abstract: The current study examined the unique influence of emotional childhood abuse on positive and negative aspects of different types of social relationships (e.g., family, spouse/partner, and friends) in midlife and whether genetic variations of the oxytocin receptor gene (OXTR) moderated these associations. Genetic variations in OXTR are measured by single-nucleotide polymorphisms (SNPs), which have been the most substantially studied prospects for explaining individual differences in socio-behavioral phenotypes. Specifically, an SNP, rs53576, involving a guanine (G) to adenine (A) substitution located in the third intron of the OXTR has been associated with fundamental aspects of social processes and behaviors. Compared to A carriers, individuals homozygous for the G allele have enhanced social competencies and tend to elicit more positive responses from social partners, consequently increasing the overall quality of social relationships across the lifespan. However, the G allele of the OXTR has also been associated with greater social sensitivity. In the current study, conducted among a sample of 614 adults in midlife, it was shown that emotional childhood abuse was significantly associated with having less supportive and more strained relationships in midlife. Regarding supportive family relationships, the effect of emotional childhood abuse was moderated by the OXTR rs53576 polymorphism. Specifically, under conditions of more emotional abuse in childhood, individuals homozygous for the G allele had more supportive family relationships in midlife compared to A carriers. Overall, the findings suggest that genetic variations of OXTR rs53576 may be an important candidate in understanding the development of social relationship functioning within the context of negative early life experiences. / Dissertation/Thesis / Masters Thesis Psychology 2018