Dual Task Assessment of Age Differences in Mental Workload with Implications for Driving

Abstract

Older drivers constitute the fastest growing segment of the driving population, in terms of both number of drivers and number of miles driven. Accident analyses reveal that older drivers are not able to fully compensate for emerging reductions in perceptual/cognitive capacity. Establishment of a method of assessing older drivers with perceptual/cognitive impairments which place them at risk of accidents is imperative. In this investigation, a subsidiary task of mental arithmetic was demonstrated to be sensitive to age differences in relative mental workload resulting from increased steering task complexity in a simulated driving task. As steering task difficulty increased, verbal response latency to concurrent mental arithmetic problems increased for older, but not younger, participants. Steering error remained stable across single and dual task conditions indicating that the secondary mental arithmetic task did not interfere with steering (primary task) performance. These results provide preliminary support for the use of this assessment technique outside of the laboratory in actual driving situations.