Abstract
The developmental periods of adolescence (13- to 18-years), and emerging-adulthood (18- to 25-years) are important stages for an individual’s emotional and psychological development. For most, adolescence and emerging-adulthood are times of excitement, a time in which they mature and develop a deeper sense of personal identity. However, there is also a subset of the general population who can develop psychological problems such as substance abuse disorders, delinquency, depression, and suicide during this time. While the aetiology of these problems is not entirely clear, a number of researchers have shown that one of the biggest external predictors of problem-behaviour during adolescence and emerging-adulthood is peer influence.
Ostracism - the act of being excluded or ignored by others is one aspect of peer influence that warrants considerable scientific attention. A large body of research has shown that ostracism is associated with a decrease in an individual’s psychological well-being, including their self-esteem. Furthermore, work conducted both within our own laboratory and in others has suggested that adolescents and emerging adults may be at an increased risk of experiencing negative effects following ostracism.
The overall aim of this thesis was to investigate the psychological and behavioural impacts of ostracism in adolescent and emerging-adult samples. In Experiment 1, we recruited samples of adolescents, emerging-adults, and young-adults, and examined whether ostracism would influence participants propensity to assert control over a group situation by nominating themselves as a leader. For Experiment 2 and Experiment 3, we chose to focus our investigations on the emerging-adult population. In Experiment 2 we examined the relation between ostracism and risk-taking behaviour, and in Experiment 3 we examined the relation between ostracism and aggressive behaviour, and the effect of being ostracised by a group of close friends compared to a group of strangers.
Overall we found a number of interesting findings. First, consistent with the ostracism literature, in all three of our experiments we found that ostracism had a strong negative effect on participants’ psychological well-being. Second, we found a number of specific effects of ostracism on participants’ behaviour. In Experiment 1 we found that individuals who reported the greatest negative effect of ostracism on their self-esteem were more likely to nominate themselves for a leadership role; this may be one way in which individuals who are worst affected by ostracism attempt to buffer and re-build their diminished self-esteem. In Experiment 2 we found that ostracised participants were significantly less likely to take risks on a computer-based risk-taking task compared to included participants, therefore suggesting a link between ostracism and introverted behaviour. Finally, in Experiment 3 we found two findings; first, despite prior research suggesting a link between ostracism and increased aggressive behaviour, we found no effect of ostracism on aggression in our sample. Second, counter to the current theoretical models of ostracism, the magnitude of the negative effect of ostracism did not differ as a function of the source of ostracism. That is, individuals who were ostracised by complete strangers or by close friends both reported equal levels of psychological hurt. Overall this thesis provides new insight into the psychological and behavioural symptoms associated with the experience of ostracism.