As individuals leave the home environment in adolescence and adulthood, it is more likely that unique environments, as opposed to that shared with his or her siblings, will have an impact on personality (Bouchard & Loehlin, 2001). Gene-by-nonshared environment interaction has the effect of making genetically similar individuals less similar, and therefore genetic effects become tied to unique environmental variation. In other words, the effects of gene-by-nonshared environment interaction contribute to the estimate of nonshared environmental influences when not explicitly modeled (Purcell, 2002). In this case, nonshared environmentality would be expected to rise as individuals mature and leave the shared home environment. Again, such interactions may be recurring, lasting, or fleeting. If they are recurring or lasting, this would result in stable nonshared environmental influences. If they are fleeting, this would result in unstable nonshared environmental influences.
