UNE CRIS V7 :: Browsing by Author "Olson, Richard K"

Browsing by Author "Olson, Richard K"

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The Academic Development Study of Australian Twins (ADSAT): Research Aims and Design
(Cambridge University Press, 2020-06-02)
Larsen, Sally A
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Little, Callie W
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Grasby, Katrina
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Byrne, Brian
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Olson, Richard K
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Coventry, William L
The Academic Development Study of Australian Twins was established in 2012 with the purpose of investigating the relative influence of genes and environments in literacy and numeracy capabilities across two primary and two secondary school grades in Australia. It is the first longitudinal twin project of its kind in Australia and comprises a sample of 2762 twin pairs, 40 triplet sets and 1485 nontwin siblings. Measures include standardized literacy and numeracy test data collected at Grades 3, 5, 7 and 9 as part of the National Assessment Program: Literacy and Numeracy. A range of demographic and behavioral data was also collected, some at multiple longitudinal time points. This article outlines the background and rationale for the study and provides an overview for the research design, sample and measures collected. Findings emerging from the project and future directions are discussed.
Associations between selected dietary behaviours and academic achievement: A study of Australian school aged children
(Elsevier BV, 2017-09-01)
Burrows, Tracy
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Goldman, Sharni
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Olson, Richard K
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Byrne, Brian
;
Coventry, William L
Background: Research investigating the effects of dietary behaviours on children's academic achievement has predominately focused on breakfast consumption. The aim of this study was to conduct secondary analysis to examine associations between a range of dietary behaviours and children's academic achievement.
Methodology: Data on five dietary variables (fruit intake; vegetable intake; consumption of takeaway; sugar sweetened beverages; and breakfast) and scores in the five domains of a standardised academic achievement test known as NAPLAN (reading, writing, grammar/punctuation, spelling and numeracy) were obtained for Australian children aged 8–15 years in school grades three (n = 1185), five (n = 1147), seven (n = 1053) and nine (n = 860). Mixed linear models adjusted for socioeconomic status and gender were used to examine associations between dietary behaviours and academic scores.
Results: Greater consumption of vegetables with the evening meal (7 nights/week) was associated with higher test scores in the domains of spelling and writing (p=<0.01), with the greatest effect observed for spelling with a mean score difference of 86 ± 26.5 NAPLAN points between the highest and lowest levels of consumption (95% CI: 34.0–138.1; p=<0.01). Increased consumption of sugar sweetened beverages was associated with significantly lower test scores in reading, writing, grammar/punctuation and numeracy (<0.01).
Principle conclusions: The findings of this study demonstrate dietary behaviours are associated with higher academic achievement. Future research should further explore relationships between a wide range of dietary behaviours and children's academic achievement.
Comment on Asbury and Wai (2019), "Viewing Education Policy through a Genetic Lens," Journal of School Choice
(Routledge, 2020)
Byrne, Brian
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Little, Callie W
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Olson, Richard K
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Larsen, Sally A
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Coventry, William L
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Weymouth, Rachel
Asbury and Wai (Journal of School Choice, 2019) perform a valuable service by summarizing much available behavior–genetic research on academic achievement. However they consider that no specific policies stem from the research body at this time. Here we do propose a policy based on some of our research using twins, namely that available funding for students struggling with learning to read be targeted to them individually rather than allocated to schools per se. We briefly canvass some practical issues, such as the variety of funding mechanisms, best-practice intervention techniques, and identification of struggling readers. We also outline a general research strategy for uncovering factors contributing to educational attainment that takes behavior-genetic research as its starting point and drills down from there, and advocate including genetically-sensitive methods in a growing list of quantitative research techniques in education.
A Cross-Lagged Model of the Development of ADHD Inattention Symptoms and Rapid Naming Speed
(Springer New York LLC, 2012)
Arnett, Anne B
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Pennington, Bruce F
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Willcutt, Erik
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Dmitrieva, Julia
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Byrne, Brian J
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Samuelsson, Stefan
;
Olson, Richard K
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.
Differential Influences of Genes and Environment Across the Distribution of Reading Ability
(Springer New York LLC, 2019-08-05)
McGowan, Dipti
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Little, Callie W
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Coventry, William L
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Corley, Robin
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Olson, Richard K
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Samuelsson, Stefan
;
Byrne, Brian
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.
Does the Environment Have an Enduring Effect on ADHD?: A Longitudinal Study of Monozygotic Twin Differences in Children
(Springer New York LLC, 2016)
Livingstone, Luisa T
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Coventry, William L
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Corley, Robin P
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Willcutt, Erik G
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Samuelsson, Stefan
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Olson, Richard K
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Byrne, Brian J
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.
Dynamic and Static Assessment of Phonological Awareness in Preschool: A Behavior-Genetic Study
(Sage Publications, Inc, 2011)
Coventry, William L
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Byrne, Brian J
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Olson, Richard K
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Corley, Robin
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Samuelsson, Stefan
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 child’s current level of PA such as blending and elision, and the dynamic test included instruction in phoneme identity to assess the child’s 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.
Estimating classroom-level influences on literacy and numeracy: A twin study
(American Psychological Association, 2020-08)
Grasby, Katrina L
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Little, Callie W
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Byrne, Brian
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Coventry, William L
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Olson, Richard K
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Larsen, Sally
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Samuelsson, Stefan
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.
Evolutionary and Genetic Perspectives on Educational Attainment
(Emerald Group Publishing Limited, 2010)
Byrne, Brian J
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Khlentzos, Drew M
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Olson, Richard K
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Samuelsson, Stefan
At first glance, it may seem unusual to find a chapter on evolutionary psychology and genetics in a handbook of educational psychology, let alone open it. However, we hope to demonstrate why educators can benefit from being aware of work in these areas. Human biology may seem far removed from the day-to-day concerns of teachers and policy makers, but in one way or another evolutionary and genetic perspectives on education raise questions about many of these daily concerns and also suggest answers to at least some of them. For example: • Why is motivating students to listen to their teachers more of a problem than persuading them to believe their teachers? • Why might students of physics be more adept at reasoning about the motion of particles than solid bodies? • In a crowded school curriculum, what subjects should be given priority? • Why do children find it easier to learn to talk than to read, when the rules of grammar are seemingly so complex and the rules relating print to speech seemingly so straightforward? • Because reading difficulties are known to run in families, shouldn't parents foster literacy in the home earlier and more intensively? • Why are some children high (or low) achievers across a broad range of subjects, such as reading and mathematics, when the subject contents are so diverse? We begin by considering evolutionary perspectives on educational attainment before turning to the contribution of genetics to this area. In doing so, we draw on two branches of modern psychological science, evolutionary psychology and behavioural genetics.
Exploring the Influence of Early Childhood Education and Care on the Etiology of Achievement
(Springer New York LLC, 2020-11)
Little, Callie W
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Larsen, Sally
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Byrne, Brian
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Logan, Jessica A R
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Olson, Richard K
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Coventry, William L
The present study used a genetically-sensitive quantile regression approach to examine the relation between participation in early childhood education and care (ECEC) and subsequent school performance in literacy and numeracy at grades 3, 5, 7, and 9. The sample consisted of 1255 twin pairs (596 MZ; 659 DZ) with information on both ECEC and the National Assessment Program-Literacy and Numeracy (NAPLAN) scores from the Twin Study of NAPLAN. Results indicated variation in heritability estimates across the distributions of achievement, suggesting that different patterns of etiological influences may exist among children of different ability levels. Additionally, the results provided no evidence that ECEC significantly influenced achievement, and in the genetically-sensitive analyses, no evidence that ECEC moderated the influences of heritability of achievement for typically advantaged children. These results suggest that ECEC may not provide the levels of environmental support for later achievement that advocates claim, although we acknowledge that ECEC quality, which was not measured in the current study, may make a difference in whether or not ECEC influences achievement.
Gene-Environment Interactions in ADHD: The Roles of SES and Chaos
(Springer New York LLC, 2018)
Gould, Karen
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Coventry, William L
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Olson, Richard K
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Byrne, Brian J
Although attention-deficit/hyperactivity disorder (ADHD) is highly heritable, emerging evidence suggests symptoms are associated with interactions between genes and the environment (GxE) during development. This study tested whether heritability of ADHD symptoms is moderated by two environmental factors: socioeconomic status (SES) and chaos (household disorganisation). A population sample of 520 twin pairs (N = 1040, 52.3% female) from 6 to 15 years completed measures of behavior and home environment. Structural equation modelling was then used to test whether environmental factors were associated with a change in the extent to which genes explain variability in ADHD symptoms. Neither chaos nor SES moderated heritability, with consistent contributions from both genes and environment indicated across socioeconomic strata and levels of chaos. This finding contrasts with those of previous research, underlining the need to replicate results in the emerging field of GxE research across different populations and statistical methods. Robust findings may assist in developing targeted interventions for genetically vulnerable individuals.
The genetic and environmental etiologies of individual differences in early reading growth in Australia, the United States, and Scandinavia
(Academic Press, 2013)
Christopher, Micaela E
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Hulslander, Jacqueline
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Byrne, Brian J
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Samuelsson, Stefan
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Keenan, Janice M
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Pennington, Bruce
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DeFries, John C
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Wadsworth, Sally J
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Willcutt, Erik
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Olson, Richard K
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.
Genetic and Environmental Influences on Inattention, Hyperactivity-Impulsivity, and Reading: Kindergarten to Grade 2
(Routledge, 2010)
Ebejer, Jane
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Coventry, William L
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Byrne, Brian J
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Willcutt, Erik G
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Olson, Richard K
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Corley, Robin
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.
Genetic and Environmental Influences on Literacy and Numeracy Performance in Australian School Children in Grades 3, 5, 7, and 9
(Springer New York LLC, 2016)
Grasby, Katrina
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Coventry, William L
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Byrne, Brian J
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Olson, Richard K
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Medland, Sarah E
We examined the extent to which genes and the environment contributed to variation in and covariation among reading, spelling, grammar and punctuation, writing, and numeracy in Australian school children in Grades 3, 5, 7, and 9. Heritability was generally high: reading .58-.71 (excepting Grade 5 girls), spelling .68-.78; grammar and punctuation .52-.66, writing .39-.52, and numeracy .39-.79. Boys' performance varied more than girls in spelling and numeracy, and the common environment was a greater influence in girls than boys in Grade 3 numeracy and Grade 5 reading. Independent pathway models showed similar genetic and environmental structures at each grade with approximately one third to one half of the variation in each domain due to genes that influenced all domains. The covariation among the domains was largely mediated by genes. Results suggest substantial uniformity in the environmental factors influencing these academic domains.
Genetic and Environmental Influences on Vocabulary and Reading Development
(Routledge, 2011)
Olson, Richard K
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Keenan, Janice M
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Huslander, Jacquiline
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Byrne, Brian J
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Samuelsson, Stefan
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Coventry, William L
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Corley, Robin
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Wadsworth, Sally J
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Willcutt, Erik G
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DeFries, John C
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Pennington, Bruce F
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.
Heritability of High Reading Ability and its Interaction with Parental Education
(Springer New York LLC, 2009)
Friend, Angela
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DeFries, John C
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Keenan, Janice M
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Olson, Richard K
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Pennington, Bruce
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Harlaar, Nicole
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Byrne, Brian J
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Samuelsson, Stefan
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Willcutt, Erik G
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Wadsworth, Sally J
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Corley, Robin
Moderation of the level of genetic influence on children's high reading ability by environmental influences associated with parental education was explored in two independent samples of identical and fraternal twins from the United States and Great Britain. For both samples, the heritability of high reading performance increased significantly with lower levels of parental education. Thus, resilience (high reading ability despite lower environmental support) is more strongly influenced by genotype than is high reading ability with higher environmental support. This result provides a coherent account when considered alongside results of previous research showing that heritability for low reading ability decreased with lower levels of parental education.
Identical Genes, Unique Environments: A Qualitative Exploration of Persistent Monozygotic-Twin Discordance in Literacy and Numeracy
(Frontiers Research Foundation, 2019-03-21)
Larsen, Sally
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Byrne, Brian J
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Little, Callie
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Coventry, William
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Ho, Connie S
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Olson, Richard K
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Stevenson, Annette C
This study aimed to explore unique environmental factors impacting differential academic trajectories among Australian school students. Monozygotic (MZ) twin pairs who were consistently discordant in results of nationwide standardized tests of reading, numeracy or writing between Grades 3 and 9 were identified. MZ twins control for genes, gender, age, and aspects of the home and school environment shared by twins. Thus, any difference between MZ twins in academic outcomes can be attributed to the unique environment experienced by each twin. From 551 MZ twin pairs with three or four sets of test results, we identified 55 pairs who were substantially and consistently discordant in reading, numeracy or writing between Grades 3 and 9. Parents were contacted for interview, resulting in 40 semi-structured interviews. Qualitative data analysis revealed three major themes, interpreted by parents as possible contributors to persistent academic discordance: biological mechanisms, school-based factors, and personal factors. We discuss implications for educational practice, policy, and research.
Individual Prediction of Dyslexia by Single Versus Multiple Deficit Models
(American Psychological Association, 2012)
Pennington, Bruce F
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Santerre-Lemmon, Laura
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Olson, Richard K
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Rosenberg, Jennifer
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MacDonald, Beatriz
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Boada, Richard
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Friend, Angela
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Leopold, Daniel R
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Samuelsson, Stefan
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Byrne, Brian J
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Willcutt, Erik G
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 individual's 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.
Little Evidence That Socioeconomic Status Modifies Heritability of Literacy and Numeracy in Australia
(Wiley-Blackwell Publishing, Inc, 2019-03)
Grasby, Katrina L
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Coventry, William L
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Byrne, Brian
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Olson, Richard K
Socioeconomic status (SES) has been found to moderate the influence of genes and the environment on cognitive ability, such that genetic influence is greater when SES is higher, and the shared environment is greater when SES is lower, but not in all Western countries. The effects of both family and school SES on the heritability of literacy and numeracy in Australian twins aged 8, 10, 12, and 14 years with 1,307, 1,235, 1,076, and 930 pairs at each age, respectively, were tested. Shared environmental influences on Grade 3 literacy were greater with low family SES, and no other moderating effects of SES were significant. These findings are contrasted with results from the United States and the United Kingdom.
The longitudinal perspective on developmental disorders
(Psychology Press, 2013)
Byrne, Brian J
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Olson, Richard K
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Samuelsson, Stefan
In this chapter we used developmental dyslexia to exemplify the value of employing longitudinal designs in research on developmental disorders. We show that a full understanding of dyslexia, its characteristics, its causes, and its treatment, depends on studying it longitudinally, and failing to do so would lead to an impoverished account of the disorder. We also make reference to other disabilities as a way of testing the generality and value of our conclusions from dyslexia.

Browsing by Author "Olson, Richard K"

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