A foundational mechanism underlying human cooperation is reciprocity. In the context of repeated interactions with others, it is not always clear the degree to which in-kind responses reflect responsiveness to partners' prior behaviors ("reactive" responses), an interest unrelated to the partner ("nonreactive" responses), or…

As young as 3 years old, children rely on a mutual intentionality framework to confer group membership--that is, agreement between a joiner ("I want to be in your group") and group ("We want you to be in our group"). Here, we tested whether children apply this cognitive framework in the context of identity-based groups,…

It is widely accepted that investing in early childhood helps build the foundations of a healthy, productive, and equitable society. Guided by that knowledge, a range of broad-based programs and targeted services make a significant difference for millions of children, yet a closer look at outcome data shows that some benefit greatly, some benefit…

On a daily basis, children make decisions about how to negotiate their physical environment. Sometimes they engage in physical tasks that involve risk, requiring them to judge the safety of how to negotiate the environment safely. Individual differences in children's age, sex, physical size, and personality may impact those decisions. We used…

Students' experiences of physical education (PE) are considered important for lifelong attitudes towards physical activity. Sex-related differences and the individualised tempo in anthropometric growth because of biological maturation lead to secondary school students within chronological age-ordered classes possessing vast differences in…

Background: Adverse childhood experiences (ACEs) have long been associated with attention-deficit/hyperactive disorder (ADHD) diagnoses in children; but the data used is now over 6 years old (from 2017 to 2018). Understanding the current landscape of their prevalence and association is needed to capture evolving social, environmental, and economic…

Pretend play is one of the most beneficial and complex forms of play that promotes a myriad of children's development. Children's engagement in pretend play can be influenced by their genders, age, material or toys available, and adults' support. Pretend play has been long studied globally, however, there is still a dearth of available information…

Current understanding of how culture relates to the development of children's gender-related peer preferences is limited. To investigate the role of societal acceptance of gender nonconformity, this study compared children from China and Thailand. Unlike China and other cultures where the conceptualization of gender as binary is broadly accepted,…

Language development plays a pivotal role in a child's cognitive and overall growth, progressing through identifiable stages that ultimately lead to adult communication. It serves as a significant indicator of a child's intellectual and overall development. This study aims to explore the impact of daily technology use on children's language…

Effective communication is a fundamental aspect of children's daily living, enabling interaction with adults and peers. A rich literature suggests that communicative abilities develop with age, while little is known about cross-cultural differences and similarities. This study presents a comparison of the communicative performance of Finnish (n =…

The psychological mechanisms that subserve inductions about novel social categories in childhood are hotly debated. While research demonstrated that language, and in particular generic statements, plays a major role in how children learn to attribute properties to social categories, developmental theories propose other mechanisms. One theoretical…

Purpose: Limited quantitative data exist regarding growth of the velopharynx within the first 2 years of life. The purpose of this study was to (a) quantify changes in velopharyngeal structures due to growth during the first 2 years of life, (b) examine the impact of sex and race within this age range, and (c) provide normative measures for…

We leveraged nationally representative data from the Panel study of Income Dynamics-Child Development Supplement (N = 3,562) and the Early Childhood Longitudinal study (N = 18,174), to chart the development of working memory, indexed via verbal forward and backward digit span task performance, from 3 to 19 years of age. Results revealed nonlinear…

Developmental science has increasingly scrutinized how environmental hazards influence child outcomes, but few studies examine how contaminants affect disparities in early skill formation. Linking research on environmental inequality and early childhood development, this study assessed whether differences in exposure to neurotoxic lead explain…

The development of executive function (EF) has been linked to various life outcomes, motivating intense research on the topic. While much of this research has focused on more thoroughly understanding age-related changes of the underlying neurocognitive mechanisms involved, recent theoretical and empirical works have stressed how the immediate…