Health and Disability Home environmental influences on children’s language and reading skills in a genetically sensitive design: Are socioeconomic status and home literacy environment environmental mediators and moderators? BONNIE WING-YIN CHOW, 1 CONNIE SUK-HAN HO, 2 SIMPSON W. L. WONG, 3 MARY. M. Y. WAYE 4 and MO ZHENG 2 1 City University of Hong Kong, Hong Kong, China 2 The University of Hong Kong, Hong Kong, China 3 Hong Kong Baptist University, Hong Kong, China 4 The Nethersole School of Nursing, The Chinese University of Hong Kong, Hong Kong, China Chow, B. W.-Y., Ho, C. S.-H., Wong, S. W. L., Waye, M. M. Y. & Zheng, M. (2017). Home environmental influences on children’s language and reading skills in a genetically sensitive design: Are socioeconomic status and home literacy environment environmental mediators and moderators?. Scandinavian Journal of Psychology. This twin study examined how family socioeconomic status (SES) and home literacy environment (HLE) contributes to Chinese language and reading skills. It included 312 Chinese twin pairs aged 3 to 11. Children were individually administered tasks of Chinese word reading, receptive vocabulary and reading-related cognitive skills, and nonverbal reasoning ability. Information on home environment was collected through parent-reported questionnaires. Results showed that SES and HLE mediated shared environmental influences but did not moderate genetic influences on general language and reading abilities. Also, SES and HLE mediated shared environmental contributions to receptive vocabulary and syllable and rhyme awareness, but not orthographic skills. The findings of this study add to past twin studies that focused on alphabetic languages, suggesting that these links could be universal across languages. They also extend existing findings on SES and HLE’s contributions to reading-related cognitive skills. Key words: Language and reading skills, reading-related cognitive skills, family socioeconomic status, home literacy environment, twin study. Bonnie Wing-Yin Chow, Department of Applied Social Sciences, City University of Hong Kong, Hong Kong, China. Tel: 852-34428954; e-mail: wychow@cityu.edu.hk INTRODUCTION Home environment is an important predictor of children’s language and reading development (Griffin & Morrison, 1997). Ample research evidence has demonstrated the links between children’s language and reading skills and various home environmental factors, particularly family socioeconomic status (SES; e.g., Fernald, Marchman & Weisleder, 2013; Hecht, Burgess, Torgesen, Wagner & Rashotte, 2000) and home literacy environment (HLE; e.g., Aram, Korat & Hassunah-Arafat, 2013; Payne, Whitehurst & Angell, 1994). A few twin studies have further examined the mechanisms of these links, and have shown that home environment, including SES, home chaos, and parental education, mediated environmental influences and moderated genetic effects on language and reading skills (e.g., Friend, DeFries & Olson, 2008; Petrill, Pike, Price & Plomin, 2004). However, studies of this kind remain scarce and mixed results have been demonstrated, and solid conclusions have not yet been made. This study aims to provide a more complete picture of the roles of SES and HLE in language development by examining whether they mediate environmental influences and/or moderate genetic effects on Chinese language and reading skills in a single study with 312 Chinese twin pairs aged 3 to 11 years. Socioeconomic status and home literacy environment The correlations between family SES and HLE and children’s language and literacy development have been well documented in psychological and educational research (e.g., Aikens & Barbarin, 2008). Family SES reflects the resources and assets that the household possesses, which is not limited to material resources but also includes nonmaterial ones, such as education opportunities and social networks (Bradley & Corwyn, 2002). Despite its relatively broad nature in conceptualization, family SES has been widely tapped by household income, and parental education level and occupational status in developmental psychology studies (Bradley & Corwyn, 2002). Children from a high SES family often perform better on reading and related cognitive skills, including phonological awareness, and significant and persisting effects of SES on reading skills across time have been shown in longitudinal studies (e.g., Bowey, 1995; Raz & Bryant, 1990; Molfese, Modglin & Molfese, 2003). For instance, Hecht et al. (2000) provide evidence of SES differences in word decoding in each year from kindergarten to grade four when prior word decoding skills were controlled. Also, they found family SES in kindergarten explained 7% of variances in fourth-grade word decoding skills after prior decoding skills, general verbal intelligence, phonological awareness, rate of access, and print knowledge were accounted for. These influences of family SES have not been confined to Western cultures. Research has found family SES represented by maternal education was significantly linked to children’s vocabulary knowledge and family SES represented by parental income, education and occupation was correlated with children’s word reading in the Chinese culture (e.g., Lau & McBride-Chang, 2005; Liu, Chung & McBride, 2016). © 2017 Scandinavian Psychological Associations and John Wiley & Sons Ltd Scandinavian Journal of Psychology, 2017 DOI: 10.1111/sjop.12397