Date of Graduation


Document Type


Degree Name

Doctor of Philosophy in Psychology (PhD)

Degree Level



Psychological Science


Ana J. Bridges

Committee Member

Lindsay S. Ham

Second Committee Member

Jacquelyn Wiersma-Mosley


adolescence, bystander intervention, high school students, interpersonal violence


Bystander approaches are promising interventions that can engage bystanders as prosocial allies to intervene in interpersonal violence situations among youth within school settings. The Mentors in Violence Prevention (MVP) bystander intervention program targets interpersonal violence using a peer-to-peer mentoring model to engage students in a discussion about violence prevention. Research on the MVP program is promising but limited. The current study examined the specificity of MVP intervention effects in two high school samples. The first was a pre/post-test design that included a smaller sample of high school students who participated in the MVP program in the 2013-2014 academic year. The second was a retrospective design that included a large, geographically diverse sample of high school students who participated in the MVP program in the 2018-2019 academic year. The current study examined proximal variables related to bystander intervention (bystander intentions, self-efficacy [SE] to intervene, responsibility to intervene [RI]). I examined the potential differential impact of the MVP program across three types of violence: sexual assault, adolescent dating violence, and bullying. Across both studies, there were few changes in study variables. When changes were observed for bystander intentions, it was a significant increase the proportion of students endorsing direct intervention strategies. Although there were few changes in SE scores, and small changes in RI scores, the increased scores demonstrated benefits of the MVP program. Consistent gender differences emerged, with girls reporting higher SE and RI compared to boys. Moreover, there were differences across schools, indicating school-level variables (e.g., school climate) are important to consider. Overall, the current study showed little variation in behavioral strategies, SE, and RI across types of violence, suggesting programs like MVP can be implemented to target multiple types of interpersonal violence among youth. Results haveimplications for the MVP program and for future research. Findings from the current study suggest shifting intentions and self-efficacy may require additional methods of intervention. The use of direct, skills-based exercises may increase the impact of the MPV program. Further, finding high rates of intention to use direct interventions compared to indirect bystander interventions highlight the need for discussion of the advantages and disadvantages of each type of strategy. Finally, continued research is needed to help understand what practice can improve confidence and what improves responsibility to intervene among high schoolers, especially boys.