Impulsiveness and arousal: Heart rate under conditions of rest and challenge in healthy males

Personality theory has proposed that the impulsive individual may be characterized physiologically by resting under-arousal along with greater increases in arousal when stimulated. Previously physiological measurement of impulsivity has primarily been conducted using electrocortical techniques in pathological samples. However, the current study tests the theory relating impulsivity and arousal using heart rate measures in healthy men scoring either high (n=14) or normal (n=14) on the Barratt Impulsiveness Scale. Heart rate was measured under two conditions; (1) rest, and (2) challenge (Paced Auditory Serial Attention Task, a cognitively demanding procedure of moderate duration and increasing intensity). High impulsive subjects exhibited generally slower heart rate under conditions of rest along with greater relative reactivity under a challenge condition (although this effect was reversible under continued increasing stimulation). These results are consistent with under-arousal theory of impulsivity and support the continued use of heart rate measures for addressing impulsivity theory.