PhD Oral Exam - Melissa Commisso, Psychology

When studying for a doctoral degree (PhD), candidates submit a thesis that provides a critical review of the current state of knowledge of the thesis subject as well as the student’s own contributions to the subject. The distinguishing criterion of doctoral graduate research is a significant and original contribution to knowledge.

Once accepted, the candidate presents the thesis orally. This oral exam is open to the public.

Abstract

Social isolation in youth is a significant concern driving researchers to identify the risk and protective factors that shape its experience and outcomes. While isolation is experienced at the individual level, it is also shaped by broader social systems that the individual is embedded in. Examination of buffering factors requires a socio-ecological approach that considers these systems. The overarching goal of this dissertation was to adopt an ecological and process-oriented approach in identifying moderators of the stability of social isolation and its consequences across three levels of social complexity: the individual, the dyad and the group. Study 1 used a sample of youth from Montreal, Canada and Barranquilla, Colombia to examine whether being friended buffered associations between individual-level active (other-inflicted) and passive (self-inflicted) forms of isolation and trajectories of depressed affect. It further examined whether the effects of friendship varied according to peer-group characteristics including group-level active isolation, passive isolation, collectivism, individualism, gender, place and socio-economic status. The results showed that though friendship protected youth from the negative effects of active and passive isolation, the extent of this protection depended on features of the group. The benefits were minimized in groups with high collectivism and passive isolation. Study 2 used the Actor-Partner Interdependence Model with best friend dyads to assess whether the stability of a child's levels of passive and active isolation was moderated by a best friend's level of peer acceptance. Findings revealed that having a well-accepted friend decreased active isolation across time. Study 3 examined the buffering effect of a positive social self-concept on the stability of discrimination-based peer exclusion in youth living in Colombia and the differential effects for Venezuelan refugee and Colombian-born children. Findings demonstrated that for Venezuelan refugee youth, but not Colombian youth, a positive social self-concept minimized increases in discrimination-based exclusion. Together, these studies provide insight into the complexity of social isolation as a multifaceted experience influenced by individual characteristics, dyadic relationships, and broader social contexts.