Effects of a Controlled Auditory–Verbal Distraction Task on Older Driver Vehicle Control

Abstract

Engaging in conversation diverts attention from cognitive processes associated with driving. Drivers tend to commit errors that may lead to crashes when their attention is focused away from the driving task. The interference occurs at the level of central attentional processes that are especially susceptible to aging. The current study assessed the effects of a controlled auditory—verbal processing load induced by the Paced Auditory Serial Addition Task (PASAT) on vehicle control by 160 legally licensed older drivers. Of these drivers, 78 were neurologically normal (mean age of 71 years) and 82 (mean age of 75 years) had impairments of selective attention but no diagnosable neurological disease. Measurements aboard the instrumented vehicle Automobile for Research in Ergonomics and Safety showed that performing the PASAT reduced speed and steering control of the older drivers relative to baseline (no-task) driving conditions and was associated with greater counts of at-fault safety errors. Yet, driving performance did not differ significantly between neurologically normal and attention-impaired older drivers between PASAT and no-PASAT (baseline) conditions. It may be that the PASAT, which involves auditory-verbal and working-memory, sustained-attention, and executive-function components, commands different resources than driving on uneventful highways, which might rely on overlearned, automatic cognitive processes. Interference produced by PASAT, like that of cell phone operation, might become more evident during demanding driving conditions, as exist at busy traffic intersections. Relevant studies in these potentially unsafe circumstances can be conducted in a driving simulator, as in our ongoing research on older drivers.