Date of Award


Degree Type


Degree Name

Doctor of Philosophy


School of Arts and Humanities

First Advisor

Professor Alfred Allan

Second Advisor

Professor Donna Cross


With the modern proliferation of computers, the Internet and smart phones, adolescents are at increased risk of cyber-aggression: negative, harmful behaviour expressed through electronic means and aimed at an individual (or group of individuals). Cyber-aggression can have serious consequences for the social, emotional and physical health of both targets and perpetrators. Some experts recommend tackling cyberaggression using the strategies applied to face-to-face forms of aggression and bullying in school environments. One such strategy is to encourage peer bystanders to intervene in a positive way, which has been demonstrated to influence both the duration and severity of bullying episodes in the school environment. However, cyber-aggression has some unique characteristics that differentiate it from school-based aggression such as bullying, including the potential for perpetrator and bystander anonymity, the rapid dissemination of material, and the permanence of information placed on the Internet. It therefore remains uncertain whether these unique characteristics make the wholesale adoption of face-to-face schoolbased bystander interventions inappropriate for the online environment. This thesis sought to clarify the key influences on young adolescent bystanders’ behaviour in the online environment to determine the extent to which it differs to that in the school environment.

An exploratory mixed methods design was undertaken involving three phases. Phase One adopted a qualitative, phenomenological approach using in-depth interviews with 24 adolescents in Grades 8–10, to explore their perception of young bystanders’ attitudes and likely behaviours when witnessing cyber-aggression. In-depth vignette-based interviews were undertaken to explore two key research questions: (a) What factors do young adolescents think influence bystanders’ decisions to intervene when witnessing cyber-aggression? and (b) What do young adolescents perceive as differences in bystanders’ responses to peer aggression in the online versus offline (school) environments? A thematic analysis identified key themes arising from Phase One. Firstly, bystander behaviours in the online environment are perceived to be influenced by the relationship of the bystander to the perpetrator and target, with bystanders more likely to take action when they have a close relationship with one of these individuals. Relationships also assisted online bystanders to understand the context of the situation, the perceived severity of the incident and therefore the need, or otherwise, to seek adult assistance. An important difference between online and school environments is that the online environment was perceived to be lacking in clearly established rules, authority figures and formal reporting mechanisms when witnessing aggressive behaviour. In addition, when witnessing online transgressions young adolescent bystanders are more hesitant and likely to ignore or avoid intervening. This is due, in part, to difficulties they experience trying to ascertain perpetrator intentions in the absence of non-verbal cues.

Phase Two sought to quantitatively confirm the themes arising from Phase One and involved the development of a quantitative measure and use of vignettes to manipulate major themes with a larger sample of adolescents in Grades 9–10 (n=292). Statistical analysis confirmed that bystander helping behaviours were more likely when the target was a close friend and when perceived harm to the target was high. Bystanders also reported being less likely to approach teachers or publicly defend targets in the online environment compared to the school environment. In addition, female bystanders were more likely to intervene, regardless of the online or school environment.

Phase Three evolved from the results of the first two phases and involved a systematic review to explore the role of moral disengagement in bystander behaviours, highlighting future research directions and implications for online interventions. In this phase of the research, existing literature describing bystanders’ use of moral disengagement mechanisms when witnessing online and school bullying was appraised. A systematic review of empirical literature published over the last 25 years revealed a scarcity of research addressing bystanders’ use of moral disengagement in face-to-face environments, and no studies examining this issue in the online environment when witnessing bullying within the search parameters. In school environments, moral disengagement was found to be more likely in boys and increasing with age; affected by individuals’ histories, empathy, and selfefficacy; negatively associated with pro-social bystander behaviours; and highly influenced by socio-environmental factors, such as school culture.

Collectively the three phases suggest that programs designed to encourage positive online bystander behaviours can be similar to face-to-face approaches, but also need to compensate for some aspects unique to the online environment. Such programs should consider the impact of relationships on young people’s active defending behaviours, their inhibitions surrounding public displays of bystander behaviour of any kind, and the lack of adult presence in the online environment. Strategies should sensitise adolescents to the potential harm of cyber-aggression and assist them to counter the tendency to morally disengage in the online environment. This might be achieved through programs designed to develop pro-social skills in online bystanders, to enable young people to intervene as peer supporters when they become aware of cyber-aggression.

Access Note

Chapter 3 has been omitted from this version of the thesis by author’s request.