ESC YOUNG CRIMINOLOGY AWARD RECIPIENT

More than 30% of young people globally have been victims of school-based aggression, according to a recent UNESCO report. Aggression is an international public health problem that has significant psychological, academic, and social consequences for young people. These consequences include depression and self-harm, with long-term impacts extending beyond the school gates and into adulthood. Whilst peers play a major role in driving aggression, the long-term success of peer- focused interventions is often limited.

Responding to this problem, my research focuses on situational (‘in-the-moment’) peer influences on aggressive behaviour. My debut article, which won the ESC Young Criminologist Award in 2024, presented a new theoretical model of peer influence and developed innovative methods to test this model. Here, I discuss the background, contributions, and practical implications of this work.

This project was inspired by three major challenges in peer influence research. The first challenge was the need to identify possible causal mechanisms underpinning peer effects. At the time, there was surprisingly little criminological research on how and why peers influence the decision-making processes that lead to aggressive behaviour. The second problem was the neglect of person-environment interactions and limited understanding of the individual characteristics that reduce susceptibility to harmful peer effects. The final challenge was the lack of suitable methods and data capable of testing the situational dynamics of peer influence in real- world contexts. Addressing these challenges was critical, not only for advancing the field but for informing the development of effective intervention strategies.

The first contribution of my research was theoretical. It applied Situational Action Theory (SAT; Wikström, Oberwittler et al., 2012) to the problem of school- based aggression, theorising the mechanisms and conditions of situational peer influence (see further Kennedy, 2024). By integrating interdisciplinary research, it specified how aggressive peers influence decision-making processes and identified the individual characteristics that moderate these effects. This work package contributed to the theoretical development of SAT and provided clear and testable implications for the situational model of peer influence.

Testing this theoretical model was challenging. It required situational data and methods that did not previously exist, even in prior empirical tests of SAT. This led to the adaptation of the PADS+ Space-Time Budget (STB) method to collect unique situational data on the types of peers present in real-world settings when aggression did (or did not) occur. The adapted STB interview recorded detailed time diary data covering multiple school days and combined this with a peer nomination technique to capture the peer context. This methodological contribution responded to repeated calls to improve the study of peer influences on aggressive behaviour, and it can be used to support future research across multiple fields.

The findings were compelling. Multi-method analyses showed that the impact of aggressive peers was greatest for ‘high propensity’ adolescents who had weak morality and a poor ability to exercise self- control. Whilst these adolescents were situationally vulnerable to the influence of aggressive peers, ‘low propensity’ adolescents who had strong morality and a well-developed ability to exercise self-control were situationally resistant. The latter group was rarely aggressive regardless of the peer context, which is something I argue interventions should aim to replicate. These findings fully supported the situational model of peer influence and this study was the first to use STB data to demonstrate this interaction at the situational level (see further Hardie, 2020).

With concerns about school-based aggression rising, the spotlight has shifted away from individuals and towards the influence of the broader peer group. Yet this research shows we cannot fully understand the influence of peers without recognising how their effects vary between young people. Crucially, strengthening morality and self-control may be more effective for preventing school-based aggression than limiting interactions with aggressive peers. This is good news. Whilst limiting these interactions is often unrealistic, we can protect young people from harmful influences by strengthening their resistance. This approach kills two birds with one stone, as it also reduces the prevalence of aggressive youth in the community.

So, what does this mean for policy and practice? I argue that changing the peer context is worthwhile, but these efforts must be supported by attempts to strengthen young people’s morality and ability to exercise self- control. This can be achieved through moral education and cognitive nurturing, which are long-term processes in which schools, families, and communities play important roles. Peers matter, but so does propensity, and it is the latter we should prioritise.

Looking ahead, there are some broad theoretical and methodological implications for future research. First, future research on peer influence and school-based aggression must account for individual differences
that moderate peer effects. Second, empirical tests of situational models should prioritise the collection and analysis of real-world situational data. By rethinking how we conceptualise and study peer influence, we can achieve our ambition of making schools safer places for young people.

References

Hardie, B. (2020). Studying situational interaction: Explaining behaviour by analysing person-environment convergence. Springer Nature.

Kennedy, L. (2024). Prioritise Propensity: A multimethod analysis of peer influence and school-based aggression. Deviant Behavior, 45(2), 139-168.

Kennedy, L. (2024). Explaining youth aggression: A situational model of peer influence. European Journal of Criminology, 14773708241272526.

Wikström, P. O. H., Oberwittler, D., Treiber, K., & Hardie, B. (2012). Breaking rules: The social and situational dynamics of young people’s urban crime. OUP Oxford.