Which of the following options will correspond to the lowest coefficient of correlation with reference to the hereditary influences on intelligence?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Brothers and sisters reared together
Studies of twins and siblings show that the closer the hereditary link, the higher the correlation between their intelligence scores:
identical twins reared together — almost 0.90 (Option 4);
identical twins reared in different environments — 0.72 (Option 1);
fraternal twins reared together — almost 0.60 (Option 2);
brothers and sisters reared together — about 0.50 (Option 3).
Of the four options, brothers and sisters reared together have the lowest correlation. (Siblings reared apart correlate still lower, about 0.25, but they are not among the options.)
NCERT (2025-26): “Intelligence: Interplay of Nature and Nurture The evidence for hereditary influences on intelligence comes mainly from studies on twins and adopted children. The intelligence of identical twins reared together correlate almost 0.90. Twins separated early in childhood also show considerable similarity in their intellectual, personality and behavioural characteristics. The intelligence of identical twins reared in different environments correlate 0.72, those of fraternal twins reared together correlate almost 0.60, and those of brothers and sisters reared together correlate about 0.50, while siblings reared apart correlate about 0.25.…” |