Gene-environment correlation in particular is a promising candidate for explaining increasing heritability with age (Scarr and McCartney 1983). Gene-environmental correlations are theorized to occur through three different processes: passive, active, and evocative. In the first type, a child’s genes and his or her environment are correlated because the parents providing the genes are also shaping the child’s environment. In active gene-environment correlation, the child is helping to create his or her environment through actively choosing activities or other factors which complement inherited capacities. Evocative gene-environment correlation occurs when genetically mediated traits in the child stimulates particular reactions in other people which again influence the child’s environment. Scarr and McCartney and others (McGue 2010; Rutter 2007) have proposed that increasing heritability with age may be related to the increasing ability of a child to choose their own environment as they mature and gain autonomy, and thus the increasing contribution of active gene-environment correlations to heritability values.
