Aggressive traits shape body and facial emotion recognition: exploring tVNS modulation in forensic contexts

Emotion recognition is fundamental in forensic contexts, as it supports social cognition, interpretation of others’ intentions, and regulation of adaptive social behaviour. Emotional signals may be conveyed through multiple channels; however, the interplay among these modalities remains poorly understood. Moreover, limited evidence is available regarding the role of vagal activity in modulating emotion recognition. The present study investigated the effects of transcutaneous vagus nerve stimulation (tVNS) on emotion recognition while also examining the contribution of individual differences in aggressivity. To date, 21 participants completed the Aggression Questionnaire and were categorized into low- (LAG), medium- (MAG), and high-aggression (HAG). Participants were tested under both active and sham tVNS conditions while performing multimodal emotion recognition tasks requiring the matching of emotional or neutral vocalizations with visual stimuli depicting either bodily or facial expressions. Preliminary results indicated tVNS did not significantly affect accuracy or reaction times across conditions. However, significant group differences emerged. Post hoc Tukey tests revealed that HAG were less accurate than LAG (p = .011) in recognizing emotions from body and face cues, with no other significant differences observed. These findings suggest that individual differences in aggressivity may shape emotion recognition abilities, independently of vagal modulation. Reduced accuracy in high-aggression individuals when processing emotional cues may have important implications for forensic rehabilitation, as impaired recognition of victims’ emotional states could contribute to the persistence of aggressive behaviour and increase the risk of reoffending. A priori power analysis indicates that a sample of 50 participants will be required to confirm these preliminary findings.