Abstract
Measures of word recognition (REC) and two component skills, phono- logical coding (PHON) and orthographic coding (ORTH), were subjected to multivariate behavioral genetic analysis. Data were obtained from a sample of identical and fraternal twin pairs wherein at least one member of each pair was reading disabled (RD), and from a sample of twins wherein both members of each pair read in the normal range. Confirmatory factor analysis was used to fit the genetic, common environmental, and specific environmental covariance components for REC, PHON, and ORTH within the RD and normal simples. The resulting heritability estimates for REC, PHON, and ORTH were 0.59, 0.41, and 0.05 in the RD sample, and 0.35, 0.52, and 0.20 in the normal sample. After dropping the nonsignificant common environment parameters from the models, the genetic correlations between REC and PHON and between REC and ORTH were respectively 0.81 and 0.45 in the RD sample, and 0.68 and 0.45 in the normal sample. Differences between the genetic correlations were significant in the RD sample (p < 0.005), marginally significant in the normal sample (p < 0.10), and highly significant in the combined sample (p < 0.001), indicating that genetic influences on individual differences in REC are more strongly related to genetic variance in PHON than in ORTH. These results are consistent with previous demonstrations of substantial genetic covariance between the disabled group’s deficits in REC and PHON, but not between REC and ORTH (Olson et al., 1989; Olson and Rack, 1990).
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References
Baron, J. 1977. Mechanisms for pronouncing printed words: use and acquisition. In D. Laberge and S. J. Samuels (Eds.), Basic processes in reading: perception and comprehension. Hillsdale, NJ. Erlbaum.
Cern. 1977. MINUIT: A system for Function Minimization and Analysis of Parameter Errors and Correlations, CERN, Geneva, Switzerland.
Coltheart, M. 1978. Lexical access in simple reading tasks. In G. Underwood (Ed.), Strategies of information processing. London: Academic Press.
Conners, F. and Olson, R. K. 1990. Reading comprehension in dyslexic and normal readers: A component-skills analysis. In D. A. Balota, G. B. Flores d’Arcais, and K. Rayner (Eds.), Comprehension processes in reading (pp. 557–579). Hillsdale, NJ: Erlbaum.
De Fries, J. C. 1985. Colorado reading project. In D. B. Gray and J. F. Kavanagh (Eds.), Biobehavioral measures of dyslexia (pp. 107–122). Parkton, MD: York Press.
De Fries, J. C. and Fulker, D. W. 1986. Multivariate behavioral genetics and development: An overview. Behavior Genetics, 16, 1–10.
De Fries, J. C. and Fulker, D. W. 1985. Multiple regression analysis of twin data. Behavior Genetics, 15, 467–473.
De Fries, J. C. and Fulker, D. W. 1988. Multiple regression analysis of twin data: Etiology of deviant scores versus individual differences. Acta Geneticae Medicae et Gemellologiae: Twin Research, 37, 205–216.
Dunn, L. M. and Markwardt, F. C. 1970. Examiner’s manual: Peabody Individual Achievement Test, Circle Pines, MN: American Guidance Service.
Fulker, D. W., Baker, L. A. and Bock, R. D. 1983. Estimating components of covariation using LISREL. Data Analysis, 1, 5–8.
Gillis, J. J., DeFries, J. C, Olson, R. K. and Rack, J. P. 1990. Confirmatory factor analysis of reading performance and process measures in the Colorado Reading Project. Behavior Genetics, 20 721 (Abstract).
Heath, A. C, Neale, M. C, Hewitt, J. K., Eaves, L. J. and Fulker, D. W. 1989. Testing structural equation models for twin data using LISREL. Behavior Genetics, 19, 9–35.
Nichols, R. C. and Bilbro, W. C. 1966. The diagnosis of twin zygosity. Acta Genetica, 16, 265–275.
Olson, R. K. and Rack, J. P. 1990. Genetic and environmental influences on component reading and language skills. Paper presented at the XVI International Rodin Remediation Scientific Conference on Genetic and Neurological Influences in Dyslexia, Boulder, Colorado, September 19-21, 1990.
Olson, R. K., Wise, B., Conners, F. and Rack, J. 1990. Organization, heritability, and remediation of component word recognition and language skills in disabled readers. In T. H. Carr and B. A. Levy (Eds.), Reading and its development: Component skills approaches (pp. 261–322). New York: Academic Press.
Olson, R. K., Wise, B., Conners, F., Rack, J. and Fulker, D. 1989. Specific deficits in component reading and language skills: Genetic and environmental influences. Journal of Learning Disabilities, 22, 339–348.
Plomin, R., De Fries, J. C. and McClearn, G. E. 1990. Behavioral Genetics: A Primer. New York: W. H. Freeman and Company.
Pennington, B. F. 1989. Using genetics to understand dyslexia. Annals of Dyslexia, 39, 81–93.
Schonell, F. J. 1971. Reading and Spelling Tests: Handbook of Instructions. Edinburgh: Oliver and Boyd.
Stanovich, K. E. 1988. Explaining the differences between the dyslexic and the garden-variety poor reader: the phonological-core variable-difference model. Journal of Learning Disabilities, 21, 590–612.
Stanovich, K. E. and West, R. F. 1989. Exposure to print and orthographic processing. Reading Research Quarterly, 24, 402–433.
Stevenson, J. (in press). Which aspects of processing text mediate genetic effects? Reading and Writing: An Interdisciplinary Journal.
Van Orden, G. C, Pennington, B. F. and Stone, G. O. 1990. Word identification in reading and the promise of subsymbolic psycholinguistics. Psychological Review, 97, 488–522.
Wechsler, D. 1974. Examiner’s manual: Wechsler Intelligence Scale for Children-Revised. New York: The Psychological Corporation.
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Olson, R.K., Gillis, J.J., Rack, J.P., Defries, J.C., Fulker, D.W. (1991). Confirmatory Factor Analysis of Word Recognition and Process Measures in the Colorado Reading Project. In: Pennington, B.F. (eds) Reading Disabilities. Neuropsychology and Cognition, vol 4. Springer, Dordrecht. https://doi.org/10.1007/978-94-011-2450-8_4
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DOI: https://doi.org/10.1007/978-94-011-2450-8_4
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