Callous–Unemotional Traits and Their Association with Neurodevelopmental Disorders: Insights from Gaze Behaviour During Emotion Recognition

Callous-unemotional (CU) traits are characterised by reduced empathy, guilt, and emotional responsiveness, and are strongly linked to atypical socioemotional processing. Eye-tracking research provides a valuable window into these processes by capturing early developing patterns of attention to emotionally salient social cues, particularly facial expressions. This narrative review examines how alterations in gaze behaviour contribute to the emergence of CU traits across neurodevelopmental disorders (NDs), with a focus on autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD), and conduct disorder (CD). Across studies, elevated CU traits are associated with reduced fixations on the eye region, most consistently in response to fearful faces. ASD is associated with robust eye avoidance, ADHD with inhibitory and attentional control difficulties during face processing, and CD with atypical gaze allocation to negative emotional expressions such as fear and anger. These patterns appear amplified when CU traits co-occur with NDs. Competing explanatory accounts, including aberrant amygdala functioning, oculomotor disinhibition, and hostile attribution biases, each capture aspects of these patterns but fail to provide a unified explanation. Integrating developmental, neurobiological, and environmental perspectives, we propose that CU traits reflect a transdiagnostic developmental construct shaped by early attentional-emotional mechanisms, rather than a disorder-specific identity.