Scientific modeling (SM) is a core practice of science and an important component of scientific literacy. Supporting students in developing the competence to construct, use, evaluate, and revise models is hence of particular relevance. While research has shown that spatial visualization (SV), a core component of spatial ability, is correlated with…

Many children fail to master fraction arithmetic even after years of instruction. A recent theory of fraction arithmetic (Braithwaite, Pyke, & Siegler, 2017) hypothesized that this poor learning of fraction arithmetic procedures reflects poor conceptual understanding of them. To test this hypothesis, we performed three experiments examining…

Many children fail to master fraction arithmetic even after years of instruction. A recent theory of fraction arithmetic (Braithwaite, Pyke, & Siegler, in press) hypothesized that this poor learning of fraction arithmetic procedures reflects poor conceptual understanding of them. To test this hypothesis, we performed three experiments…

The developmental trajectory of the use of morphemes is still unclear. We investigated the emergence of morphological effects on visual word recognition in German in a large sample across the complete course of reading acquisition in elementary school. To this end, we analyzed lexical decision data on a total of 1,152 words and pseudowords from a…

Many people have serious difficulties in understanding rational numbers, limiting their ability to interpret and make use of them in modern daily life. This also leads to later difficulties in learning more advanced mathematical content. In this study, novel tasks are used to measure 263 late primary school students' spontaneous focusing on…

Children experience good and bad days in their performance. Although this phenomenon is well-known to teachers, parents, and students it has not been investigated empirically. We examined whether children's working memory performance varies systematically from day to day and to which extent fluctuations at faster timescales (i.e., occasions,…

We studied developmental trends in 5 important reasoning tasks that are critical components of the operational definition of rational thinking. The tasks measured denominator neglect, belief bias, base rate sensitivity, resistance to framing, and the tendency toward otherside thinking. In addition to age, we examined 2 other individual difference…