Purpose: This cross-sectional study aimed to investigate the ability to adjust grip strength by comparing the characteristics of force generation and relaxation from childhood to adulthood. Method: This study included 225 participants aged 6, 11, 17, and 19-23 years (adults) who performed isometric hand-grip force as follows: maximum, half…

We investigated performance levels on conducting continuous two-footed jumping of preschool children (4 years old) to high school students (16 years old) to clarify the developmental progression and sex differences in motor coordination and agility. In total, 450 children (boys: 227; girls: 223) participated in this study. We set 10 obstacles to…

Previous research on identity development among adolescents has focused on the processes involved. However, it is unclear how the sense of identity (synthesis and confusion) develops and how it relates to life satisfaction. This study aims to examine the relationship between sense of identity and life satisfaction among Japanese youth living in…

Differences in the frequency and differentiation of anger expression strategies, such as overt and constructive, and interpersonal contexts, such as parents and peers, were examined by sex and age in a community-based sample of 655 Japanese adolescents aged 9 to 16 years. The results revealed significant age-related differences in overt anger…

One of the challenges of developing assessments for young language learners is the shortage of evidence-based information about such assessments for languages other than English. In light of this situation, this paper discusses the development of an assessment for young languages learners in the context of Japanese as a second language (JSL). In…

Numeracy and literacy skills have become increasingly important in modern labour markets. The large gender differences that several studies have identified have therefore sparked considerable attention among researchers and policy makers. Little is known about the moment in which such gaps emerge, how they evolve and if their evolution differs…

Background: Physical activity is beneficial for adolescent health. The physical activity patterns of Japanese adolescents are relatively unknown. Therefore, this study aimed to describe the current patterns of physical activity and to identify sex and grade differences among them. Methods: The participants comprised 714 Japanese adolescents aged…

In this paper, we estimate the effect of pupil's relative age within the first grade of primary school on mathematics and reading test scores at age 15. The main objective is to evaluate the long-term causal effect of relative age in the first grades of primary school on pupil's test in 16 different countries. We use the national rule for…

Linguistic lateralization in 10 adolescents with Down syndrome (average age: 15.7 years), 15 adolescents with intellectual disabilities of unknown etiology (average age: 17.8 years), 2 groups of children without disabilities (11 children, average age: 4.7 years; 10 children, average age: 8.5 years), and 14 adolescents without disabilities (average…

Rating scale questionnaires were administered to 600 students in three age groups, 12-13, 15-16 and 20-21 from Japan, the UK, Greece and the USA. The questionnaires explored the extent of playing music while studying, the kinds of tasks when music was played, the perceived effects of music on studying, the characteristics and types of music played…

This study aimed to examine when children come to distinguish between the private affairs of an individual and the group's matter in relation to group decision making and whether there are any differences between Japan and England in learning the distinction. In total 217 children aged 8, 11, and 13 years, and undergraduates participated in the…

Surveyed fourth-, seventh-, and tenth-graders in Japan and the United States regarding evaluations of peer group exclusion of atypical peers. Found that with increasing age, children demonstrated sensitivity to context (reason the peer was different) and believed that the excluded child should not change to be accepted. Girls were less willing to…

Two studies investigated behavioral problems in childhood. Study 1 longitudinally investigated similarities and differences in enuresis and nailbiting among Japanese and American children. Incidences of enuresis decreased as subjects' age increased. Socio-cultural and family tolerance were related to incidences of nailbiting. In Study 2, changes…