Design and Validation of a Moral Anger Scale for Online and Offline Peer Aggression in the School Context

Moral emotions play a crucial role in aggressive group dynamics. Developing specific instruments to measure these emotions is essential for understanding the decision-making processes. In particular, moral anger refers to the anger elicited by perceived injustice or transgressions of ethical values. This emotion is especially relevant in the school context, where research suggests an association between the anger experienced in reaction to aggression and their ethical behavior. However, to date, no specific instrument has been developed to measure moral anger in response to such situations. This study aimed to design and validate a scale for measuring moral anger in the context of online and offline peer aggression and to examine the predictive validity of the instrument in relation to defending behaviors. A total of 3,183 pupils (51.6% boys, <i>M</i>_age = 12.76, <i>SD</i> = 1.52) participated in the study. The results confirmed that the unidimensional model provided the best fit, presenting good psychometric properties in terms of reliability and validity. Likewise, the invariance and replicability of the scale were tested across gender and age groups. Good incremental predictive validity was also demonstrated, as evidenced by a positive association between moral anger and defending behaviors. In conclusion, the instrument designed in this study can be used to measure moral anger in aggressive peer contexts, both online and offline. Identifying moral anger is a key to understanding group dynamics in cases of aggression and power imbalance, as well as the behavior of bystanders. Moreover, this research contributes to the development of interventions aimed at promoting social justice, equity, and the creation of a more peaceful society that actively opposes mistreatment and aggression.