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A TWIN STUDY OF GENETIC INFLUENCES ON READING AND SPELLING ABILITY AND DISABILITY
Author(s) -
Stevenson Jim,
Graham Philip,
Fredman Glenda,
Mcloughli Vivienne
Publication year - 1987
Publication title -
journal of child psychology and psychiatry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.652
H-Index - 211
eISSN - 1469-7610
pISSN - 0021-9630
DOI - 10.1111/j.1469-7610.1987.tb00207.x
Subject(s) - spelling , psychology , concordance , reading (process) , developmental psychology , reading disability , twin study , heritability , dyslexia , dizygotic twins , population , intelligence quotient , cognition , genetics , demography , linguistics , psychiatry , medicine , philosophy , obstetrics , sociology , biology
The reading skills of 285 pairs of 13‐year‐old twins drawn from the general population were studied. The twins were independently tested using standardized measures of intelligence, reading and spelling ability. The genetic contribution to reading ability was assessed by examination of correlations in monozygotk: (MZ) and student‐sex dizygotic (DZ) twins, and by analysing differences bi Mccen MZ and DZ twins in concordance of reading disability rates. The results suggested that, at this age, genetic factors play only a moderate role in general reading backwardness or specific reading retardation. However, when spelling ability was investigated, a heritability of 0.53 was obtained, increasing to 0.75 when intelligence was controlled. Strong genetic influences on spelling were also found when concordance rates for spelling disability were compared for MZ and DZ pairs.