Genetic analysis of general intelligence ‘g’: A twin study

A sample of 30 MZ and 30 DZ twins reared together matched on age, educational standard and sex (i.e. male) and other background factors was selected from rural areas of Haryana (India). Subjects were administered Ravenʹs Standard Progressive Matrices (SPM) as a measure of ‘g’ to determine its heritability. The Falconerʹs heritability (h2) was 0.81, whereas the common family environment was 0.089. The findings have been discussed in the light of distinct background factors of the sample. Results add to the generality of the inheritance of general intelligence.