Playing board games and other math activities can provide young children with opportunities to develop their math skills. However, it is critical to understand for whom these activities may be most beneficial. In two studies, we examine the extent to which foundational cognitive skills moderate the effects of playing math games on math skills. In…

Recent work suggests that common knowledge is an important cognitive mechanism for coordinating prosocial behavior, in part because it reduces uncertainty about others' cooperative behavior. However, it remains unclear whether children also rely on common knowledge to solve coordination problems. Here we examined whether 6- to 9-year-old children…

Children are sensitive to their own and others' epistemic states and use these to guide their learning and communication. Here, we systematically examined children's use of epistemic states to make diagnostic social inferences. Specifically, we investigated children's group membership inferences based on what others do and do not know and what…

Knowing the temporal direction of causal relations is critical for producing desired outcomes and explaining events. Existing evidence suggests that children start to grasp that causes must precede their effects (the temporal priority principle) by age 3; however, whether younger children also understand this has, to our knowledge, not previously…

The relation to operands (RO) principles describe the relation between operands and answers in arithmetic problems (e.g., the sum is always larger than its positive addends). Despite being a fundamental property of arithmetic, its empirical relation with arithmetic/algebraic problem solving has seldom been investigated. The current longitudinal…

Young children have informal knowledge of fractions before learning about fraction symbols in school. In the current study, we followed 103 children in the Mid-Atlantic United States from the fall to the spring of first grade to characterize the development of individual differences in early informal fraction knowledge, as well as its relation to…

Debates about lowering the voting age often center on whether 16- and 17-year-old adolescents possess sufficient cognitive capacity and political knowledge to participate in politics. Little empirical research has examined age differences in adolescents' and adults' complexity of reasoning about political issues. We surveyed adults (n = 778;…

We investigated 4- and 5-year-olds' (N = 194) appreciation of the link between knowledge and ownership. Namely, we asked whether preschoolers appreciate the ways in which owners are typically knowledgeable about artifacts. Experiment 1 revealed that 4- and 5-year-olds view owners as better sources of knowledge about artifacts than those who simply…

"Place value," which underlies the meanings of multidigits, encompasses the principle of position and base-10 rules. To understand 65, one needs to know that the digits 6 and 5 occupy different positions and thus represent ordered values of different magnitudes (i.e., the "principle of position") and that the value of each…

Many middle-school students struggle with basic reading skills. One reason for this might be a lack of automaticity in word-level lexical processes. To investigate this, we used a novel backward masking paradigm, in which a written word is either covered with a mask or not. Participants (N = 444 [after exclusions]; n[subscript female] = 264,…

The present study tests two predictions stemming from the hypothesis that a source of difficulty with rational numbers is interference from whole number magnitude knowledge. First, inhibitory control should be an independent predictor of fraction understanding, even after controlling for working memory. Second, if the source of interference is…

We examined the development of numerical magnitude representations of fractions and decimals from fourth to 12th grade. In Experiment 1, we assessed the rational number magnitude knowledge of 200 Chinese fourth, fifth, sixth, eighth, and 12th graders (92 girls and 108 boys) by presenting fraction and decimal magnitude comparison tasks as well as…

The current study investigated whether children understand the conditions under which another agent would hold uncertain knowledge resulting from inferential processes and, more importantly, whether children can make causal inferences about the relationship between the certainty of an agent's epistemic states and consequent behavioral strategies.…

Many factors at the individual, relationship, family, and community or environmental levels could predict repeat teen pregnancies or births, but research on certain factors is limited. In addition, few studies have examined whether these factors can accurately predict whether teen mothers will have a repeat pregnancy. This study examined…

Testimony is a valuable source of information for young learners, in particular if children maintain vigilance against errors while still being open to learning from imperfectly knowledgeable sources. We find support for this idea by examining how children evaluate individual speakers who present very different epistemic risks by being previously…