UC Davis

It is widely appreciated that individuals vary in the extent to which developmental experiences and exposures shape their development. Individual differences in developmental plasticity have been highlighted in at least two different conceptual models—the diathesis-stress/dual-risk model which suggests that some individuals are more vulnerable to the negative effects of contextual adversity (Monroe & Simmons, 1991; Zuckerman, 1999)—and the differential susceptibility model which stipulates that individuals are developmentally plastic, and therefore vary more generally in their susceptibility to environmental effects both positive and negative (Belsky, Bakermans-Kranenburg & van Ijzendoorn, 2007; Ellis et al., 2011). Although much of the research on developmental plasticity is often cast in trait-like terms (Boyce & Ellis, 2005; Aron & Aron, 1997), there is also evidence that suggests otherwise (Belsky & Beaver, 2011; Belsky et al., 2021; Zhang, Widamen, & Belsky, 2021). Moreover, what remains to be further investigated is whether differential susceptibility is domain-general (i.e., trait-like) or domain-specific (Belsky et al., 2021).The current dissertation extends research on differential susceptibility in terms of domain-general versus domain-specific developmental plasticity by exploring susceptibility to (a) parenting and peers, and (b) early-life adversity in the form of threat and deprivation. Paper 1 examines the interrelation of individual differences in susceptibility to parenting and peer effects. Paper 2 does the same with respect to effects of deprivation and threat in early life. Overall, this dissertation provides further evidence for individual differences in terms of domain-general versus domain-specific developmental plasticity.