Differential susceptibility to the environment: Toward an understanding of sensitivity to developmental experiences and context

Science, like evolution, is often remarkably convergent in itsgenerativityofnewideasanditsexplorationofnovelconcep-tualterritory.Justasevolutionhasrepeatedlyconvergeduponcommon phenotypic solutions to problems of survival andreproduction among species of differing lineage (Morris,2010), the history of scientific inquiry, and that of develop-mentalscienceinparticular,hasalsobeenmarkedbyconcur-rent and homologous discovery by a sometimes striking si-multaneity in its arrival at shared theoretical insights alongpaths of differing origins and trajectories. Thus, it has beenwith the emergence of “differential susceptibility to the envi-ronment”: a construct—really, a shared solution to a set ofcompelling conceptual and empirical dilemmas—that formsthe centerpiece of this Special Section of Development andPsychopathology.Inspired by a provocative and broadly attended sympo-sium (“Do Children Vary in Their Plasticity? DifferentialSusceptibility to Rearing Experiences”) at the 2009 AnnualMeeting of the Society for Research in Child Development(SRCD), the Special Section explores the convergence oftwo theories conceptualizing reactivity to environmentalstimuli as an indicator of sensitivity or susceptibility to envi-ronmental influence. The “biological sensitivity to context”theory advanced by Boyce and Ellis (2005; see also Boyceet al., 1995) originated in empirical observations of differ-ences in children’s autonomic and adrenocortical reactivityto challenge and posited a context-sensitive endophenotyperendering a subset of children unusually susceptible to therisk-inducing and development-enhancing influences of bothnegative and positive early social environments. At the sametime, the “differential susceptibility” theory posed by Belsky(1997,2005)startedwiththequestion“Whyshouldchildhoodexperiences influence later development? ” Based on reflec-tions prompted by this question, it hypothesized that childrenshould differ in their susceptibility to rearing environments asabet-hedgingstrategyagainstanuncertainfuture.Boththeoriesconverged on evolutionaryexplanationsofwhyandhow indi-viduals vary systematically in their sensitivity or “permeabil-ity” to experiential and contextual influences on developmentand health.Moststudentsofchilddevelopmentdonotpresumethatallchildrenareequallysusceptibletorearingandothercontextualexperiences; a long history of research on Parenting Temp-erament interactions clearly suggests otherwise. Nevertheless,muchworkstillfocusesoncontextualeffectsthatapplyequallyto all children and thus fails to consider the possibility thatwhether, how, and to what degree early experiences influencechilddevelopmentmaycriticallydependuponindividualchar-acteristics. All four empirical papers presented at the SRCDsymposiumexaminedtheextenttowhichsuchchildcharacter-istics moderate effects of early rearing experiences on chil-dren’s adjustment and development. Drawing on biologicalsensitivity to context or differential susceptibility theory, eachpaper focused on a phenotypic, endophenotypic, or genotypicmarker of reactivity as a moderator of susceptibility to rearinginfluence. In the first two papersthe moderator was biological