BackgroundThe development of morality is vital for fostering prosocial behavior and enhancing both individual and societal well-being. Clarifying what contextual and individual factors play a role in moral processes during childhood can contribute to our understanding of the development of morality. Given the previous acknowledgment of importance, yet lack of existing empirical findings, the study focused on the significance of callous-unemotional traits (i.e., an affective-interpersonal personality trait, related to psychopathy in adulthood) and emotion regulation (i.e., an essential part of socio-emotional competence, and a transdiagnostic factor in the development of psychopathology) for moral emotions and cognitions during middle childhood. The concrete aim was to examine direct and indirect effects of callous-unemotional trait dimensions (callousness, uncaring, unemotionality) onto immoral emotional attribution (i.e., feeling good after immoral decisions) and admissibility of immoral actions (i.e., evaluating immoral actions as being okay) via emotion regulation skills.MethodsA cross-sectional study was conducted with 194 children attending Grades 1 to 4, and their primary caregivers. The children completed the Inventory of Callous-Unemotional Traits and caregivers completed the Emotion Regulation Checklist. The children were also presented with a set of moral dilemma vignettes, and asked about the emotions of protagonists who acted immoral, and the admissibility of their actions.ResultsPath-model analysis revealed (1) negative direct effects of emotion regulation skills onto immoral emotional attribution and admissibility of immoral actions, (2) positive direct effects of the dimensions callousness and uncaring onto immoral emotional attribution and admissibility of immoral actions, and (3) negative direct effects of dimensions callousness and uncaring onto emotion regulation skills. Indirect effects, indicating that emotion regulation skills mediate the association between the callous-unemotional trait dimensions and morality, were also found.ConclusionThe findings address a knowledge gap and indicate that emotion regulation skills, callousness, and uncaring play an important role in morality in middle childhood and should be included in frameworks of moral decision-making and development.