Developmental stability of the relative influence of genes and environment on specific cognitive abilities during childhood.

Describes hierarchical multiple regression (HMR) model for analysis of cross-sectional data to examine developmental changes in the relative influence of genes and environment. The HMR model is advocated because it provides a test of significance for age changes without the loss of information and statistical power that results when continuous variables, such as age, are assigned to categories. This model was applied to 9 tests of specific cognitive abilities that were administered to 54 identical and 33 same-sex fraternal twin pairs whose ages ranged from 5 to 11 yrs. Results indicate that familial influences as well as the relative mixture of genetic and environmental influences on specific cognitive abilities remain stable during this fast-moving developmental era. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)