Thesis (Ph.D.) - Indiana University, School of Education, 2009The current study utilizes data from the National Institute of Child Health and Human Development Study of Early Child Care and Youth Development (Research Triangle Institute, 2002) to explore the moderating effect of infant emotionality (i.e., emotional intensity and negative mood) on maternal emotional support (i.e., responsivity and rejection) during early childhood predicting childhood levels of reactivity and effortful control. A primary aim of the current investigation was to determine if moderated effects were better accounted for by one of two explanatory models: gene-environment dual risk vulnerability or differential susceptibility. Predicting later levels of childhood reactivity, infants with high levels of emotional intensity were more vulnerable to maternal rejection than infants with low levels of emotional intensity. Predicting later levels of childhood reactivity and effortful control, infants with high levels of negative mood were more vulnerable to maternal rejection than infants with low levels of negative mood. The above findings are in support of gene-environment dual risk vulnerability. Findings are discussed in light of other results in support of differential susceptibility, as well as limitations to the current study and areas of future research.