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Harvard Educational Review
September 1969, Vol. 39, No. 3, pp. 571-580

F. Fehr

The confounding of environmental and hereditary influences is a considerable problem in estimating heritability from twin studies. Fred S. Fehr discusses this problem and suggests two ways of calculating heritability which separate these influences more cleanly than the formula commonly used. The importance of heritability in the determination of intelligence is considerably less than suggested by Jensen when the effects of environmental variables are thus more adequately controlled.