More recently, an alternative framework has been proposed by Belsky and colleagues—the differential susceptibility hypothesis—in which the same individuals who are most adversely affected by negative environments may also be those who are most likely to benefit from positive environments. Rather than searching for “vulnerability genes” influencing psychiatric and behavioral outcomes, they propose the idea of “plasticity genes,” or genes involved in responsivity to environmental conditions (Belsky et al. 2009). Belsky and colleagues reviewed the literatures surrounding gene-environment interactions associated with three widely studied candidate genes, MAOA, 5-HTT, and DRD4, and suggested that the results provide evidence for differential susceptibility associated with these genes (Belsky et al. 2009). Their hypothesis is closely related to the concept of biological sensitivity to context (Ellis & Boyce 2008). The idea of biological sensitivity to context has its roots in evolutionary developmental biology, whereby selection pressures should favor genotypes that support a range of phenotypes in response to environmental conditions because this flexibility would be beneficial from the perspective of survival of the species. However, biological sensitivity to context has the potential for both
