Third, fifth, and seventh graders selected the best strategy (rounding up or rounding down) for estimating answers to two-digit addition problems. Executive function measures were collected for each individual. Data showed that (a) children's skill at both strategy selection and execution improved with age and (b) increased efficiency in executive…

Kindergarten to third grade mathematics achievement scores from a prospective study of mathematical development (n = 306) were subjected to latent growth trajectory analyses. The four corresponding classes included children with mathematical learning disability (MLD, 6% of sample), and low (LA, 50%), typically (TA, 39%) and high (HA, 5%) achieving…

Children in third and fourth grades suffering from developmental dyscalculia (DD) and typically developing children were asked to compare numbers to a standard. In two separate blocks, they were asked to compare a number between 1 and 9 to 5, or a two-digit number between 10 and 99 to 55. In the single-digit comparisons, DD children were…

Children sometimes solve problems incorrectly because they fail to represent key features of the problems. One potential source of improvements in children's problem representations is learning new problem-solving strategies. Ninety-one 3rd- and 4th-grade students solved mathematical equivalence problems (e.g., 3+4+6=3+__) and completed a…

The number line estimation task captures central aspects of children's developing number sense, that is, their intuitions for numbers and their interrelations. Previous research used children's answer patterns and verbal reports as evidence of how they solve this task. In the present study we investigated to what extent eye movements recorded…

We explore the immediate and longer term consequences of different types of instruction about a central topic in middle school science: the "Control of Variables Strategy" (CVS). CVS represents the procedural and conceptual basis for designing simple, unconfounded experiments, such that unambiguous causal inferences can be made. CVS…

Previous studies have suggested that children as young as 9 years old have developed an understanding of non-linear growth processes prior to formal education. The present experiment aimed at investigating this competency in even younger samples (i.e., in kindergartners, first, and third graders, ages 6, 7 and 9, respectively). Children (N=90)…

Deep orthographies usually represent morphology and phonology simultaneously; both resources are necessary for spelling. In shallow orthographies, such as Spanish, phonology would be enough to spell most words. However, morphological knowledge may also take part in spelling. This study examined how Spanish children in 1st (N = 148), 2nd (N = 155)…

Kindergarten, first-, and third-grade children were given a multitrial sort-recall task with different items on each trial. Children were asked to predict how many items they would recall prior to each trial. We classified children into high- and low-overestimation groups based on their prediction accuracy on the first two trials and assessed…

The present study explores how suppositions which conflict with accepted beliefs are represented and reasoned about. Two studies test the predictions regarding the nature and developmental changes in children's ability to represent and reason about hypothetical or make-believe suppositions which violate their everyday knowledge and beliefs. In…

An experiment investigated how methods of questioning affect children's responses regarding the shape of the earth and the day/night cycle. Seventy-two children from Grade 1 and Grade 3 in a middle-class elementary school in Athens, Greece, were tested either by an open method of questioning or by a forced-choice method of questioning. The two…