Genetic and environmental influences on two measures of speed of information processing and their relation to psychometric intelligence: Evidence from the German observational study of adult twins
Ac. Neubauer et al., Genetic and environmental influences on two measures of speed of information processing and their relation to psychometric intelligence: Evidence from the German observational study of adult twins, INTELLIGENC, 28(4), 2000, pp. 267-289
Speed of information processing, as measured by reaction times (RTs) in ele
mentary cognitive tasks (ECTs), has been found to be an important correlate
of human psychometric intelligence. While the heritability of psychometric
intelligence is well understood, we know only a little about genetic and e
nvironmental influences on ECT performance, particularly about genetic and
environmental contributions to ECT-intelligence relation. These questions w
ere studied by employing two widely used ECTs (Sternberg's memory scanning
and Posner's letter-matching task) as well as two psychometric intelligence
tests (Advanced Progressive Matrices and Leistungs-Pruf System) in a large
sample of 169 monozygotic (MZ) and 131 dizygotic (DZ) twin pairs. As expec
ted, RTs correlated negatively with psychometric intelligence. Moreover, he
ritability estimates were substantial for both psychometric intelligence an
d RTs in ECTs. Finally, multivariate genetic analyses suggested that most o
f the phenotypic correlation between mental speed and intelligence is due t
o genetic factors.