In a rare surge of violence, Australian cities have been affected recently by multiple knife attacks. The most devastating occurred on 13 April at a shopping centre at Bondi Junction in Sydney. A lone assailant’s rampage left six dead, including himself, and many others injured. Just two days later, another horrific episode unfolded at Christ The Good Shepherd Church in Wakeley, escalating fears as it was declared a terror attack. Since these incidents, reports of knife-related violence seem to have spiked in Australian media. Is this merely coincidental, or are we witnessing a pattern similar to those observed in other parts of the world following mass violent attacks?
While knife attacks are not as extensively studied as other violent crimes like gun violence and mass shootings, or other forms of terrorism, the lessons that emerge from them can be universally poignant and instructive, regardless of the method of violence.
Contagion effects
The potential for mass violence to spawn copycat or contagion effects is a significant concern among researchers who study these events. In this context, contagion refers to a phenomenon where individuals or groups prone to violence replicate methods of political or ideological violence that have gained attention through mass media. Supporting this, research on suicide terrorism has demonstrated that such acts of violence tend to spread through non-random patterns, exhibiting waves, clusters, and frequencies that suggest a contagion effect. Specifically, this refers to the erratic pattern of a few closely spaced violent events occurring after a relative period of inactivity.
Concepts such as clusters, waves, and copycats are often discussed in relation to mimetic and social contagion theories. The influence of mass media in fostering contagion and mimetic behaviour can be considerable, but it involves an interplay of various inspirations — including social media, blogs, chatrooms, the broader social milieu, and the geopolitical conflicts of the time — before an individual replicates an act like terrorism.
Research on mass shootings indicates that social contagion can indeed lead to copycat mass crimes, where the occurrence of one mass shooting, for example, significantly increases the likelihood of subsequent shootings in the near future. This pattern suggests that each incident potentially serves as a trigger for another, propagating a cycle of violence through imitation and media exposure. More specifically, after a mass shooting another is more likely to occur within an average of 13 days. Copycat mass shooters often replicate high-profile incidents that result in a significant number of fatalities, usually more than four.
School shootings in the United States often reflect the perpetrator’s desire for media attention and notoriety. Research indicates that, due to the intense regional and national media coverage they receive, there is a high likelihood of subsequent copycat attacks. An investigation into the US state-level school shooting data from 1990 to 2017 revealed that the risk of additional school shootings in the same or neighbouring states increases following a prominent attack.
A heavily investigated example and case study is the Columbine massacre, which has been shown to have served as a “model” for perpetrators in 30 US states across 74 sophisticated plots. These individuals attempted to replicate the Columbine attack, often aiming to cause even greater fatalities.
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Another telling example is what researchers have called “the Christchurch cluster”. On 15 March 2019, Brenton Tarrant shot and killed 51 people and wounded another 40 at two mosques in Christchurch, New Zealand. Before his attack, Tarrant published a manifesto in which he justified his actions, citing Anders Breivik, perpetrator of the 2011 attacks in Norway, as his “true inspiration”. The Christchurch attack would directly inspire several other attacks in 2019 that followed the same cultural script — including the Poway synagogue shooting in California, the Walmart shooting in El Paso, Texas, the Al-Noor mosque shooting in Norway, and the Halle synagogue shooting in Germany. Those attacks were all shootings in which the perpetrator, explicitly inspired by Tarrant’s actions, aimed to inflict mass casualties against a specific ethnic or religious group using one or more firearms. This copycat or inspiration effect is anything but new; indeed, it has been demonstrated in approximately one-third of all lone-actor terrorism cases.
Analyses of vehicle-ramming attacks between 2015 and 2017 have also highlighted how the publicity surrounding such acts can influence and potentially increase the likelihood of similar incidents. This suggests that the very act of violence, when widely reported and discussed, may serve as a model for imitation by others predisposed to such behaviours.
Social contagion theory has been employed to understand how media could contribute to the spread of violence, and even suicide. Celebrity suicides, for example, have been shown to be followed by a sudden spike of suicides among the general population. This is why the mass media in the United States agreed to cease reporting names and some details of suicides since 1994.
The social contagion of violence
These theoretical principles are equally applicable to terrorism. The social contagion of terrorism represents a complex and contentious issue. While a consensus has yet to be established, there is substantial support for the role of mimetic theory in the proliferation of violent behaviours. This suggests that acts of violence may be replicated in a manner similar to other forms of violence, influenced by media portrayal and public attention.
Much like the way pathogens spread in germ theory, violent tendencies can transmit from one individual or community to another through close social contact (including online communities), unless there are preventative measures in place. This form of social contagion requires “immunities” to effectively resist the spread. Examples of such immunities include access to quality education, increased political participation, reduced experiences and perceptions of unfairness and injustice, higher socio-economic status, and enhanced access to both resources and economic and political power.
The World Health Organisation recognises the portrayal of violence in the media as a significant public health threat. As such, they have developed recommendations for responsible reporting — particularly concerning suicide and homicide. These guidelines aim to mitigate the potential harmful effects of such media coverage, acknowledging the powerful role it plays in shaping public perceptions and behaviours.
The influence of mass media on violent behaviour, particularly in the context of terrorism and mass killings, can be conceptualised through the lens of “imitation” and ripple effects. Most individuals who commit these acts do not replicate personally witnessed events — rather, they imitate behaviours and scenarios presented through various media channels. These sources, including traditional mass media, play a pivotal role by providing detailed coverage that may include the attacker’s identity, motives, and background. Such extensive and often sensationalised reporting can grant notoriety to perpetrators, potentially encouraging imitation by those who seek similar recognition. For example, after scrutinising the media coverage of the 1996 Atlanta Olympics bombing, “London Nail Bomber” David Copeland realised that mass violence would help him “be famous” and “to get on the news as the top story”.
While mass shootings represent a small fraction of total gun deaths in the United States, the sensationalised coverage tends to overlook the more frequent instances of other forms of gun violence — like suicides and domestic violence.
Moreover, sensationalised reporting can also perpetuate negative stereotypes about mental illness, increasing public stigma and misunderstanding. Biased media coverage of mental illness can increase negative attitudes toward those with mental health conditions, leading to greater social avoidance. For instance, in Germany, public distance from individuals with schizophrenia measurably widened following extensive media coverage of two mass shootings. Similarly, a national survey in the United States found that over half of Americans view people with mental illness as more dangerous than those without, despite the fact that individuals with mental health issues are more likely to be victims rather than perpetrators of violence.
The reducing the negative consequences of media reporting
The most effective approach to mitigating the negative effects of media reporting on terrorism and mass violence would be for media organisations to adopt responsible reporting guidelines developed by experts in terrorism and journalism. These guidelines should include training for editors and journalists to understand the potential effects their reporting can have.
To combat the media contagion effect associated with mass violence, several organisations have, in fact, collaborated to produce guidelines for the media. These guidelines emphasise responsible reporting to minimise the likelihood of inspiring copycat incidents. Key aspects include:
- avoiding glorification of the perpetrator;
- not showing photos of victims alongside perpetrators;
- and reducing the sensationalism of the events.
The guidelines also promote “helpful reporting”, which involves educating the public on recognising and responding to concerning behaviours. Recommendations aim to enhance public knowledge without stigmatising mental illness or inadvertently glorifying violent acts, focusing instead on community resilience and sensitive coverage of survivors and their families.
It’s also important to note that, while these guidelines address traditional media, the contagion effect often extends into less regulated spaces like social media and extremist forums, which are beyond these guidelines’ reach. The persistent issue in less regulated spaces like social media and extremist forums highlights the urgent need for social media and tech companies to assume greater accountability.
Initiatives like Australia’s establishment of the eSafety Commissioner and the Global Internet Forum to Counter Terrorism are promising steps towards addressing these challenges.
Milad Haghani is a Senior Lecturer at the University of New South Wales, specialising in disaster risk and public safety.
Ramón Spaaij is Professor of Sociology at Victoria University, specialising in violence, social inclusion, and social change.