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FURTHER EVIDENCE FOR GENETIC INFLUENCES ON EDUCATIONAL ACHIEVEMENT
Author(s) -
GILL C. E.,
JARDINE R.,
MARTIN N. G.
Publication year - 1985
Publication title -
british journal of educational psychology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.557
H-Index - 95
eISSN - 2044-8279
pISSN - 0007-0998
DOI - 10.1111/j.2044-8279.1985.tb02629.x
Subject(s) - variation (astronomy) , psychology , developmental psychology , population , heritability , twin study , test (biology) , nature versus nurture , variance (accounting) , aptitude , demography , social psychology , evolutionary biology , genetics , biology , ecology , sociology , physics , accounting , astrophysics , business
S ummary . A genetic analysis of Tertiary Admission Examination (TAE) and Australian Scholastic Aptitude Test (ASAT) results for 264 pairs of MZ and DZ twins is reported. Purely environmental models are rejected as inadequate explanations of variation in examination performance and genetic factors must be invoked to obtain a satisfactory fit to the data. Within the portion of the age cohort who are candidates for these examinations, genetic factors appear to account for about 70 per cent of variation while environmental experiences shared by siblings appear to have little or no influence. However, when corrections are made on the assumption that examination candidates represent the top 34 per cent from a normal distribution of ability in the population, much greater variation between families is inferred for the population. If we also take account of the high correlation in educational achievement between husbands and wives the putative population twin correlations are consistent with heritabilities between 0.6 and 0.7 and modest contributions of shared environment around 20 per cent of the total variance. The data suggest that a distinction between IQ tests and tests of scholastic achievement on the basis of their causes of variation is not justified. We also show that while a common genetic factor is responsible for much of the covariation of ASAT Arts and Science scores, there are also some differences in the genes responsible for variation in the two areas.