David Hay|Pauline J. O'Brien|Carol Johnston|Margot Prior
The High Incidence of Reading Disability in Twin Boys and Its Implications for Genetic Analyses
La Trobe University
1975 australian council educational research acer conducted nationwide survey literacy numeracy 10 14year olds total 297 12875 children involved twins age 14 42 twin boys achieved adequate standards literacy compared 71 singleborn boys deficit twin girls much less twins sexes moderately behind numeracy survey 913yearold twin boys la trobe twin study lts produced similar results 75 average reading skills 23 behind 18 months despite average iqs acer data corroborated teachers reports obtained survey indicate also twins problems receiving remediation high incidence classroom problems spelling reading reversals pattern mistakes twins make specific items acer survey explained resulting either specific cognitive deficits problems concentration factors influence performance different tasks literacy numeracy much closely interrelated twins singletons also correlate measure verbal intelligence implications genetic analysis scholastic achievement examined centering around different factor structure abilities twins common family environmental effects unique twins