self-concept reflecting their motivation, thoughts, and feelings about a specific domain. For the domain of mathematics, gender differences can emerge which are characterized by a less pronounced math self-concept for girls. However, studies are rather sparse regarding the…

In a cross-sectional study, we examined the relationship between the quality of lexical representations and text comprehension skill in German primary school children (Grades 1-4). We measured the efficiency and accuracy of orthographical, phonological, and meaning representations by means of computerized tests. Text comprehension skill was…