Infant twins longitudinal study: Specificity of mental development

The longitudinal infant twin study was carried out firstly in Russian psych ology. Specific characteristics of mental and psychomotor development in tw ins from 3-4 to 42 months as well the factors of biological risk were discu ssed. Particularly, there have been found the differences in the rate and d uration of the compensation of risk factors in MZ and DZ twins. In the firs t three years the genetic contribution to general cognitive abilities was e valuated at the level 22%, and psychomotor development-18% but common envir onment contribution was more significant.