A new study by Pacheco-Unguetti and Parmentier just accepted for publication in the British Journal of Psychology shows that participants in a state of happiness are more distracted by unexpected sounds while performing a visual task.
The study extends Pacheco-Unguetti and Parmentier's (2014) work reporting similar findings in participants in a state of sadness. Together, the two studies suggest that enhanced emotional state, negative or positive, increase the risk of distraction by unexpected stimuli. The hypothesis privileged by the authors is that enhanced emotional states consume mental resources that would otherwise be recruited to help reorient attention away from attention-grabbing distractors.
Pacheco-Unguetti, A. P., & Parmentier, F. B. R. (in press). Happiness increases distraction by auditory deviant stimuli. British Journal of Psychology.
Abstract: Rare and unexpected changes (deviants) in an otherwise repeated stream of task-irrelevant auditory distractors (standards) capture attention and impair behavioral performance in an ongoing visual task. Recent evidence indicates that this effect is increased by sadness in a task involving neutral stimuli. We tested the hypothesis that such effect may not be limited to negative emotions but reflect a general depletion of attentional resources by examining whether a positive emotion (happiness) would increase deviance distraction too. Prior to performing an auditory-visual oddball task, happiness or a neutral mood was induced in participants by means of the exposure to music and the recollection of an autobiographical event. Results from the oddball task showed significantly larger deviance distraction following the induction of happiness. Interestingly, the small amount of distraction typically observed on the standard trial following a deviant trial (post-deviance distraction) was not increased by happiness. We speculate that happiness might interfere with the disengagement of attention from the deviant sound back toward the target stimulus (through the depletion of cognitive resources and/or mind wandering) but help subsequent cognitive control to recover from distraction.