Auditory distraction during visuomotor steering

Abstract

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.