Human behavioral flexibility: a psychogenetic study.

Forty-seven two-children families from Moscow were used in a study to assess genetic determination of behavior flexibility, which was measured by eight laboratory tests. Flexibility is regarded as a temperament trait. There was no age- or sex-specific differentiation of human behavioral flexibility. Genetic determination of indices was used as a criterion for construct validization of flexibility tests. Factor analysis produced two principal components of flexibility: "operational flexibility" and "afferent flexibility." The study showed that a considerable part of the phenotypic variability of the flexibility indices included in different factors is under approximately equal genetic control. The flexibility factors differ in their genetic determination. In the inheritance of the first factor the leading role belongs to the additive component, whereas the dominance effects are more prominent in the second factor of flexibility.