Electrophysiological indexes of the detection and processing of auditory distractors

Resumo

The occurrence of auditory changes in a stable environment may cause distraction. The pattern of this effect in the present thesis depended on the salience of the feature undergoing auditory change, the temporal distance and the spatial location between the task-irrelevant and task-relevant information. Moreover, the electrophysiological recordings helped to elucidate the cognitive processing underlying behavioural distraction. First, an early and automatic call for attention triggered by mismatch negativity (MMN) was generated by various types of changes, which corroborated its role as a genuine change detector. Second, the effective orienting of attention to the unexpected changes indexed by P3a appeared sensitive to the spatial location of the distractors, suggesting that the orienting of attention could be indeed an attentional spatial switch. And third, the cognitive processing of returning to primary task performance after a momentary distraction associated with the reorienting negativity (RON) component depended on the impaired stage of the ongoing target processing. Taken together, the results shed new light on the mental chronometry of auditory distraction.