Cardiac Response During Auditory Selective Attention to Tones and Affective Sounds

We conducted an experiment to determine if attention to affective sounds showed a lateral bias. Twenty-two participants were instructed to respond to one of two pure tones presented monaurally and to a set of pleasant and unpleasant sounds from the International Affective Digitized Sounds set. Participants were instructed to respond to pleasant or unpleasant sounds in the right or left ear, attending to pleasant/right, pleasant/left, unpleasant/right, and unpleasant/left sounds in separate blocks. Evoked cardiac response to the tones showed significant cardiac deceleration in response to attended sounds in the attended ear. In addition, pleasant sounds elicited significant cardiac deceleration when attended in the right ear, but not in the left. Unpleasant sounds elicited significant cardiac deceleration when attended in both ears. Consistent with the anterior valence hypothesis, our data suggests that pleasant sounds are mainly processed in the left hemisphere, but in contrast to this hypothesis, unpleasant sounds are processed bilaterally.