It is also important to note that genetic and environmental influences are not necessarily independent factors. That is to say that although some environmental influences may be largely random, such as experiencing a natural disaster, many environmental influences are not entirely random (Kendler et al. 1993). This phenomenon is called gene-environment correlation. Three specific ways by which genes may exert an effect on the environment have been delineated (Plomin et al. 1977, Scarr & McCartney 1983): (a) Passive gene-environment correlation refers to the fact that among biologically related relatives (i.e., nonadoptive families), parents provide not only their children’s genotypes but also their rearing environment. Therefore, the child’s genotype and home environment are correlated. (b) Evocative gene-environment correlation refers to the idea that individuals’ genotypes influence the responses they receive from others. For example, a child who is predisposed to having an outgoing, cheerful disposition might be more likely to receive positive attention from others than a child who is predisposed to timidity and tears. A person with a grumpy, abrasive temperament is more likely to evoke unpleasant responses from coworkers
