Dissertations, Theses, and Capstone Projects

Date of Degree


Document Type


Degree Name





Yu Gao

Committee Members

Jennifer E. Drake

Cong Liu

Jennifer B. Wagner

Wei Wang

Subject Categories

Biological Psychology | Experimental Analysis of Behavior | Other Neuroscience and Neurobiology | Social Psychology


social exclusion, aggression, psychopathy, psychophysiology


Humans have a fundamental need to form and maintain social connections, and thus experiencing social exclusion is extremely distressing as it threatens this basic human need. Individuals who are socially excluded often respond aggressively, not only towards their ostracizers but also towards innocent bystanders, with ostracism being implicated in extreme acts of violence such as school shootings. However, individual differences in behavior exist within the context of social exclusion as not everyone responds aggressively after being ostracized. Identifying risk factors for retaliatory aggressive behavior following experiences of social exclusion may facilitate the development of targeted interventions aimed at mitigating such behaviors. One potential correlate of aggression is the coordination of the body’s physiological response to a stressor, as prior research has identified that a dysregulated response by the autonomic nervous system to stressors may predispose individuals to maladaptive behaviors. Furthermore, psychopathic traits which are characterized by deficient emotional regulation processes have been linked to aberrant autonomic stress responses as well as to increased aggressive behaviors, and may potentially moderate people’s behavioral and autonomic responses. Thus, the goals of the current study were to examine the autonomic stress response to an experience of social exclusion, and to identify whether individual differences in this stress response are implicated in subsequent retaliatory aggressive behavior. Additionally, the study aimed to investigate the effects of psychopathic traits on the physiological and aggressive reactions to social exclusion. In the study, 159 participants (61.6% female, mean age = 22.20 years) recruited from a college campus were randomized to either be included or excluded in an online social game while the activity of their autonomic nervous system was recorded. Following the game, participants completed a task during which they were able to aggress against an individual that has either included or excluded them in the prior game. Results showed that excluded participants experienced heightened activity of their sympathetic nervous system compared to included participants, supporting the hypothesis that social exclusion is a distressing experience that evokes physiological changes reminiscent of a stress response. Furthermore, an uncoordinated pattern of sympathetic and parasympathetic activity indicative of a dysregulated stress response predisposed excluded individuals to higher retaliatory aggression. Lastly, while psychopathic traits did not influence the autonomic stress response to the experience of exclusion, they were found to either predispose or protect individuals from aggressive behavior in the context of social exclusion, depending on the specific factors of psychopathy. The current study thus identified biological and personality factors that may influence how individuals respond to the distressing experience of social exclusion and highlighted the importance of adopting a multi-system approach in understanding the correlates of aggression. Uncovering the etiological basis for aggressive behavior following ostracism can inform targeted interventions for individuals at high risk for aggression.