In behaviour genetics, an examination of the correlation between monozygotic twins, and sometimes a comparison with the correlation between dizygotic twins, on a measurable trait in order to estimate the heritability of that trait, the assumption being that the higher the heritability of the trait the greater will be the correlation between monozygotic twins and the more it will differ from the correlation between dizygotic twins, because monozygotic twins share identical genes and should therefore be more alike on a heritable trait than dizygotic twins who share only about half their genes in common. It can be shown mathematically that a rough estimate of heritability is provided by twice the difference between the monozygotic-twin and dizygotic-twin correlations. See also DF extremes analysis. Compare adoption study, kinship study.
Subjects: Sports and Exercise Medicine — Psychology.