The diathesis–stress and bioecological models of G × E thus represent fundamentally different models of G × E. Under the diathesis–stress model, G × E would manifest as stronger genetic effects in the presence of environmental risk. In more specific terms, the diathesis–stress model would predict absolute (or unstandardized) increases in genetic influences with increasing environmental risk exposure. There are no clear predictions for environmental influences on the outcome. Under the bioecological model, by contrast, deleterious environments are thought to amplify (shared) environmental influences, whereas genetic influences are more important under normal environmental conditions. In this case, the model would specifically predict absolute increases in environmental influences with increasing environmental risk exposure. Genetic influences on the outcome would be expected to decrease. However, the latter effect may only be observable when examined relative to the environmental moderation (i.e. via standardized estimates): ‘unlike in a diathesis–stress model, the environmental factor in a bioecological interaction does not necessarily act on the same biological substrate as the genetic risk factors. Instead, it may just allow those genetic risk factors to account for more
