Auditory distraction during visuomotor steering

Auditory distraction, the involuntary processing of unexpected sounds, allows us to become aware of changes in our environment that otherwise might go unnoticed. For example, while being focused on the road ahead, the sound of a car horn might warn us from an approaching car that we would have neglected, without auditory distraction. It is assumed that distraction occurs when an event violates our expectations about our auditory environment. For example, in auditory oddball tasks, sounds with a lower probability of occurrence are less expected and, thus, are reliably shown to be processed preferentially, reflected in increased measured brain potentials (i.e. eventrelated potentials (ERPs)), relative to expected sounds. However, besides the probability of occurrence, it was recently suggested that also the local short-term context in which an event occurs, as well as expectations that are based on our long-term memory content, influence our expectations and thus define auditory distraction. In the first part of the current dissertation, I provide evidence to support this assumption. Both, the physical difference of an unexpected event from its short-term context as well as its difference from long-term memory expectation were shown to result in increased processing of the eliciting event, as reflected in enhanced brain potentials. The increased processing of an unexpected auditory event also increases its demand for attentional resources and, thus, can decrease the performance in simultaneously performed tasks. It is, however, still under debate whether auditory distraction places a demand on general resources that are shared between sensory modalities or whether this demand is specific to the auditory modality. In the current dissertation, I argue that both is possible. Events that are distracting, due to their difference from their short-term context, increased the demand for general attentional resources that are shared between the auditory modality and a visually presented visuomotor control task. Events that are distracting because they differ from our long-term memory expectations increase the demand for modalityspecific attentional resources. But attentional resources are not only involuntarily attracted by unexpected auditory events. It is also possible to voluntarily attend to relevant events or tasks. While most research is devoted to study either voluntary or involuntary attentional processing, recent evidence suggested that both processes might interact. Indeed, in the second part of my dissertation, I show that increased demands, in a voluntarily performed visuomotor control task, can decrease the involuntary auditory distraction. More specifically, this is only the case for such demands which are known to increase the demand for ”perceptualcentral” resources. Furthermore, I show that a decrease of auditory distraction can not only result from high task demands, but also occurs in cases in which the auditory modality is perceived as being irrelevant

Steering Demands Diminish the Early-P3, Late-P3 and RON Components of the Event-Related Potential of Task-Irrelevant Environmental Sounds

The current study investigates the demands that steering places on mental resources. Instead of a conventional dual-task paradigm, participants of this study were only required to perform a steering task while task-irrelevant auditory distractor probes (environmental sounds and beep tones) were intermittently presented. The event-related potentials (ERPs), which were generated by these probes, were analyzed for their sensitivity to the steering task’s demands. The steering task required participants to counteract unpredictable roll disturbances and difficulty was manipulated either by adjusting the bandwidth of the roll disturbance or by varying the complexity of the control dynamics. A mass univariate analysis revealed that steering selectively diminishes the amplitudes of early P3, late P3, and the re-orientation negativity (RON) to task-irrelevant environmental sounds but not to beep tones. Our findings are in line with a three-stage distraction model, which interprets these ERPs to reflect the post-sensory detection of the task-irrelevant stimulus, engagement, and re-orientation back to the steering task. This interpretation is consistent with our manipulations for steering difficulty. More participants showed diminished amplitudes for these ERPs in the ‘hard’ steering condition relative to the ‘easy’ condition. To sum up, the current work identifies the spatiotemporal ERP components of task-irrelevant auditory probes that are sensitive to steering demands on mental resources. This provides a non-intrusive method for evaluating mental workload in novel steering environments