Attentional modulation of the cardiac defense response in humans

How cardiac components of the defense reaction are modulated by attentional factors related to sensory intake versus sensory rejection was examined. Forty-eight men participated in a test of the heart rate response to three presentations of an intense auditory stimulus while performing one of three attentional tasks during the 80 s following stimulus onset: (a) internal (rejection) task, (b) external (intake) task, and (c) no task. Results showed a potentiation of the defense response only under the external attention condition. We concluded that defensive reactions, far from provoking the rejection of the aversive stimulus, require allocation of attention to processing that stimulus in detail.