Previous studies have shown that youth with callous-unemotional traits are at increased risk for both aggression and antisocial behavior. A recent study featuring PISC Senior Scholar Rebecca Waller, PhD, evaluated the relationship between callous-unemotional traits and autonomic activity. 162 clinically referred youth were evaluated during three social interactions. The interactions were designed to provoke negative emotions with their caregivers. Autonomic activity was assessed through respiratory sinus arrhythmia. Results indicate that, overall, all youth exhibit decreased respiratory sinus arrhythmia during the encounter. Despite this, youth with elevated callous-unemotional traits have a distinct respiratory sinus arrhythmia compared to their counterparts. The team concludes that a decrease in respiratory sinus arrhythmia during social interactions is a signal of callous-unemotional traits.