1993'5, p.106
Egorova M. S. , Zyryanova N. M. , P'yankova S. D.
Age-specific changes in genotype-environ connections to mental abilities

The results of longitudinal twin study are presented. MZ and DZ twins were examinated in senior preschool age, after one year of school education and after three years of school education. The changes in verbal, non-verbal and general intellect, connected to age, between MZ and DZ twins were found to depend upon environment rather than upon heredity.