admittedly selective compilation of illustrative G × E findings is exactly what is appropriate at the present time. This would seem especially so in light of the fact that almost all the available human G × E research focuses on both a restricted range of environments, typically emphasizing the negative end of the spectrum and failing to measure at all the positive (except for the absence of adversity), and a restricted range of psychological and behavioral outcomes, also typically emphasizing the negative, thereby failing to assess competent functioning (except for the absence of dysfunction). As a result of these design characteristics of so many G × E investigations, it remains unknown whether extensive evidence consistent with a diathesis–stress model and seemingly inconsistent with a differential-susceptibility framework is an accurate reflection of G × E processes or an artefact of study designs. Quite conceivably, simply treating the absence of adversity as the ‘good' end of the environmental-exposure continuum and/or absence of a disorder as the ‘good' end of the psychological functioning continuum may lead to the under-detection of differential-susceptibility findings and an over representation of vulnerability ones. It is for these reasons that it is considered appropriate at the present time
