Published papers

幼児、児童を対象とし、スマートフォンやタブレット等を用いて語彙力、視覚的ワーキングメモリ、推論能力を測定するためのオンライン認知検査を開発した。語彙力は「絵画ごい発達検査」を参考に、4種類のイラストを提示し、音声で提示される言葉に合致するイラストを１つ選択させ、その正答数を測定した。視覚的ワーキングメモリは欠落ドット検出課題(Di Lollo,1977)を参考に、マトリクス内に果物のイラストを配置した二つの画像を1000ミリ秒の刺激間間隔で継時提示し、画像を統合した時に空白となるセルを選択させその正答数を測定した。推論能力は「レーブン色彩マトリクス検査」を参考に、標準図案の欠如部分に合致するものを6つの選択図案の中から1つ選択させその正答数を測定した。全国から無作為抽出された年中児から小学2年生1300人以上から取得したデータについて、成績の分布、課題間の相関、年齢との相関などを検証する。

To examine the mechanisms underlying the relationship between academic achievement and grit, we divided grit into two dimensions: interest and perseverance. We explored these dimensions at the genetic and environmental levels using a behavioral genetic approach. The participants included 295 and 606 pairs of twins in elementary school and junior high school, respectively. At the phenotypic level, academic achievement positively correlated with perseverance across all school years. However, at the genetic and environmental levels, this relationship was shaped by environmental correlations among elementary school students and genetic correlations among junior high school students.

This study aimed to develop the Cognitive Abilities Test Online (CAT-O) for preschoolers and early school-age children. The scale's reliability, validity, and factor structure were also investigated. The CAT-O consists of three subtests: the Picture Vocabulary Test-Online, the Visual Reasoning Test-Online, and the Visual Working Memory Test-Online. Study 1 revealed that each of the three tests demonstrated good test-retest reliability. In terms of convergent validity, the three subtests demonstrated moderate to high significant positive correlations with similar scales. In Study 2, confirmatory factor analyses of ordered categorical data with a national random sample (N = 1,251) revealed that the three-factor model was the best fit. The high internal consistency of each test provided further evidence of its reliability. The mean levels of individual correct response rates and categorical factor scores progressed according to grade level, which also confirmed the validity of the CAT-O. Future research should focus on investigating the usability of the CAT-O in research and clinical settings.

During the COVID-19 pandemic, schools switched to online education. Using Japan’s nationwide administrative data, we examine the impact of schools’ ICT equipment and teachers’ IT skills on the provision of online classes, communication with students’ families, and teachers’ working hours in early 2020. To isolate supply-side effects, we exploit differences in ICT resources between public elementary and junior high schools at a municipality level, the level at which ICT resources are decided. We find that basic ICT equipment was critical to implementing online classes, but IT skills were not. However, IT skills were associated with teachers’ working hours.

We present new estimates of the internal rate of return to early childhood education. Utilizing the nationwide expansion of preschool education in Japan between 1960 and 1980, we initially assess the impact of preschool attendance on high school graduation and college enrollment for men. Subsequently, we compute the social rate of return to preschool attendance for men by drawing upon national wage statistics to project expected wage trajectories and referencing government documents to account for the social cost of preschools. Our findings indicate a social rate of return ranging from 5.7% to 8.1%, consistent with previous estimates in the literature.

Since the late 1990s, the number of college student loan debtors has increased rapidly in Japan. Despite the uniqueness of Japanese higher education policies in terms of tuition levels and heavy reliance on educational loans rather than grants, few studies have focused on the influence of student loans on adult youths’ lives. This study is the first to provide a detailed analysis of the relationship between student loan debt and youth life events. We explored the impact of student loan debt on family formation, using a data set of college graduates collected in 2017. We employed survival analysis methods to understand the relationship between student loan debt and marital decisions, and negative binomial models to analyze the impact of this debt on childbearing. The results showed that 2-year college graduate women with student loan debt were more likely to delay marital decisions than women without student loan debt. Taking out student loans also had a negative correlation to childbearing, which was also stronger for 2-year college graduate women. In conclusion, this study revealed that the Japanese government’s reliance on student loans has unexpected consequences. Even following recent reforms, student loan debt continues to be a major financial burden for young Japanese people and is likely to negatively affect family formation in Japan, which has already seen a decline in marriage and fertility rates over the last few decades. Our results call for additional policies to mitigate the negative influence of the Japanese college student aid system.

This paper provides new evidence on inequalities in resources for children age 3–4 by parental education using harmonized data from six advanced industrialized countries—United States, United Kingdom, France, Germany, Netherlands, and Japan—that represent different social welfare regime types. We analyze inequalities in two types of resources for young children—family income, and center-based child care—applying two alternative measures of parental education—highest parental education, and maternal education. We hypothesize that inequalities in resources by parental education will be less pronounced in countries where social policies are designed to be more equalizing. The results provide partial support for this hypothesis: the influence of parental education on resources for children does vary by the social policy context, although not in all cases. We also find that the measurement of parental education matters: income disparities are smaller under a maternal-only definition whereas child care disparities are larger. Moreover, the degree of divergence between the two sets of estimates differs across countries. We provide some of the first systematic evidence about how resources for young children vary depending on parents’ education and the extent to which such inequalities are buffered by social policies. We find that while early inequalities are a fact of life in all six countries, the extent of those inequalities varies considerably. Moreover, the results suggest that social policy plays a role in moderating the influence of parental education on resources for children.

This paper presents comparative information on the strength of the association between socioeconomic status (SES) and literacy skills at ages 6–8, drawing on data from France, Germany, Japan, Rotterdam (Netherlands), the United Kingdom, and the United States. We investigate whether the strength of the association between SES and literacy skills in early-to-mid childhood depends on the operationalization of SES (parental education, income, or both) and whether differences in inequalities at the end of lower secondary schooling documented in international large-scale assessments are already present when children have experienced at most two years of compulsory schooling. We find marked differences in SES-related inequalities in early achievement across countries that are largely insensitive to the way SES is measured and that seem to mirror inequalities reported for older students. We conclude that country context shapes the link between parental SES and educational achievement, with country differences rooted in the early childhood period.

This study examines the mechanisms through which grandparental resources and advantages increase the opportunities of grandchildren to access college, using longitudinal data from Japan. It also focuses on the heterogeneity in the transmission of grandparental advantages by lineage and gender. Although recent studies of social mobility have increasingly recognized the accumulation of inequality across multiple generations, relatively few studies have identified the underlying mechanisms or explored the roles of extended family structures in shaping multigenerational mobility. To advance this line of inquiry, we investigate how grandparental resources and contact are associated with grandchildren’s college enrollment in Japan—a context characterized by strong intergenerational ties and mutual support. We draw on two key mechanisms to explain multigenerational social mobility: the contact-based and noncontact-based mechanisms. In addition, we examine variation by grandparents’ lineage and gender. Our findings show that contact with paternal grandparents and grandfathers on both sides facilitates the transmission of their advantages to grandchildren, whereas no such pattern is observed for maternal grandmothers. These results underscore the importance of contact with grandfathers and patrilineal lineages in shaping multigenerational mobility in Japan. This contrasts with studies based on U.S. data, which emphasize the role of grandmothers. To deepen our understanding of multigenerational mobility, future research should shed light on how grandparental contact and resources operate across diverse family and societal settings.

This study investigated the role that daily communication between parents and teachers in childcare centers plays in enhancing parental self-efficacy, which in turn decreases the child's problem behaviors and improves the parent–child relationship. The data were drawn from 239 children (boys: N = 141; girls: N = 98; mean (SD) age = 4.95 (0.99) years) in formal childcare settings from the Japan Child Panel Survey-Preschool Survey. The results showed that daily communication between parents and teachers was positively related to parental self-efficacy, which was negatively related to child's problem behaviors and the conflictive parent–child relationship. Mediation analysis showed that parental self-efficacy mediated the association between parent–teacher communication and child's outcome and parent–child relationship. Furthermore, the association between parent–teacher communication and parental self-efficacy was moderated by socioeconomic status (SES), suggesting that higher-SES parents benefited more from daily parent–teacher communication compared with lower-SES parents. Child's daily experiences at childcare centers were not related to parental self-efficacy or any other outcomes. These findings suggest that daily communication between parents and teachers in childcare centers plays an indispensable role in supporting parents, which ultimately leads to positive child development and family well-being.

The COVID-19 pandemic resulted in school closures worldwide, including in Japan, where remote education at schools is underdeveloped. Using a unique panel dataset collected in May and December 2020, we examine the determinants of access to online education at and outside schools and parents’ preference towards at-school online education. We observe that children from more privileged family backgrounds received more at-school as well as outside-school online education. We also find that household income and parent's educational level are associated with higher demand for at-school online education, while mothers working full-time and fathers in non-regular contracts decreased this demand temporarily.