Fujisawa, Keiko



Faculty of Letters, Department of Humanities and Social Science (Human Relations) (Mita)



Career 【 Display / hide

  • 2007.04

    慶應義塾大学, 文学部, 助教

  • 2015.04

    慶應義塾大学, 文学部, 准教授

Academic Degrees 【 Display / hide

  • 博士(学術), The University of Tokyo, 2007


Research Areas 【 Display / hide

  • Humanities & Social Sciences / Educational psychology


Papers 【 Display / hide

  • Changes in genetic and environmental influences on cognitive ability, executive function, and preacademic skills in japanese preschool age twins

    Fujisawa K., Todo N., Ando J.

    Developmental Psychology (Developmental Psychology)  55 ( 1 ) 38 - 52 2019.01

    Research paper (scientific journal), Joint Work, Accepted,  ISSN  00121649

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    © 2018 American Psychological Association. Identifying the cognitive capacities associated with the development of school readiness is indispensable to support children's successful school transition. It has been shown that executive function (EF) in preschoolers is associated with both concurrent preacademic and subsequent academic skills. However, most research has controlled for the effect of general cognitive ability (GCA), and little research has examined non-English speaking children, which hinders the understanding of the development of school readiness in culturally diverse contexts. In addition, behavioral genetic research on the genetic and environmental influences on this association has been conducted with school-age children. Thus, the genetic and environmental influences on associations between GCA, EF, and preacademic skills during preschool age are unknown. We conducted multivariate behavioral genetic analyses on two waves of longitudinal data at 42 and 60 months of age from 171 and 135 pairs of monozygotic and dizygotic Japanese twins. The findings suggested that a genetic factor influenced GCA at 42 months and mediated preacademic ability at 60 months. In addition, another genetic factor emerged by 60 months that genetically mediated EF and math ability, independent of GCA. Preacademic ability at 60 months was affected by shared environments that influenced EF, rather than GCA, at 42 months. Moreover, shared environments that influenced preacademic ability at 42 months affected later GCA at 60 months. Finally, nonshared environments that had emerged by 60 months mediated these relationships, though the magnitude of this effect was modest.

  • Genetic and environmental influences on the development and stability of executive functions in children of preschool age: A longitudinal study of Japanese twins

    Fujisawa K. K., Todo N., Ando J.

    Infant and Child Development (Infant and Child Development)  26 ( 3 )  2016

    Research paper (scientific journal), Joint Work, Accepted,  ISSN  15227227

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    Copyright © 2016 John Wiley & Sons, Ltd. Executive functions (EF) are an important predictor of later adaptive development. A number of environmental influences, such as parenting, have been suggested as important promoters of EF development. However, behavioural genetic research has demonstrated that many environmental influences could be affected by genetic influences. Therefore, it is important to consider genetic variations when investigating environmental influences on EF development in children. To date, few studies have used genetically informative designs to assess the etiology of EF development during the preschool years, a period of rapid development. As a result, it remains unclear how and to what extent the environmental influences that are not confounded by genetic influences affect EF development during this developmental period. The present study explored EF development during the preschool years using a longitudinal and genetically informative design and a non-Western population. Japanese twins were visited at their homes and individually tested on EF measures at 24, 36, and 48 months of age. Phenotypic correlations and confirmatory factor analyses suggested that EF are less cohesive at 24 months of age and emerge as a common single factor at 36 and 48 months. Additionally, longitudinal and multivariate behavioural genetic analyses indicated that the EF developmental change during this period is promoted by both shared and nonshared environmental influences as well as genetic influences, while EF stability is brought about by shared environments. The present findings elucidated the etiology of EF development during the preschool years and confirmed that this period is an important transitional stage for EF development. Copyright © 2016 John Wiley & Sons, Ltd.

  • Two Cohort and Three Independent Anonymous Twin Projects at the Keio Twin Research Center (KoTReC).

    Ando, J., Fujisawa, K., K., Shikishima, C., Hiraishi, K., Nozaki, M., Yamagata, S., … Ooki, S.

    Twin Research and Human Genetics (Twin Research and Human Genetics)  16 ( 1 ) 202 - 216 2013

    Research paper (scientific journal), Joint Work, Accepted,  ISSN  18324274

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    The Keio Twin Research Center has conducted two longitudinal twin cohort projects and has collected three independent and anonymous twin data sets for studies of phenotypes related to psychological, socio-economic, and mental health factors. The Keio Twin Study has examined adolescent and adult cohorts, with a total of over 2,400 pairs of twins and their parents. DNA samples are available for approximately 600 of these twin pairs. The Tokyo Twin Cohort Project has followed a total of 1,600 twin pairs from infancy to early childhood. The large-scale cross-sectional twin study (CROSS) has collected data from over 4,000 twin pairs, from 3 to 26 years of age, and from two high school twin cohorts containing a total of 1,000 pairs of twins. These data sets of anonymous twin studies have mainly targeted academic performance, attitude, and social environment. The present article introduces the research designs and major findings of our center, such as genetic structures of cognitive abilities, personality traits, and academic performances, developmental effects of genes and environment on attitude, socio-cognitive ability and parenting, genes x environment interaction on attitude and conduct problem, and statistical methodological challenges and so on. We discuss the challenges in conducting twin research in Japan. Copyright © The Authors 2013.

  • Bidirectional influences between maternal parenting and children’s peer problems: A longitudinal monozygotic twin difference study.

    Yamagata, S., Takahashi, Y., Ozaki, K., Fujisawa, K. K., Nonaka, K., Ando, J.

    Developmental Science (Developmental Science)  16 ( 2 ) 249 - 259 2013

    Research paper (scientific journal), Joint Work, Accepted,  ISSN  1363755X

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    This twin study examined the bidirectional relationship between maternal parenting behaviors and children's peer problems that were not confounded by genetic and family environmental factors. Mothers of 259 monozygotic twin pairs reported parenting behaviors and peer problems when twins were 42 and 48 months. Path analyses on monozygotic twin difference scores revealed that authoritative parenting (the presence of consistent discipline and lack of harsh parenting) and peer problems simultaneously influenced each other. Authoritative parenting reduced peer problems, and peer problems increased authoritative parenting. Neither consistent discipline nor harsh parenting alone was associated with peer problems. These results suggest that maternal authoritative parenting works protectively in regard to children's peer problems, and peer problems can evoke such effective parenting. © 2012 Blackwell Publishing Ltd.

  • A multivariate twin study of early literacy in Japanese kana.

    Fujisawa, K. K., Wadsworth, S. J., Kakihana, S., Olson, R.K., DeFries, J. C., Byrne, B., Ando, J.

    Learning and Individual Differences (Learning and Individual Differences)  24   160 - 167 2013

    Research paper (scientific journal), Joint Work, Accepted,  ISSN  10416080

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    This first Japanese twin study of early literacy development investigated the extent to which genetic and environmental factors influence individual differences in prereading skills in 238 pairs of twins at 42. months of age. Twin pairs were individually tested on measures of phonological awareness, kana letter name/sound knowledge, receptive vocabulary, visual perception, nonword repetition, and digit span. Results obtained from univariate behavioral-genetic analyses yielded little evidence for genetic influences, but substantial shared-environmental influences, for all measures. Phenotypic confirmatory factor analysis suggested three correlated factors: phonological awareness, letter name/sound knowledge, and general prereading skills. Multivariate behavioral genetic analyses confirmed relatively small genetic and substantial shared environmental influences on the factors. The correlations among the three factors were mostly attributable to shared environment. Thus, shared environmental influences play an important role in the early reading development of Japanese children. © 2012 Elsevier Inc.

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Papers, etc., Registered in KOARA 【 Display / hide

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Research Projects of Competitive Funds, etc. 【 Display / hide

  • 幼児教育・保育の質の向上につながる評価プロセス


    基盤研究(B), Principal investigator

  • 良好な就学への移行をもたらす保育の質の解明


    MEXT,JSPS, Grant-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Principal investigator

  • 経済格差と教育格差の長期的因果関係の解明:親子の追跡データによる分析と国際比較


    文部科学省・日本学術振興会, 基盤研究(S), Coinvestigator(s)

  • 貧困と災害の教育経済学:社会的不利や困難に打ち勝つ子供をどう育てるか


    文部科学省・日本学術振興会, 基盤研究(A), Coinvestigator(s)

  • 養育態度が実行機能の発達に及ぼす影響に関する発達行動遺伝学研究


    文部科学省・日本学術振興会, 若手研究(A), Principal investigator

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