Very large numbers words such as "hundred," "thousand," "million," "billion," and "trillion" pose a learning problem for children because they are sparse in everyday speech and children's experience with extremely large quantities is scarce. In this study, we examine when children acquire the…

Empirical studies on selective teaching and informing indicate that children may vary what they teach depending on whom they are teaching, taking into account how helpful the information is for a given audience. The current meta-analysis quantifies the effect of selective informing and teaching in 2-7-year-olds by examining the relationship…

There is extensive research on the development of cheating in early childhood but research on how to reduce it is rare. The present preregistered study examined whether telling young children about a story character's emotional reactions towards cheating could significantly reduce their tendency to cheat (N = 400; 199 boys; Age: 3-6 years).…

Numerous studies have documented children's understanding of fairness through their ability to rectify inequities when distributing resources to others. Understanding fairness, however, involves more than just applying norms of equity when distributing resources. Children must also navigate situations in which resources are collected from them for…

Previous findings on the association between theory of mind (ToM) and aggression in children are mixed. The "social skills deficit view" regarded ToM as a "single-edged sword" and proposed that a lack of ToM can lead to aggression, while the "double-edged sword view" proposed that children with advanced ToM can still…

Researchers commonly use puppets in development science. Amongst other things, puppets are employed to reduce social hierarchies between child participants and adult experimenters akin to peer interactions. However, it remains controversial whether children treat puppets like real-world social partners in these settings. This study investigated…

Identifying abstract relations is essential for commonsense reasoning. Research suggests that even young children can infer relations such as "same" and "different," but often fail to apply these concepts. Might the process of explaining facilitate the recognition and application of relational concepts? Based on prior work…

Children learn language by listening to speech from caregivers around them. However, the type and quantity of speech input that children are exposed to change throughout early childhood in ways that are poorly understood due to the small samples (few participants, limited hours of observation) typically available in developmental psychology. Here…

Preverbal infants spontaneously represent the number of objects in collections. Is this 'sense of number' (also referred to as Approximate Number System, ANS) part of the cognitive foundations of mathematical skills? Multiple studies reported a correlation between the ANS and mathematical achievement in children. However, some have suggested that…

Even once children can accurately remember their experiences, they nevertheless struggle to use those memories in flexible new ways--as in when drawing inferences. However, it remains an open question as to whether the developmental differences observed during both memory formation and inference itself represent a fundamental limitation on…

Which dimension of a set of objects is more salient to young children: number or size? The "Build-A-Train" task was developed and used to examine whether children spontaneously use a number or physical size approach on an un-cued matching task. In the Build-A-Train task, an experimenter assembles a train using one to five blocks of a…

What drives children to explore and learn when external rewards are uncertain or absent? Across three studies, we tested whether information gain itself acts as an internal reward and suffices to motivate children's actions. We measured 24-56-month-olds' persistence in a game where they had to search for an object (animal or toy), which they never…

Bilingual environments present an important context for word learning. One feature of bilingual environments is the existence of translation equivalents (TEs)--words in different languages that share similar meanings. Documenting TE learning over development may give us insight into the mechanisms underlying word learning in young bilingual…

Although actual experiences of upward social mobility are historically low, many adolescents and adults express a "belief" in social mobility (e.g., that social status can change). Although a belief in upward mobility (e.g., that status can improve) can be helpful for economically disadvantaged adolescents and adults, a belief in upward…

Children's sharing behavior is profoundly shaped by social norms within their society, and they can learn these norms by directly observing how most others share in their immediate environment. Here we systematically investigated the impact of majority influence on the sharing behavior of young Chinese children through three studies (N = 336, 168…