One function of working memory is to protect current mental processes against interference. In contrast, to be able to react flexibly on unpredictable environmental changes working memory should not totally be encapsulated from processing task unrelated information; that is, it should remain distractible. By manipulating the task load of the primary task in an auditory distraction paradigm we investigated how these opposing functions are coordinated by working memory. The behavioural results show that distraction effects were still present but reduced markedly with higher task demands. This suggests that working memory exerts some control over involuntary attention. In addition, event-related brain potentials related to the different processing stages reveal that the preattentive change detection system underlying distraction was not modulated by task demand whereas distraction per se was. The present data suggest that working memory is able to coordinate the maintenance of distractibility and the focus on the task at hand.

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Attentional reallocation after a distracting event is an important function of cognitive control. This process is tapped by the reorienting negativity (RON) event-related brain potential. It was argued that the RON reflects orientation of attention to relevant information in working memory. To test this hypothesis participants performed an auditory duration discrimination task. The stimuli were presented in a frequent standard or a rare deviant pitch with deviants resulting in behavioral distraction. Participants accomplished this task under two conditions: In the refocus condition participants were asked to respond to every stimulus; in the reorient condition participants were instructed to ignore deviant stimuli and omit a reaction. The results suggest that different functions of attentional allocation are reflected by two RON subcomponents: the fast orientation of the focus of attention in working memory and a subsequent poststimulus evaluation process.

The present study investigates bottom-up effects serving the optimal balance between focusing attention on relevant information and distractibility by potentially significant events outside the focus of attention. We tested whether distraction, indicated by behavioral and event-related brain potential (ERP) measures, varies with the strength of task-irrelevant deviances. Twenty subjects performed a tone-duration discrimination task (200 or 400 ms sinusoidal tones presented equiprobably). The stimuli were presented with frequent standard (p = 0.84; 1000 Hz) or infrequent deviant (p = 0.16) pitch. These task-irrelevant pitch changes consisted in a frequency increase/decrease of 1%, 3%, 5%, or 10%. Each of them resulted in prolonged reaction times (RT) in the duration discrimination task and elicited the MMN, P3a, and RON components of the ERP. Importantly, these measures did increase as a function of pitch deviance. Separating the individual trials on the 1% deviation level into trials with and without RT prolongation, i.e., behavioral distraction effect, revealed that both subgroups had similar MMN, but P3a and RON were confined to the trials with RT prolongation. Results are interpreted within a model relating preattentive deviance detection, distraction, and working memory.

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This study aimed at differentiating between memory- and task-related processes and their correlates on the electrodermal and electrocortical level during information concealment. Variations of the Guilty Knowledge Test were implemented in two experiments while we measured skin conductance responses (SCRs) and event-related brain potentials. P300 amplitudes were specifically enhanced for items requiring a deviant behavioral response but they were not sensitive to concealed knowledge. In contrast, N200 amplitudes differed between memorized and irrelevant items in both experiments. SCR measures reflected a combined influence of task relevance and probe recognition, and they provided incremental validity above N200 amplitudes. These results suggest that the P300 mainly reflects task relevance in the given experimental setting whereas the N200 amplitude is sensitive to previously encoded information and potentially linked to response monitoring processes.

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