Psychogenetic study of language competence’s structure

Abstract

The aim of research is study of structure of interrelations between some language abilities in younger school age. The classical method of twins is used. The phenotypic, genetic and environmental correlations between the subtests of the Heidelberg test of language development are estimated. The previously obtained results of studying of the role of genetic and environmental factors in the etiology of individual differences in language characteristics are used. The sample is 35 monozygotic and 33 dizygotic same-sex twin pairs aged between 7 and 8 years 11 months; among them – 36 pairs of girls and 32 pairs of boys. The control sample consisted of 53 children of the same age; among them – 26 girls and 27 boys. The structure of phenotypic correlations indicates that language skills related to the grammar, morphology, syntax, semantics spheres constitute a relatively common "language" factor named language competence. Abilities related to visual-figurative thinking, understanding and using a language for pragmatic purposes, poorly correlate with each other and other Heidelberg test’s subtests. They are manifestations of other spheres of personality, indirectly related to language. The pattern of correlations reproduced on the twins’ sample and sample of the single born children. There are found that significant correlations between Heidelberg test’s subtests, on average, 40% are attributable to common genetic influences. The sixth part of the covariation of language competence’s characteristics is explained by environmental (mainly – shared) effects. The results are important to clarify the etiology of the structure of language characteristics in native Russian speakers.