Although a number of papers report changes in heritability, these are often misleading. The heritability is the proportion of phenotypic variance due to genetic influences, and can change as the result of a moderation of genetic variance, shared environment variance, non-shared environment variance, or any combination of these. Therefore, it is possible for the heritability to change, even when the genetic variance remains constant. Moreover, it is even possible for the genetic variance to increase while the heritability decreases. Consequently, only changes in absolute variances were reported in the current paper.
