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  • 1.
    Lindström-Sandahl, Hanna
    et al.
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Elwér, Åsa
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Danielsson, Henrik
    Linköping University, Department of Behavioural Sciences and Learning, Disability Research Division. Linköping University, Faculty of Arts and Sciences. Linköping University, The Swedish Institute for Disability Research.
    Effects of a phonics intervention in a randomized controlled study in Swedish second-grade students at risk of reading difficulties2023In: Dyslexia, ISSN 1076-9242, E-ISSN 1099-0909, Vol. 29, no 4, p. 290-311Article in journal (Refereed)
    Abstract [en]

    Teaching phoneme awareness to children at risk for early reading difficulties has been recognized as successful in several studies. In this randomized controlled trial (RCT)-study, we add to this research by optimizing core procedural as well as teaching components in a phonics-directed intervention and extend the RCT reading intervention research into a semi-transparent language context. The aim of the present study was to evaluate the effects of a novel Swedish intensive phonics program. This randomized controlled pre-test and post-test intervention study targeted second-grade students with early reading difficulties. Students were identified by a repeated screening procedure and allocated to intervention (n = 34) and control (n = 34) conditions. A 9-week intensive phonics-based program was administrated one-to-one, by special education teachers in Swedish mainstream elementary schools. Results show an improvement in the intervention group, compared with the controls on all outcome measures. Findings indicate that the supplementary phonics program, delivered with high intensity, can significantly increase word reading skills and reading comprehension in second-grade students with early reading difficulties.

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  • 2.
    Treiman, Rebecca
    et al.
    Washington Univ St Louis, MO USA.
    Hulslander, Jacqueline
    Univ Colorado, CO USA.
    Olson, Richard K.
    Univ Colorado, CO USA.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Elwér, Åsa
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Furnes, Bjarte
    Univ Bergen, Norway.
    Byrne, Brian
    Univ New England, Australia.
    Predicting Later Spelling from Kindergarten Spelling in US, Australian, and Swedish Children2023In: Scientific Studies of Reading, ISSN 1088-8438, E-ISSN 1532-799X, Vol. 27, no 5, p. 428-442Article in journal (Refereed)
    Abstract [en]

    PurposeUsing data from 1,868 children from the US, Australia, and Sweden who took a 10-word spelling test in kindergarten and a standardized spelling test in Grades 1, 2, and (except for the Australian children) Grade 4, we examined two questions. First, does the quality of a childs errors on the kindergarten test help predict later spelling performance even after controlling for the number of correct responses on the kindergarten test? Second, does spelling develop at a faster pace in Swedish than in English?MethodWe measured kindergarten error quality based on the number of letter additions, deletions, and substitutions by which each error differed from the correct spelling. Using mixed-model analyses, we examined the relationship of this and other variables to later spelling performance.ResultsKindergarten error quality contributed significantly to the prediction of later spelling performance even after consideration of the number of correct spellings in kindergarten and other relevant variables. The Swedish children showed more rapid growth in spelling than the U.S. and Australian children, a difference that may reflect the greater transparency of sound-to-spelling links in Swedish.ConclusionInformation from a spelling test that is typically discarded - information about the nature of the errors -has value.

  • 3.
    Furnes, Bjarte
    et al.
    Univ Bergen, Norway.
    Elwér, Åsa
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Treiman, Rebecca
    Washington Univ, MO USA.
    Olson, Richard K.
    Univ Colorado, CO USA.
    The stability and developmental interplay of word reading and spelling: a cross-linguistic longitudinal study from kindergarten to grade 42023In: Reading and writing, ISSN 0922-4777, E-ISSN 1573-0905Article in journal (Refereed)
    Abstract [en]

    We investigated the stability and developmental interplay of word reading and spelling in samples of Swedish (N = 191) and U.S. children (N = 489) followed across four time points: end of kindergarten, grades 1, 2, and 4. Cross-lagged path models revealed that reading and spelling showed moderate to strong autoregressive effects, with reading being more predictable over time than spelling. Regarding the developmental interplay, we found a bidirectional relationship between reading and spelling from kindergarten to Grade 1. However, starting in Grade 1, reading predicted subsequent spelling beyond the autoregressor but not the other way around. In all analyses, the findings were similar across the two orthographies. The theoretical and practical implications of these findings are discussed.

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  • 4.
    Nilsson, Karin
    et al.
    Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, The Swedish Institute for Disability Research. Linköping University, Faculty of Arts and Sciences.
    Danielsson, Henrik
    Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences. Linköping University, The Swedish Institute for Disability Research.
    Elwér, Åsa
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Messer, David
    The Open University, UK; City, University of London, UK.
    Henry, Lucy
    City, University of London, UK.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Decoding Abilities in Adolescents with Intellectual Disabilities: The Contribution of Cognition, Language, and Home Literacy2021In: Journal of Cognition, E-ISSN 2514-4820, Vol. 4, no 1, p. 1-16Article in journal (Refereed)
    Abstract [en]

    Decoding abilities in individuals with intellectual disabilities (ID) are substantially lower than for typical readers. The underlying mechanisms of their poor reading remain uncertain. The aim of this study was to investigate the concurrent predictors of decoding ability in 136 adolescents with non-specific ID, and to evaluate the results in relation to previous findings on typical readers. The study included a broad range of cognitive and language measures as predictors of decoding ability. A LASSO regression analysis identified phonological awareness and rapid automatized naming (RAN) as the most important predictors. The predictors explained 57.73% of the variance in decoding abilities. These variables are similar to the ones found in earlier research on typically developing children, hence supporting our hypothesis of a delayed rather than a different reading profile. These results lend some support to the use of interventions and reading instructions, originally developed for typically developing children, for children and adolescents with non-specific ID.

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  • 5.
    Nilsson, Karin
    et al.
    Linköping University, The Swedish Institute for Disability Research. Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences.
    Danielsson, Henrik
    Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences. Linköping University, The Swedish Institute for Disability Research.
    Elwér, Åsa
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Messer, David
    The Open University, UK.
    Henry, Lucy
    City, University of London.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Investigating Reading Comprehension in Adolescents with Intellectual Disabilities: Evaluating the Simple View of Reading2021In: Journal of Cognition, E-ISSN 2514-4820, Vol. 4, no 1, p. 1-20Article in journal (Refereed)
    Abstract [en]

    Reading comprehension difficulties are common in individuals with intellectual disabilities (ID), but the influences of underlying abilities related to reading comprehension in this group have rarely been investigated. One aim of this study was to investigate the Simple View of Reading as a theoretical framework to describe cognitive and linguistic abilities predicting individual differences in reading comprehension in adolescents with non-specific ID. A second aim was to investigate whether predictors of listening comprehension and reading comprehension suggest that individuals with ID have a delayed pattern of development (copying early grade variance in reading comprehension) or a different pattern of development involving a new or an unusual pattern of cognitive and linguistic predictors. A sample of 136 adolescents with non-specific ID was assessed on reading comprehension, decoding, linguistic, and cognitive measures. The hypotheses were evaluated using structural equation models. The results showed that the Simple View of Reading was not applicable in explaining reading comprehension in this group, however, the concurrent predictors of comprehension (vocabulary and phonological executive-loaded working memory) followed a delayed profile.

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  • 6.
    Grasby, Katrina L.
    et al.
    QIMR Berghofer Med Res Inst, Australia.
    Little, Callie W.
    Univ New England, Australia; Univ Colorado, CO 80309 USA.
    Byrne, Brian
    Univ New England, Australia; Univ Colorado, CO 80309 USA.
    Coventry, William L.
    Univ New England, Australia; Univ Colorado, CO 80309 USA.
    Olson, Richard K.
    Univ Colorado Boulder, CO USA.
    Larsen, Sally
    Univ Colorado, CO 80309 USA.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Estimating Classroom-Level Influences on Literacy and Numeracy: A Twin Study2020In: Journal of Educational Psychology, ISSN 0022-0663, E-ISSN 1939-2176, Vol. 112, no 6, p. 1154-1166Article in journal (Refereed)
    Abstract [en]

    Classroom-level influences on literacy skills in kindergarten through Grade 2, and on literacy and numeracy skills in Grades 3. 5, 7, and 9. were examined by comparing the similarity of twins who shared or did not share classrooms with each other. We analyzed two samples using structural equation modeling adapted for twin data. The first, Study 1, was of Australia-wide tests of literacy and numeracy, with 1,098; 1,080; 790, and 812 complete twin pairs contributing data for Grades 3, 5, 7, and 9, respectively. The second, Study 2, was of literacy tests from 753 twin pairs from kindergarten through Grade 2, which included a sample of United States and Australian students and was a reanalysis and extension of Byrne et al. (2010). Classroom effects were mostly nonsignificant; they accounted for only 2-3% of variance in achievement when averaged over tests and grades. Although the averaged effects may represent a lower-bound figure for classroom effects, and the design cannot detect classroom influences limited to individual students, the results are at odds with claims in public discourse of substantial classroom-level influences, which are mostly portrayed as teacher effects.

  • 7.
    Byrne, Brian
    et al.
    University of New England, Australia.
    Olson, Richard K.
    University of Colorado, Boulder, USA.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Behavior-genetic studies of academic performance in school students: A commentary for professional in psychology and education2019In: Reading development and difficulties / [ed] David A. Kilpatrick, R. Malatesha Joshi, Richard K. Wagner, Cham: Springer, 2019, 1, p. 213-232Chapter in book (Refereed)
    Abstract [en]

    Available behavior-genetic research indicates that the single largest factor influencing individual differences in literacy development is genetic endowment. We briefly review some typical evidence and methodology used in studying the behavior-genetics of reading. We then outline three hypothetical educational scenarios and demonstrate how behavior-genetic studies might play out in them, with the aim of enhancing the critical capacity of school psychologists and other educational professionals to evaluate research findings in this area. We show that heritability estimates will tend to be higher in educational environments in which the instruction and other factors are more uniform, that the way subsamples are combined can affect estimates, and that population-level estimates cannot be used to determine the etiology of any individual child’s performance. We address and dismiss genetic determinism, and review evidence to suggest that genetic accounts of reading disability may reduce blame and stigma yet increase pessimism about successful intervention. However, we argue that continued research into optimal ways to design and deliver curricula is quite compatible with the substantial heritability of individual differences in literacy and has already provided grounds for optimism. We also suggest that genetically derived constraints on academic progress bring into sharp focus questions about the goals of education.

  • 8.
    MacDonald, Beatriz
    et al.
    Univ New Mexico, NM 87131 USA.
    Pennington, Bruce F.
    Univ Denver, CO 80208 USA.
    Willcutt, Erik G.
    Univ Colorado Boulder, CO USA.
    Dmitrieva, Julia
    Univ Denver, CO 80208 USA.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences. Univ Stavanger, Norway.
    Byrne, Brian
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences. Univ New England, Australia.
    Olson, Richard K.
    Linköping University. Univ Colorado Boulder, CO USA.
    Cross-Country Differences in Parental Reporting of Symptoms of ADHD2019In: Journal of Cross-Cultural Psychology, ISSN 0022-0221, E-ISSN 1552-5422, Vol. 50, no 6, p. 806-824Article in journal (Refereed)
    Abstract [en]

    Previous studies within the United States suggest there are cultural and contextual influences on how attention-deficit/hyperactivity disorder (ADHD) symptoms are perceived. If such influences operate within a single country, they are likely to also occur between countries. In the current study, we tested whether country differences in mean ADHD scores also reflect cultural and contextual differences, as opposed to actual etiological differences. The sample for the present study included 974 participants from four countries tested at two time points, the end of preschool and the end of second grade. Consistent with previous research, we found lower mean ADHD scores in Norway and Sweden in comparison with Australia and the United States, and we tested four explanations for these country differences: (a) genuine etiological differences, (b) slower introduction to formal academic skills in Norway and Sweden than in the United States and Australia that indicated a context difference, (c) underreporting tendency in Norway and Sweden, or (d) overreporting tendency in the United States and Australia. Either under- or overreporting would be examples of cultural differences in the perception of ADHD symptoms. Of these explanations, results of ADHD measurement equivalence tests across countries rejected the first three explanations and supported the fourth explanation: an overreporting tendency in the United States and Australia. These findings indicate that parental reporting of ADHD symptoms is more accurate in Norway and Sweden than in Australia and the United States, and, thus, have important clinical and educational implications for how parental reporting informs an ADHD diagnosis in these countries.

  • 9.
    McGowan, Dipti
    et al.
    Griffith Univ, Australia.
    Little, Callie W.
    Univ New England, Australia.
    Coventry, William L.
    Univ New England, Australia.
    Corley, Robin
    Univ Colorado, CO 80309 USA.
    Olson, Richard K.
    Univ Colorado, CO 80309 USA.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Byrne, Brian
    Univ New England, Australia.
    Differential Influences of Genes and Environment Across the Distribution of Reading Ability2019In: Behavior Genetics, ISSN 0001-8244, E-ISSN 1573-3297, Vol. 49, no 5, p. 425-431Article in journal (Refereed)
    Abstract [en]

    We partitioned early childhood reading into genetic and environmental sources of variance and examined the full distribution of ability levels from low through normal to high as computed by quantile regression. The full sample comprised twin pairs measured at preschool (n = 977), kindergarten (n = 1028), grade 1 (n = 999), and grade 2 (n = 1000). Quantile regression analyses of the full distribution of literacy ability showed genetic influence in all grades from preschool to grade 2. At preschool, the low end of the distribution had higher genetic influence than the high end of the distribution and the shared environment influence was the opposite. These shared environment influences of preschool became insignificant with formal schooling. This suggests that higher scores in pre-literacy skills (preschool) are more influenced by shared environment factors, though these are short-lived. This study discusses the factors that may be influencing the results.

  • 10.
    Olson, Richard
    et al.
    University of Colorado, Boulder, USA.
    Keenan, Janice
    University of Denver, USA.
    Byrne, Brian
    University of New England, Australia.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Etiology of developmental dyslexia2019In: Developmental dyslexia across languages and writing systems / [ed] Ludo Verhoeven, Charles Perfetti and Kenneth Pugh, New York: Cambridge University Press, 2019, 1, p. 391-412Chapter in book (Refereed)
  • 11.
    Furnes, Bjarte
    et al.
    Univ Bergen, Norway; Univ Stavanger, Norway.
    Elwér, Åsa
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Olson, Richard K.
    Univ Colorado, CO 80309 USA.
    Byrne, Brian
    Univ New England, Australia.
    Investigating the Double-Deficit Hypothesis in More and Less Transparent Orthographies: A Longitudinal Study from Preschool to Grade 22019In: Scientific Studies of Reading, ISSN 1088-8438, E-ISSN 1532-799X, Vol. 23, no 6, p. 478-493Article in journal (Refereed)
    Abstract [en]

    We investigated the double-deficit hypothesis (DDH) in samples of U.S. (N = 489), Australian (N = 264), and Scandinavian (N = 293) children followed from preschool to grade 2. Children were assigned to double deficit, single deficit and no deficit subtypes in preschool, kindergarten, and grade 1 and compared on reading and spelling in grades 1 and 2. In most analyses, the double deficit subtype scored significantly lower in reading and spelling than the single deficits, a pattern of findings that was identical across samples. Moreover, across countries, RAN deficits showed a stronger effect on reading whereas PA deficits showed stronger effects on spelling. Overall, the results supported the basic premises of the DDH suggesting that the double deficit subtype represents the most impaired readers, and that RAN and PA are separable deficits with different effects on reading and spelling. The results also supported a universal view of literacy development, with similar predictive patterns of DDH subtypes across orthographies.

  • 12.
    Leijon, Ingemar
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Children's and Women's health. Linköping University, Faculty of Medicine and Health Sciences.
    Ingemansson, Fredrik
    Linköping University, Department of Clinical and Experimental Medicine, Division of Children's and Women's health. Linköping University, Faculty of Medicine and Health Sciences.
    Nelson, Nina
    Linköping University, Department of Clinical and Experimental Medicine, Division of Children's and Women's health. Linköping University, Faculty of Medicine and Health Sciences.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Wadsby, Marie
    Linköping University, Department of Clinical and Experimental Medicine, Center for Social and Affective Neuroscience. Linköping University, Faculty of Medicine and Health Sciences.
    Children with a very low birthweight showed poorer reading skills at eight years of age but caught up in most areas by the age of 102018In: Acta Paediatrica, ISSN 0803-5253, E-ISSN 1651-2227, Vol. 107, no 11, p. 1937-1945Article in journal (Refereed)
    Abstract [en]

    AIM: We evaluated the development of reading skills in very low birthweight (VLBW) children and controls at 8-10 years of age.

    METHODS: This study was part of a longitudinal study of VLBW infants born between January 1998 and December 1999 in Sweden. We recruited 49 VLBW children and 44 sex and age-matched full-term controls when they started school at the age of seven and tested them using identical methods for decoding, rapid naming ability, reading comprehension, and spelling and cognitive skills at about eight and 10 years of age. Univariate analysis of variance was performed to assess the effects of VLBW on reading performance at each age and to evaluate the differences between the groups and ages.

    RESULTS: Very low birthweight children scored significantly lower in all domains of reading at 7.8 ± 0.3 years, but the performance gap had narrowed by 9.8 ± 0.3 years. Significant catch-up gains were found in phonological awareness, rapid naming ability and reading comprehension. The differences between the groups were minor at 10 years, when controlled for non-verbal cognition.

    CONCLUSION: Very low birthweight children demonstrated worse reading performance at eight years of age than term-born controls. The gap in reading skills between the groups had largely narrowed two years later.

  • 13.
    Peterson, Robin L
    et al.
    Children's hospital Colorado, USA.
    Arnett, Anne B
    University of Washington, Seattle, WA, USA.
    Pennington, Bruce F
    University of Denver, Colorado, USA.
    Byrne, Brian
    University of New England, Austarlia.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Olson, Richard K
    Uníversity of Colorado at Boulder, Colorado, USA.
    Literacy acquisition influences children's rapid automatized naming2018In: Developmental Science, ISSN 1363-755X, E-ISSN 1467-7687, Vol. 21, no 3, article id e12589Article in journal (Refereed)
    Abstract [en]

    Previous research has established that learning to read improves children's performance on reading‐related phonological tasks, including phoneme awareness (PA) and nonword repetition. Few studies have investigated whether literacy acquisition also promotes children's rapid automatized naming (RAN). We tested the hypothesis that literacy acquisition should influence RAN in an international, longitudinal population sample of twins. Cross‐lagged path models evaluated the relationships among literacy, PA, and RAN across four time points from pre‐kindergarten through grade 4. Consistent with previous research, literacy showed bidirectional relationships with reading‐related oral language skills. We found novel evidence for an effect of earlier literacy on later RAN, which was most evident in children at early phases of literacy development. In contrast, the influence of earlier RAN on later literacy was predominant among older children. These findings imply that the association between these two related skills is moderated by development. Implications for models of reading development and for dyslexia research are discussed.

  • 14.
    Olson, Rickard K
    et al.
    University of Colorado Boulder.
    Keenan, Janice M
    University of Denver.
    Byrne, Brian
    University of New England.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Genetic and environmental influences on the development of reading and related skills2017In: Theories of Reading Development / [ed] Cain, K., Compton, D. L., & Parrila, R. K, John Benjamins Publishing Company, 2017, p. 33-54Chapter in book (Refereed)
  • 15.
    Livingstone, Luisa T.
    et al.
    University of New England, Australia.
    Coventry, William L.
    University of New England, Australia.
    Corley, Robin P.
    University of Colorado, CO 80309 USA.
    Willcutt, Erik G.
    University of Colorado, CO 80309 USA.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences. Stavanger University, Norway.
    Olson, Richard K.
    University of Colorado, CO 80309 USA.
    Byrne, Brian
    University of New England, Australia.
    Does the Environment Have an Enduring Effect on ADHD? A Longitudinal Study of Monozygotic Twin Differences in Children2016In: Journal of Abnormal Child Psychology, ISSN 0091-0627, E-ISSN 1573-2835, Vol. 44, no 8, p. 1487-1501Article in journal (Refereed)
    Abstract [en]

    Environmental factors play a key role in the development of Attention-Deficit/Hyperactivity Disorder (ADHD), but the long-term effects of these factors are still unclear. This study analyses data from 1024 monozygotic (identical) twins in Australia, the United States, and Scandinavia who were assessed for ADHD in Preschool, Kindergarten, Grade 1, and Grade 2. Differences within each twin pair were used as a direct measure of non-shared environmental effects. The Trait-State-Occasion (TSO) model developed by Cole et al. (Psychological Methods, 10, 3-20, 2005) was used to separate the non-shared environmental effects into stable factors, and transient factors that excluded measurement error. Stable factors explained, on average, 44 % and 39 % of the environmental variance in hyperactive-impulsive and inattentive symptoms, respectively. Transient effects explained the remaining 56 % and 60 % of variance. The proportion of stable variance was higher than expected based on previous research, suggesting promise for targeted interventions if future research identifies these stable risk factors.

  • 16.
    Leijon, Ingemar
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center of Paediatrics and Gynaecology and Obstetrics, Department of Paediatrics in Linköping.
    Ingemansson, Fredrik
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences. Barn- och ungdomskliniken, Ryhovs sjukhus, Jönköping, Sverige.
    Nelson Follin, Nina
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center of Paediatrics and Gynaecology and Obstetrics, Department of Paediatrics in Linköping. Karolinska University Hospital, Sweden.
    Wadsby, Marie
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Reading deficits in very low birthweight children are associated withvocabulary and attention issues at the age of seven2016In: Acta Paediatrica, ISSN 0803-5253, E-ISSN 1651-2227, Vol. 105, no 1, p. 60-68Article in journal (Refereed)
    Abstract [en]

    AimThis Swedish study compared reading skills between seven-year-old children with a very low birthweight (VLBW) and controls with a normal birthweight, exploring associations between reading variables and cognition, parent-rated behaviour, perinatal factors and family factors. MethodsWe studied 51 VLBW children, with no major neurodevelopmental impairments and attending their first year at a regular school, and compared them with the 51 sex- and age-matched controls. The test battery, carried out at 7.80.4years of age, included reading skills, the Wechsler Intelligence Scale for Children - III and the Child Behaviour Checklist. ResultsVery low birthweight children with a mean birthweight of 1105g (+/- 291g) and a gestational age of 28.8 (+/- 2.2) weeks scored significantly lower in all reading subtests and cognition and demonstrated more behavioural problems than normal birthweight controls. We also found significant associations between poor vocabulary, combined with attention problems, and phonological awareness, rapid naming and spelling control. Perinatal factors had no association with reading function, and socio-economic factors had very few. ConclusionVery low birthweight children demonstrated deficits in all reading domains and had poorer cognition and more behavioural problems at the age of seven, with reading ability related to vocabulary and attention.

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  • 17.
    Elwér, Åsa
    et al.
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Gustafson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Byrne, Brian
    University of New England, Australia.
    Olson, Richard K.
    University of Colorado, CO 80309 USA.
    Keenan, Janice M.
    University of Denver, CO 80208 USA.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    A retrospective longitudinal study of cognitive and language skills in poor reading comprehension2015In: Scandinavian Journal of Psychology, ISSN 0036-5564, E-ISSN 1467-9450, Vol. 56, no 2, p. 157-166Article in journal (Refereed)
    Abstract [en]

    Fifty-six specific poor reading comprehenders (SPRC) were selected in Grade 4 and retrospectively compared to good comprehenders at preschool (age 5) and at the end of kindergarten, Grade 1, and Grade 2. The results revealed deficits in vocabulary, grammar, verbal memory and early deficits in phonological awareness in most of the SPRC sample, beginning in preschool. The reading comprehension deficits in children with SPRC were not as marked in earlier assessments in Grade 1 and 2, probably because of the greater dependence on word decoding in reading comprehension in the early grades.

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  • 18.
    Christopher, Micaela
    et al.
    University of Colorado Boulder, USA.
    Hulslander, Jacqueline
    University of Colorado Boulder, USA.
    Byrne, Brian
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences. University of New England, USA.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Keenan, Janice
    University of Denver, USA.
    Pennington, Bruce
    University of Denver, USA.
    DeFries, John
    University of Colorado Boulder, USA.
    Wadsworth, Sally
    University of Colorado Boulder, USA.
    Willcutt, Erik
    University of Colorado Boulder, USA.
    Olson, Richard
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Arts and Sciences. University of Colorado Boulder, USA.
    Genetic and environmental etiologies of the longitudinal relations between prereading skills and reading2015In: Child Development, ISSN 0009-3920, E-ISSN 1467-8624, Vol. 86, no 2, p. 342-361Article in journal (Refereed)
    Abstract [en]

    The present study explored the environmental and genetic etiologies of the longitudinal relations between prereading skills and reading and spelling. Twin pairs (n = 489) were assessed before kindergarten (M = 4.9 years), post-first grade (M = 7.4 years), and post-fourth grade (M = 10.4 years). Genetic influences on five prereading skills (print knowledge, rapid naming, phonological awareness, vocabulary, and verbal memory) were primarily responsible for relations with word reading and spelling. However, relations with post-fourth-grade reading comprehension were due to both genetic and shared environmental influences. Genetic and shared environmental influences that were common among the prereading variables covaried with reading and spelling, as did genetic influences unique to verbal memory (only post-fourth-grade comprehension), print knowledge, and rapid naming.

  • 19.
    Elwér, Åsa
    et al.
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Gustafson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Arts and Sciences.
    Byrne, Brian
    University of New England, Australia.
    Olson, Richard
    University of Colorado, Boulder, USA.
    Keenan, Janice
    University of Denver, CO, USA.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences. Stavanger University, Norway.
    A Retrospective Longitudinal Study of Cognitive and Language Skills in Poor Reading Comprehension2014Manuscript (preprint) (Other academic)
    Abstract [en]

    Fifty-six specific poor reading comprehenders (SPRC) were selected in grade 4 and retrospectively compared to good comprehenders at preschool age 5 and at the end of kindergarten, grade 1 and 2. The results showed a widespread language-deficit profile in children with SPRC, including deficits in vocabulary, grammar, verbal memory and early phonological awareness in a large part of the sample beginning in preschool. The reading comprehension deficits in children with SPRC were not as apparent in earlier assessments at grade 1 and 2, likely because of the greater dependence on word decoding in reading comprehension in the early grades.

  • 20.
    Wadsby, Marie
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Health Sciences.
    Nelson, Nina
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center of Paediatrics and Gynaecology and Obstetrics, Department of Paediatrics in Linköping.
    Ingemansson, Fredrik
    Ryhov County Hospital, Sweden.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Leijon, Ingemar
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center of Paediatrics and Gynaecology and Obstetrics, Department of Paediatrics in Linköping.
    Behaviour problems and cortisol levels in very-low-birth-weight children2014In: Nordic Journal of Psychiatry, ISSN 0803-9488, E-ISSN 1502-4725, Vol. 68, no 8, p. 626-632Article in journal (Refereed)
    Abstract [en]

    Background. There are still diverging results concerning the behaviour of children with very-low-birth-weight (VLBW) and they have been questioned to display different levels of stress hormone than normal-birth-weight (NBW) children. Aims. This study examined behaviour and the stress hormone cortisol in children with VLBW at the ages of 7 and 9 years compared with children with NBW. Results. Fifty-one VLBW and 50 NBW children were studied with the Child Behavior Checklist. Cortisol rhythm was measured through saliva samples three times a day for 2 days. VLBW children displayed more behavioural problems than NBW children, specifically social and attention problems, although still within normal ranges. They showed lower cortisol levels both at 7 and 9 years of age. No strong association between behaviour and cortisol levels was shown. Conclusion. VLBW children display more behaviour problems compared with NBW children but both groups score are within the normal range. Down-regulation of their hypothalamic-pituitary-adrenal (HPA) function in terms of lower cortisol levels is also noted.

  • 21.
    Byrne, Brian
    et al.
    University of New England, Australia.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Olson, Richard
    University of Colorado at Boulder, USA.
    Dyslexia2014In: The Routledge international companion to educational psychology / [ed] Andrew Holliman, London: Routledge, 2014, p. 297-306Chapter in book (Other academic)
  • 22.
    Elwér, Åsa
    et al.
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Furnes, Bjarte
    University of Bergen, Norway.
    Gustafson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Arts and Sciences.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences. Stavanger University, Norway.
    Pattern of Preschool Prediction of Reading Comprehension Impairment: A 10 Year Longitudinal Study2014Manuscript (preprint) (Other academic)
    Abstract [en]

    Compromised reading comprehension will invariably influence future academic achievements. In reading research there has been an emphasis on early identification of poor decoders to reduce future difficulties. Only a few studies have examined preschool prediction of reading comprehension impairments beyond the first grades of school, and these studies have presented different patterns of results. As studies have mostly been conducted in English; it is unclear how the results generalize to languages with transparent orthographies. In this study, a Swedish and a Norwegian twin sample were used to predict reading comprehension and decoding impairments in grade 2, 4 and 8/9 from preschool. The results suggested an important role for RAN and verbal memory. Compromised RAN was consistently associated with the poor decoders, as well as in identifying poor reading comprehenders in grade 8/9. Verbal memory tasks at preschool contributed to the identification of children with reading comprehension impairment across grades.

  • 23.
    Byrne, Brian
    et al.
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences. University of New England, Australia.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Olson, Richard
    University of Colorado, Boulder, USA.
    Reading and reading acquisition in European languages2014In: South and Southeast Asian psycholinguistics / [ed] Heather Winskel and Prakash Padakannaya, Cambridge: Cambridge University Press, 2014, p. 159-170Chapter in book (Other academic)
  • 24.
    Olson, Richard K
    et al.
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Educational Sciences. University of Colorado Boulder, USA.
    Keenan, Janice M
    University of Denver, CO, USA .
    Byrne, Brian
    University of New England, Australia.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Why Do Children Differ in Their Development of Reading and Related Skills?2014In: Scientific Studies of Reading, ISSN 1088-8438, E-ISSN 1532-799X, Vol. 18, no 1, p. 38-54Article in journal (Refereed)
    Abstract [en]

    Modern behavior-genetic studies of twins in the United States, Australia, Scandinavia, and the United Kingdom show that genes account for most of the variance in children's reading ability by the end of the 1st year of formal reading instruction. Strong genetic influence continues across the grades, though the relevant genes vary for reading words and comprehending text, and some of the genetic influence comes through a gene–environment correlation. Strong genetic influences do not diminish the importance of the environment for reading development in the population and for helping struggling readers, but they question setting the same minimal performance criterion for all children.

  • 25.
    Mårdh, Selina
    et al.
    The Swedish National Road and Transport Research Institute, Linköping, Sweden.
    Nägga, Katarina
    Clinical Memory Research, Lund University, Sweden.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    A longitudinal study of semantic memory impairment in patients with Alzheimer’s disease2013In: Cortex, ISSN 0010-9452, E-ISSN 1973-8102, Vol. 49, no 2, p. 528-533Article in journal (Refereed)
    Abstract [en]

    Introduction

    The present study explored the nature of the semantic deterioration normally displayed in the course of Alzheimer’s disease (AD). The aim was to disentangle the extent to which semantic memory problems in patients with AD are best characterized as loss of semantic knowledge rather than difficulties in accessing semantic knowledge.

    Method

    A longitudinal approach was applied. The same semantic tests as well as same items were used across three test occasions a year apart. Twelve Alzheimer patients and 20 matched control subjects, out of a total of 25 cases in each group, remained at the final test occasion.

    Results and Conclusions

    Alzheimer patients were impaired in all the semantic tasks as compared to the matched comparison group. A progressing deterioration was evident during the study period. Our findings suggest that semantic impairment is mainly due to loss of information rather than problems in accessing semantic information.

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  • 26.
    Elwér, Åsa
    et al.
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Keenan, Janice
    University of Denver, CO, USA.
    Olson, Richard
    University of Colorado, Boulder, USA.
    Byrne, Brian
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences. University of New England, Armidale, Australia.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences. Stavanger University, Norway.
    Longitudinal stability and predictors of poor oral comprehenders and poor decoders2013In: Journal of experimental child psychology (Print), ISSN 0022-0965, E-ISSN 1096-0457, Vol. 115, no 3, p. 497-516Article in journal (Refereed)
    Abstract [en]

    Two groups of fourth-grade children were selected from a population sample (= 926) to be either poor oral comprehenders (poor oral comprehension but normal word decoding) or poor decoders (poor decoding but normal oral comprehension). By examining both groups in the same study with varied cognitive and literacy predictors, and examining them both retrospectively and prospectively, we could assess how distinctive and stable the predictors of each deficit are. Predictors were assessed retrospectively at preschool and at the end of kindergarten, Grade 1, and Grade 2. Group effects were significant at all test occasions, including those for preschool vocabulary (worse in poor oral comprehenders) and rapid automatized naming (RAN) (worse in poor decoders). Preschool RAN and vocabulary prospectively predicted Grade 4 group membership (77–79% correct classification) within the selected samples. Reselection in preschool of “at-risk” poor decoder and poor oral comprehender subgroups based on these variables led to significant but relatively weak prediction of subtype membership at Grade 4. Implications of the predictive stability of our results for identification and intervention of these important subgroups are discussed.

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  • 27.
    Christopher, Micaela
    et al.
    University of Colorado Boulder, USA.
    Hulslander, Jacqueline
    University of Colorado Boulder, USA.
    Byrne, Brian
    University of New England, Australia.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Keenan, Janice
    University of Denver, USA.
    Pennington, Bruce
    University of Denver, USA.
    DeFries, John
    University of Colorado Boulder, USA.
    Wadsworth, Sally
    University of Colorado Boulder, USA.
    Willcutt, Erik
    University of Colorado Boulder, USA.
    Olson, Richard
    University of Colorado Boulder, USA.
    Modeling the etiology of individual differences in early reading development: Evidence for strong genetic influences2013In: Scientific Studies of Reading, ISSN 1088-8438, E-ISSN 1532-799X, Vol. 17, no 5, p. 350-368Article in journal (Refereed)
    Abstract [en]

    We explored the etiology of individual differences in reading development from post-kindergarten to post–4th grade by analyzing data from 487 twin pairs tested in Colorado. Data from three reading measures and one spelling measure were fit to biometric latent growth curve models, allowing us to extend previous behavioral genetic studies of the etiology of early reading development at specific time points. We found primarily genetic influences on individual differences at post–1st grade for all measures. Genetic influences on variance in growth rates were also found, with evidence of small, nonsignificant, shared environmental influences for two measures. We discuss our results, including their implications for educational policy.

  • 28.
    Byrne, Brian
    et al.
    University of New England, USA.
    Wadsworth, Sally
    University of Colorado, USA.
    Boehme, Kristi
    University of New England, USA.
    Coventry, William L
    University of New England, USA.
    Olson, Richard
    University of Colorado, USA.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Corley, Robin
    University of Colorado, USA.
    Multivariate genetic analysis of learning and early reading development2013In: Scientific Studies of Reading, ISSN 1088-8438, E-ISSN 1532-799X, Vol. 17, no 3, p. 224-242Article in journal (Refereed)
    Abstract [en]

    The genetic factor structure of a range of learning measures was explored in twin children, recruited in preschool and followed to Grade 2 (N = 2,084). Measures of orthographic learning and word reading were included in the analyses to determine how these patterned with the learning processes. An exploratory factor analysis of the genetic correlations among the variables indicated a three-factor model. Vocabulary tests loaded on the first factor, the Grade 2 measures of word reading and orthographic learning, plus preschool letter knowledge, loaded on the second, and the third was characterized by tests of verbal short-term memory. The three genetic factors correlated, with the second (print) factor showing the most specificity. We conclude that genetically influenced learning processes underlying print–speech integration, foreshadowed by preschool letter knowledge, have a degree of independence from genetic factors affecting spoken language. We also argue that the psychology and genetics of associative learning be afforded a more central place in studies of reading (dis)ability and suggest some links to molecular studies of the genetics of learning.

  • 29.
    Peterson, Robin
    et al.
    University of Denver, CO, USA.
    Pennington, Bruce
    University of Denver, CO, USA.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Byrne, Brian
    University of New England, Australia.
    Olson, Richard
    University of Colorado at Boulder, USA.
    Shared etiology of phonological memory and vocabulary deficits in school-age children2013In: Journal of Speech, Language and Hearing Research, ISSN 1092-4388, E-ISSN 1558-9102, Vol. 56, no 4, p. 1249-1259Article in journal (Refereed)
    Abstract [en]

    Purpose: The goal of this study was to investigate the etiologic basis for the association between deficits in phonological memory (PM) and vocabulary in school-age children.

    Method: Children with deficits in PM or vocabulary were identified within the International Longitudinal Twin Study (ILTS; Samuelsson et al., 2005). The ILTS includes 1,045 twin pairs (between the ages of 5 and 8 years) from the United States, Australia, and Scandinavia. The authors applied the DeFries-Fulker ( DeFries & Fulker, 1985, 1988) regression method to determine whether problems in PM and vocabulary tend to co-occur because of overlapping genes, overlapping environmental risk factors, or both.

    Results: Among children with isolated PM deficits, the authors found significant bivariate heritability of PM and vocabulary weaknesses both within and across time. However, when probands were selected for a vocabulary deficit, there was no evidence for bivariate heritability. In this case, it appears that the PM–vocabulary relationship is caused by common shared environmental experiences.

    Conclusions: The findings are consistent with previous research on the heritability of specific language impairment and suggest that there are etiologic subgroups of children with low vocabulary for different reasons, 1 being more influenced by genes and another being more influenced by environment.

  • 30.
    Christopher, Micaela
    et al.
    University of Colorado, Boulder, USA.
    Hulslander, Jacqueline
    University of Colorado, Boulder, USA.
    Byrne, Brian
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences. University of New England, Armidale, Australia.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Keenan, Janice
    University of Denver, USA.
    Pennington, Bruce
    University of Denver, USA.
    DeFries, John
    University of Colorado, Boulder, USA.
    Wadsworth, Sally
    University of Colorado, Boulder, USA.
    Willcutt, Eric
    University of Colorado, Boulder, USA.
    Olson, Richard
    University of Colorado, Boulder, USA.
    The genetic and environmental etiologies of individual differences in early reading growth in Australia, the United States and Scandinavia2013In: Journal of experimental child psychology (Print), ISSN 0022-0965, E-ISSN 1096-0457, Vol. 115, no 3, p. 453-467Article in journal (Refereed)
    Abstract [en]

    This first cross-country twin study of individual differences in reading growth from post-kindergarten to post-second grade analyzed data from 487 twin pairs from the United States, 267 twin pairs from Australia, and 280 twin pairs from Scandinavia. Data from two reading measures were fit to biometric latent growth models. Individual differences for the reading measures at post-kindergarten in the United States and Australia were due primarily to genetic influences and to both genetic and shared environmental influences in Scandinavia. In contrast, individual differences in growth generally had large genetic influences in all countries. These results suggest that genetic influences are largely responsible for individual differences in early reading development. In addition, the timing of the start of formal literacy instruction may affect the etiology of individual differences in early reading development but have only limited influence on the etiology of individual differences in growth.

  • 31.
    Arnett, Anett
    et al.
    University of Denver, CO, USA.
    Pennington, Bruce
    University of Denver, CO, USA.
    Friend, Angela
    University of Colorado, Boulder, USA.
    Willcutt, Eric
    University of Colorado, Boulder, USA.
    Byrne, Brian
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Arts and Sciences.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Olson, Richard
    University of Colorado, Boulder and Linköping university.
    The SWAN captures variance at the negative and positive ends of the ADHD Symptom dimension2013In: Journal of Attention Disorders, ISSN 1087-0547, E-ISSN 1557-1246, Vol. 17, no 2, p. 152-162Article in journal (Refereed)
    Abstract [en]

    Objective: The Strengths and Weaknesses of ADHD Symptoms and Normal Behavior (SWAN) Rating Scale differs from previous parent reports of ADHD in that it was designed to also measure variability at the positive end of the symptom spectrum. Method: The psychometric properties of the SWAN were tested and compared with an established measure of ADHD, the Disruptive Behavior Rating Scale (DBRS). Results: The SWAN demonstrates comparable validity, reliability, and heritability to the DBRS. Furthermore, plots of the SWAN and DBRS reveal heteroscedasticity, which supports the SWAN as a preferred measure of positive attention and impulse regulation behaviors. Conclusion: The ability of the SWAN to measure additional variance at the adaptive end of the ADHD symptom dimensions makes it a promising tool for behavioral genetic studies of ADHD.

  • 32.
    Arnett, Anne
    et al.
    University of Denver, USA.
    Pennington, Bruce
    University of Denver, USA.
    Willcutt, Erik
    University of Colorado, USA.
    Dmitrieva, Julia
    University of Denver, USA.
    Byrne, Brian
    University of New England, Armidale, Australia .
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Olson, Richard
    University of Colorado, USA.
    A cross-lagged model of the development of ADHD inattention symptoms and rapid naming speed2012In: Journal of Abnormal Child Psychology, ISSN 0091-0627, E-ISSN 1573-2835, Vol. 40, no 8, p. 1313-1326Article in journal (Refereed)
    Abstract [en]

    Although previous research has identified contemporaneous associations between cognitive deficits and symptom phenotypes in Attention Deficit/Hyperactivity Disorder, no studies have as yet attempted to identify direction of effect. The present study used cross-lagged path modeling to examine competing hypotheses about longitudinal associations between rapid naming speed and symptoms of inattention in children. 1,506 school-age twins from Australia and the U.S. were tested for inattention, hyperactivity/impulsivity, and rapid naming speed at three and four time points, respectively. Symptom severity of inattention from Kindergarten to fourth grade is consistently predicted by previous rapid naming, over and above auto-regressive and correlational associations in the model. Likewise, inattention symptoms have a small but significant predictive effect on subsequent rapid naming. The findings support a reciprocal relationship between naming speed and ADHD inattentive symptoms.

  • 33.
    Damber, Ulla
    et al.
    Mid Sweden University, Härnösand, Sweden.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Taube, Karin
    Umeå University, Sweden.
    Differences between overachieving and underachieving classes in reading: Teacher, classroom and student characteristics2012In: Journal of Early Childhood Literacy, ISSN 1468-7984, E-ISSN 1741-2919, Vol. 12, no 4, p. 339-366Article in journal (Refereed)
    Abstract [en]

    The main purpose of this study was to examine the classroom, teacher and student factors distinguishing grade three classes performing at higher levels than expected, in relation to socioeconomic status (SES) and language factors, from classes performing below their potential with regard to the same factors. Data from a standardized reading comprehension test and student and teacher questionnaires covering teacher, classroom and student characteristics were collected. The participants were 1,092 grade three classes and their class teachers, from Stockholm, Sweden. By use of regression and a twin-matching procedure, one group of 94 underachieving classes and another group of 94 overachieving classes were formed for comparison. Data about extended voluntary reading, classroom climate, teacher experience and the use of authentic literature were seen to the main four indicators discriminating between over- and underachieving classes beyond the impact of SES and language background.

  • 34.
    Pennington, Bruce
    et al.
    University of Denver.
    Santerre-Lemmon, Laura
    University of Denver.
    Rosenberg, Jennifer
    University of Denver.
    MacDonald, Beatriz
    University of Denver.
    Boada, Richard
    University of Denver.
    Friend, Angela
    University of Colorado.
    Byrne, Brian
    University of New England.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning.
    Willcutt, Eric
    University of Colorado.
    Olson, Richard
    University of Colorado.
    Individual prediction of dyslexia by single vs. multiple deficit models.2012In: Journal of Abnormal Psychology, ISSN 0021-843X, E-ISSN 1939-1846, Vol. 121, no 1, p. 212-224Article in journal (Refereed)
    Abstract [en]

    The overall goals of this study were to test single versus multiple cognitive deficit models of dyslexia (reading disability) at the level of individual cases and to determine the clinical utility of these models for prediction and diagnosis of dyslexia. To accomplish these goals, we tested five cognitive models of dyslexia-two single-deficit models, two multiple-deficit models, and one hybrid model-in two large population-based samples, one cross-sectional (Colorado Learning Disability Research Center) and one longitudinal (International longitudinal Twin Study). The cognitive deficits included in these cognitive models were in phonological awareness, language skill, and processing speed and/or naming speed. To determine whether an individual case fit one of these models, we used two methods: 1) the presence or absence of the predicted cognitive deficits, and 2) whether the individuals level of reading skill best fit the regression equation with the relevant cognitive predictors (i.e., whether their reading skill was proportional to those cognitive predictors.) We found that roughly equal proportions of cases met both tests of model fit for the multiple deficit models (30-36%) and single deficit models (24-28%); hence, the hybrid model provided the best overall fit to the data. The remaining roughly 40% of cases in each sample lacked the deficit or deficits that corresponded with their best-fitting regression model. We discuss the clinical implications of these results for both diagnosis of school-age children and preschool prediction of children at risk for dyslexia.

  • 35.
    Eriksson-Gustavsson, Anna-Lena
    et al.
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Läs- och skrivsatsningar i Linköpings kommun2012Report (Other academic)
  • 36.
    Byrne, Brian
    et al.
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Behavioural Sciences and Learning.
    Olson, Richard
    University of Colorado, USA.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    The longitudinal perspective on developmental disorders2012In: Current issues in developmental disorders / [ed] Chloë R. Marshall, Hove: Psychology Press, 2012, 1, p. 73-92Chapter in book (Other academic)
    Abstract [en]

    "Cognitive development in children is a highly complex process which, while remarkably resilient, can be disrupted in a variety of ways. This volume focuses on two types of neurodevelopmental disorder: syndromic conditions, such as fragile X syndrome, Down syndrome, Williams syndrome and Velocardiofacial syndrome; and non-syndromic conditions including dyslexia, specific language impairment, autism spectrum disorder and attention deficit hyperactivity disorder. This book provides a state-of-the-art review of current research and covers key topics across the full range of developmental disorders. Topics covered include: diagnosis and comorbidity genetics longitudinal studies computational models distinguishing disorder from deprivation/delay language and culture the history of research into developmental disorders The book also looks at how the study of developmental disorders has contributed to our understanding of typical development, and themes emerge that are common across chapters, including intervention and education, and the neurobiological bases of developmental disorders. The result is a fascinating and thought-provoking volume that will be indispensable to advanced students, researchers and practitioners in the fields of developmental psychology, neuropsychology, speech and language therapy and other developmental disorders"-- 

  • 37.
    Kempe, Camilla
    et al.
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Educational Sciences.
    Gustafson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning, Psychology. Linköping University, Faculty of Educational Sciences.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    A longitudinal study of early reading difficulties and subsequent problem behaviors2011In: Scandinavian Journal of Psychology, ISSN 0036-5564, E-ISSN 1467-9450, Vol. 52, no 3, p. 242-250Article in journal (Refereed)
    Abstract [en]

    It is generally believed that early academic failure in school develops into a downward spiral of negative motivational and behavioral consequences. In this study, children with reading difficulties were compared with typical readers on questionnaires measuring ADHD symptoms and other behavior problems such as withdrawn symptoms, somatic complaints, anxiety/depression, social problems, and aggression. The results revealed that reading difficulties and problem behaviors appear more independent of each other rather than problem behaviors being a consequence of reading failure. In addition, gender differenceswere negligible when examining the relationship between reading difficulties and subsequent problem behavior. Some implications for special educationand intervention are suggested.

  • 38.
    Kempe, Camilla
    et al.
    Linköping University, Department of Behavioural Sciences and Learning, Learning and Didactic Science in Education and School (PeDiUS). Linköping University, Faculty of Educational Sciences.
    Eriksson Gustavsson, Anna-Lena
    Linköping University, Department of Behavioural Sciences and Learning, Learning and Didactic Science in Education and School (PeDiUS). Linköping University, Faculty of Educational Sciences.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning, Learning and Didactic Science in Education and School (PeDiUS). Linköping University, Faculty of Educational Sciences.
    Are There Any Matthew Effects in Literacy and Cognitive Development?2011In: Scandinavian Journal of Educational Research, ISSN 0031-3831, E-ISSN 1470-1170, ISSN 0031-3831, Vol. 55, no 2, p. 181-196Article in journal (Refereed)
    Abstract [en]

    The Matthew effect is often used as a metaphor to describe a widening gap between good

    and poor readers over time. In this study we examined the development of individual

    differences in reading and cognitive functioning in children with reading difficulties and

    normal readers from Grades 1 to 3. Matthew effects were observed for individual

    differences in reading comprehension and vocabulary, but not on tests measuring word

    decoding, word recognition, or spelling, nor on non-verbal ability. However, these

    Matthew effects disappeared when controlling for home literacy activities and parent

    reading behavior, indicating that print exposure is one environmental condition involved

    in mediating Matthew effects. These findings are in line with the idea of the Matthew

    effect by Stanovich and the core assumption that reading comprehension is involved in

    a reciprocal relationship with vocabulary knowledge.

     

  • 39.
    Coventry, William L
    et al.
    University of New England.
    Byrne, Brian
    University of Colorado.
    Corley, Robin
    University of Colorado.
    Samuelsson, Stefan
    Linköping University, Faculty of Educational Sciences. Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning.
    Dynamic and Static Assessment of Phonological Awareness in Preschool: A Behavior-Genetic Study2011In: Journal of Learning Disabilities, ISSN 0022-2194, E-ISSN 1538-4780, Vol. 44, no 4, p. 322-329Article in journal (Refereed)
    Abstract [en]

    The genetic and environmental overlap between static and dynamic measures of preschool phonological awareness (PA) and their relation to preschool letter knowledge (LK) and kindergarten reading were examined using monozygotic and dizygotic twin children (maximum N = 1,988). The static tests were those typically used to assess a childs current level of PA such as blending and elision, and the dynamic test included instruction in phoneme identity to assess the childs ability to respond to this instruction. Both forms were influenced by genes and by shared and nonshared environment. The static and dynamic versions were influenced by the same genes, and part of the total genetic influence was shared with LK. They were subject to both overlapping and independent shared environment influences, with the component in common also affecting LK. Nonshared environment influences were mostly independent. Scores from dynamic assessment added only minimally to variance explained in kindergarten reading after LK and static assessment had been factored in. Although one of the genetic factors that influenced both forms of PA also affected kindergarten reading, it was only the one shared with LK. The authors conclude that dynamic assessment of PA in preschool offers little advantage over the more commonly used static forms, especially if LK scores are available, although they acknowledge its potential in cases of preschool educational disadvantage.

  • 40.
    Olson, Richard
    et al.
    Linköping University, Department of Behavioural Sciences and Learning, Learning and Didactic Science in Education and School (PeDiUS). Linköping University, Faculty of Educational Sciences.
    Keenan, Janice M
    University of Denver.
    Byrne, Brian
    Linköping University, Department of Behavioural Sciences and Learning, Learning and Didactic Science in Education and School (PeDiUS). Linköping University, Faculty of Educational Sciences.
    Samuelsson, Stefan
    Linköping University, Faculty of Educational Sciences. Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning.
    Coventry, William L
    University of New England.
    Corley, Robin
    University of Colorado.
    Wadsworth, Sally J
    University of Colorado.
    Willcutt, Erik G
    University of Colorado.
    DeFries, John C
    University of Colorado.
    Pennington, Bruce F
    University of Denver.
    Genetic and Environmental Influences on Vocabulary and Reading Development2011In: SCIENTIFIC STUDIES OF READING, ISSN 1088-8438, Vol. 15, no 1, p. 26-46Article in journal (Refereed)
    Abstract [en]

    Genetic and environmental relations between vocabulary and reading skills were explored longitudinally from preschool through Grades 2 and 4. At preschool there were strong shared-environment and weak genetic influences on both vocabulary and print knowledge but substantial differences in their source. Separation of etiology for vocabulary and reading continued for word recognition and decoding through Grade 4, but genetic and environmental correlations between vocabulary and reading comprehension approached unity by Grade 4, when vocabulary and word recognition accounted for all of the genetic and shared environment influences on reading comprehension.

  • 41.
    Furnes, Bjarte
    et al.
    Stavanger university.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Educational Sciences.
    Phonological awareness and rapid automatized naming predicting early development in reading and spelling: Results from a cross-linguistic longutudinal study.2011In: Learning and individual differences, ISSN 1041-6080, E-ISSN 1873-3425, Vol. 21, no 1, p. 85-96Article in journal (Refereed)
    Abstract [en]

    In this study, the relationship between latent constructs of phonological awareness (PA) and rapid automatized naming (RAN) was investigated and related to later measures of reading and spelling in children learning to read in different alphabetic writing systems (i.e., Norwegian/Swedish vs. English). 750 U.S./Australian children and 230 Scandinavian children were followed longitudinally between kindergarten and 2nd grade. PA and RAN were measured in kindergarten and Grade 1, while word recognition, phonological decoding, and spelling were measured in kindergarten, Grade 1, and Grade 2. In general, high stability was observed for the various reading and spelling measures, such that little additional variance was left open for PA and RAN. However, results demonstrated that RAN was more related to reading than spelling across orthographies, with the opposite pattern shown for PA. In addition, tests of measurement invariance show that the factor loadings of each observed indicator on the latent PA factor was the same across U.S./Australia and Scandinavia. Similar findings were obtained for RAN. In general, tests of structural invariance show that models of early literacy development are highly transferable across languages.

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  • 42.
    Brian, Byrne
    et al.
    University of New England.
    Khlentzos, Drew
    University of New England.
    Olson, Richard
    University of Colorado at Boulder.
    Samuelsson, Stefan
    Linköping University, Faculty of Educational Sciences. Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning.
    Evolutionary and genetic perspectives on educational attainment2010In: International handbook of psychology in education / [ed] Karen Littleton; Clare Wood; Judith Kleine Staarman, Bingley: Emerald Publishing Limited , 2010, 1, p. 3-33Chapter in book (Other academic)
    Abstract [en]

    "The International Handbook of Psychology in Education" provides researchers, practitioners and advisers working in the fields of psychology and education with an overview of cutting-edge research across a broad spectrum of work within the domain of psychology of education. The chapters in the handbook are authored by internationally recognised researchers, from across Europe, North America and the Pacific Rim. As well as covering the latest thinking within established areas of enquiry, the handbook includes chapters on recently emerging, yet important, topics within the field and explicitly considers the inter-relationship between theory and practice. A strong unifying theme is the volume's emphasis on processes of teaching and learning. The work discussed in the handbook focuses on typically developing school-age children, although issues relating to specific learning difficulties are also addressed.

  • 43.
    Ebejer, Jane L.
    et al.
    University of New England.
    Coventry, William L.
    University of New England.
    Byrne, Brian
    University of New England.
    Willcutt, Erik G.
    University of Colorado.
    Olson, Richard K.
    University of Colorado.
    Corley, Robin
    University of Colorado.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Educational Sciences.
    Genetic and Environmental Influences on Inattention, Hyperactivity-Impulsivity, and Reading: Kindergarten to Grade 22010In: Scientific Studies of Reading, ISSN 1088-8438, E-ISSN 1532-799X, Vol. 14, no 4, p. 293-316Article in journal (Refereed)
    Abstract [en]

    Twin children from Australia, Scandinavia, and the United States were assessed for inattention, hyperactivity-impulsivity, and reading across the first 3 school years. Univariate behavior-genetic analyses indicated substantial heritability for all three variables in all years. Longitudinal analyses showed one genetic source operating across the time span and a second entering in the second school year for each variable, though possibly not reliable for inattention. Other analyses confirmed previous findings of pleiotropy (shared genes) between inattention and reading and showed that this genetic overlap is in place from kindergarten onwards and is restricted to one of the genetic sources that affect reading and inattention. The results extend previous conclusions about the developmental trajectories of inattention, hyperactivity-impulsivity, and reading and their relationships. Limitations of this study are discussed, as are educational implications.

  • 44.
    Samuelsson, Stefan
    et al.
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Educational Sciences.
    Eriksson-Gustavsson, Anna-Lena
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Educational Sciences.
    Elwér, Åsa
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Educational Sciences.
    Kempe, Camilla
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Educational Sciences.
    Läs- och skrivforskning vid Linköpings universitet2010In: Dyslexi - aktuellt om läs- och skrivsvårigheter, Vol. 15, no 3, p. 29-31Article in journal (Other (popular science, discussion, etc.))
  • 45.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Educational Sciences.
    Några reflektioner kring läs- och skrivsvårigheter2010In: MANUS, ISSN 2000-4028, no 4, p. 10-11Article in journal (Other (popular science, discussion, etc.))
  • 46.
    Furnes, Bjarte
    et al.
    University of Bergen.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Educational Sciences.
    Predicting Reading and Spelling Difficulties in Transparent and Opaque Orthographies: A Comparison between Scandinavian and US/Australian Children2010In: DYSLEXIA, ISSN 1076-9242, Vol. 16, no 2, p. 119-142Article in journal (Refereed)
    Abstract [en]

    In this study, predictors of reading and spelling difficulties among children learning more transparent (Norwegian/Swedish) and less transparent (English) orthographies were examined longitudinally from preschool through Grade 2 using parallel versions of tests. A series of logistic regression analysis indicated three main findings. First, phonological awareness as a predictor of reading difficulties in the Scandinavian sample was time-limited to Grade 1, but remained as a significant predictor in the English-speaking sample. Second, phonological awareness predicted spelling difficulties similarly across orthographies. Third, preschool and kindergarten RAN was a significant predictor of reading and spelling difficulties at both Grades 1 and 2 across orthographies. The authors conclude that phonological awareness diminishes as a predictor of reading difficulties in transparent orthographies after the first years of schooling, that RAN is a better long-term predictor of reading difficulties, and that phonological awareness is associated with spelling difficulties similarly in transparent and opaque orthographies.

  • 47.
    Byrne, Brian
    et al.
    University of New England.
    Coventry, William L.
    University of New England.
    Olson, Richard K.
    University of Colorado.
    Wadsworth, Sally J.
    University of Colorado.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Educational Sciences.
    Petrill, Stephen A.
    Ohio State University.
    Willcutt, Erik G.
    University of Colorado.
    Corley, Robin
    University of Colorado.
    Teacher Effects in Early Literacy Development: Evidence From a Study of Twins2010In: Journal of Educational Psychology, ISSN 0022-0663, E-ISSN 1939-2176, Vol. 102, no 1, p. 32-42Article in journal (Refereed)
    Abstract [en]

    It is often assumed that differences in teacher characteristics area major source of variability in childrens educational achievements. We examine this assumption for early literacy achievement by calculating the correlations between pairs of twin children who either shared or did not share a teacher in kindergarten, Grade 1, and Grade 2. Teacher effects-or, more strictly, classroom effects-would show up as higher correlations for same-class than for different-class twin pairs. Same-class correlations were generally higher than different-class correlations.. though not significantly so on most occasions. On the basis of the results, we estimate that the maximum variance accounted for by being assigned to the same or different classrooms is 8%. This is an upper-bound figure for a teacher effect because factors other than teachers may contribute to variation attributable to classroom assignment. We discuss the limitations of the study and draw out some of its educational implications.

  • 48.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning, Learning and Didactic Science in Education and School (PeDiUS). Linköping University, Faculty of Educational Sciences.
    Beteendegenetisk läs- och skrivforskning2009In: Dyslexi och andra svårigheter med skriftspråket / [ed] Stefan Samuelsson m fl, Stockholm: Natur & Kultur , 2009, 1, p. 71-88Chapter in book (Other academic)
    Abstract [sv]

    Dyslexi och andra svårigheter med skriftspråketEtt stort antal elever lämnar skolan utan tillräcklig läs- och skrivförmåga. I denna bok får läsaren en god uppfattning om den världsomspännande och aktuella forskning som finns och ges även goda möjligheter att tillämpa den i sitt arbete.I boken 18 kapitel uppmärksammas pedagogisk, psykologisk och biologisk forskning om läs- och skrivsvårigheter. Författarna är lärare och forskare som ingår i ett nationellt nätverk för forskning om dyslexi och andra läs- och skrivsvårigheter.

  • 49.
    L Coventry, William
    et al.
    University of New England.
    Byrne, Brian
    University of Colorado.
    Corley, Robin
    University of Colorado.
    Willcutt, Eric
    University of Colorado.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Educational Sciences.
    Does Classroom Separation Affect Twins Reading Ability in the Early Years of School?2009In: TWIN RESEARCH AND HUMAN GENETICS, ISSN 1832-4274, Vol. 12, no 5, p. 455-461Article in journal (Refereed)
    Abstract [en]

    In this article we report on reading ability of twin children in kindergarten to Grade 2 as a function of whether members of the pairs are assigned to the same or different classrooms. All analyses were run using mixed model regressions to account for the interdependence between twin pairs. The samples, total N = 1505, are from Australia and the United States. We found a close-to-significant difference in favor of same-class children in kindergarten and Grade 1. However, when results were adjusted to take account of pre-existing differences in disruptive behavior and in preliteracy ability, the class assignment effects disappeared. We suggest that these pre-existing differences, particularly disruptive behavior, are influencing decisions about whether to separate twins or not and also affecting early reading performance, a conclusion supported by significant correlations between the behavioral measures, preliteracy, and school-based reading. We conclude that, on average, early literacy in twins is not directly affected by their assignment to the same or different classrooms.

  • 50.
    Coventry, William
    et al.
    Univ New England, Sch Behav Cognit and Social Sci, Armidale, NSW 2350, Australia.
    Byrne, Brian
    Univ New England, Sch Behav Cognit and Social Sci, Armidale, NSW 2350, Australia.
    Olson, Richard
    Univ Colorado, Dept Psychol, Boulder, CO 80309 USA.
    Samuelsson, Stefan
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Educational Sciences.
    Corley, Robin
    Univ Colorado, Dept Psychol, Boulder, CO 80309 USA.
    Does reading to your children moderate the genetic and environment etiology of their print knowledge and reading ability? in BEHAVIOR GENETICS, vol 39, issue 6, pp 642-6422009In: BEHAVIOR GENETICS, 2009, Vol. 39, no 6, p. 642-642Conference paper (Refereed)
    Abstract [en]

    n/a

123 1 - 50 of 139
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