Distraction is a major causal factor of road crashes, and very young and older drivers seem to be particularly susceptible to distracting stimuli; however, the possibilities of exploring the causes for increased distractibility of these groups in real traffic seem to be limited. Experiments in a driving simulator are a good choice to eliminate the risk for crashes and to present highly standardized stimulus combinations. In the present study, 72 subjects from four age groups completed a driving task that required occasional responses to the brake lights of a car in front. In addition, in certain experimental conditions, subjects had to respond to distracting visual or auditory stimuli. In addition to behavioral data, electrophysiological correlates of stimulus processing were derived from the electroencephalogram (EEG). In the two older groups, braking response times increased even in a simple task condition when visual distraction stimuli occurred. In more complex task conditions braking response times increased with acoustic and visual distractors in the middle-aged group as well. In these complex task conditions braking error rates, especially the missing of braking reaction in favor of the distracting task, increased under visual distraction with increasing age. Associated with this, a reduced P3b component in the event-related potential indicated an unfavorable allocation of mental resources. The study demonstrates the potential of driving simulators for studying effects of distraction, but also their limitations with respect to the interpretability of the results.
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