The informational constraints of behavioral distraction by unexpected sounds: the role of event information.

Sounds deviating from an otherwise repeated stream of task-irrelevant auditory stimuli (deviant sounds among standard sounds) are known to capture attention and impact negatively on ongoing behavioral performance (behavioral oddball distraction). Traditional views consider such distraction as the ineluctable consequence of the deviant sounds' low probability of occurrence relative to that of the standard. Contrary to this contention, recent evidence demonstrates that distraction by deviant sounds is not obligatory and occurs only when sounds (standards and deviants), though to be ignored, act as useful warning cues by providing information as to whether and when a target stimulus is to be presented (Parmentier, Elsley, & Ljungberg, 2010). The present study aimed to extend this finding by disentangling the roles of event information (target's probability of occurrence) and temporal information (target's time of occurrence). Comparing performance in a cross-modal oddball task where standard and deviant sounds provided temporal information, event information, both, or none, we found that distraction by deviant sounds emerged when sounds conveyed event information. These results suggest that unexpected changes in a stream of sounds yield behavioral distraction to the extent that standards and deviants carry relevant goal-directed information, specifically, the likelihood of occurrence of an upcoming target.