Physiological reactivity in children with high callous-unemotional and autistic traits: investigating unique and interactive effects

Empathy deficits are a hallmark sign of both callous-unemotional (CU) and autistic traits. Despite these similarities, prior work did not investigate how these traits relate to physiological reactivity (heart rate and skin conductance) in response to emotional or empathy-eliciting stimuli. Understanding the physiological mechanisms associated with emotional processing deficits among individuals with autistic or CU traits is a critical step for improving both assessment and interventions. The current study was designed to investigate the unique and interactive contributions of CU and autistic traits in predicting physiological reactivity. Heart rate (HR) and skin conductance (SC) activity in response to sad, fearful and happy emotional videos were collected form young children. Participants for the current study (n = 163;M-age = 7.30, SD= 1.42; 44.2% girls) were recruited from a larger community sample of 1652 children and were selected based on their levels of empathy. Regression analysis revealed that boys, but not girls, with high levels of CU traits exhibited low SC reactivity during sad and fearful stimuli. No significant associations were revealed for autistic traits. Finally, an interesting interaction effect suggested that CU traits were associated with stronger HR reactivity to fear stimuli only when autistic traits were low. The identified differences in physiological reactivity can inform etiological hypothesis by providing evidence for the underlying physiological mechanisms related to emotional processing among children high in CU traits but not in autistic traits.