Evolutionary-biological reasoning suggests that individuals should be differentially susceptible to environmental influences, with some people being not just more vulnerable than others to the negative effects of adversity, as the prevailing diathesis-stress view of psychopathology (and of many environmental influences) maintains, but also disproportionately susceptible to the beneficial effects of supportive and enriching experiences (or just the absence of adversity). Evidence consistent with the proposition that individuals differ in plasticity is reviewed. The authors document multiple instances in which (a) phenotypic temperamental characteristics, (b) endophenotypic attributes, and (c) specific genes function less like “vulnerability factors” and more like “plasticity factors,” thereby rendering some individuals more malleable or susceptible than others to both negative and positive environmental influences. Discussion focuses upon limits of the evidence, statistical criteria for distinguishing differential susceptibility from diathesis stress, potential mechanisms of influence, and unknowns in the differential-susceptibility equation.

Students of human development appreciate that individuals vary in whether and/or the degree to which they are affected, over the shorter and longer term, by environmental experiences, including child-rearing ones. Perhaps the most striking evidence that person characteristics condition or moderate environmental effects is to be found in developmental research on Temperament × Parenting interaction (Rothbart & Bates, 2006) and psychiatric research on Gene × Environment interaction (GXE; Burmeister, McInnis, & Zollner, 2008).

Work in both these areas of inquiry is guided primarily, even if not exclusively, by what developmentalists regard as the transactional/dual-risk model (Sameroff, 1983) and what psychiatrists and others studying and treating psychopathology regard as the diathesis-stress model (Monroe & Simons, 1991; Zuckerman, 1999). Central to both these frameworks is the view that...