John K. Lenneman

Cardiac measures of driver workload during simulated driving with and without visual occlusion.

Cardiac (heart rate, pre-ejection period, and respiratory sinus arrhythmia), performance, and visual demand measures of driver workload were obtained from 15 male university students who drove a simulated course multiple times at a fixed speed of 72.4 km/h. The course contained curves of 3 different radii (582, 291, and 194 m) and was driven with and without visual occlusion of the road scene to manipulate driver workload. Visual occlusion of the road scene significantly reduced driving performance but did not affect the cardiac measures. Driving performance significantly deteriorated and visual demand significantly increased as curve radius decreased. The cardiac measures were differentially affected by curve radius, indicating different modes of autonomic control for the 291-m curve as compared with the 582- and 194-m curves. The patterns of dissociation across the cardiac, performance, and visual demand measures were interpreted as being capable of isolating the perceptual demands of driving from the central and motor processing demands. A potential application of this research is that the combination of psychophysiological and visual occlusion methodologies are a powerful research tool to assess performance and processing resource cost trade-offs associated with using advanced in-vehicle technologies.

Psychophysiology in Driving Research

The focus of this symposium, co-sponsored by the Psychophysiology in Ergonomics interest group of the International Ergonomics Association, is to illustrate how psychophysiological measurement can contribute to a broad sample of research issues in driving. Papers from Japan, France, and the United States will be presented that examine diverse research questions in driver workload, sleepiness, affect, and attention. The papers report how a variety of psychophysiological measures (e.g., ocular activity, and skin, cardiovascular, and electroencephalographic responses) that were obtained in research environments ranging from laboratory part-task and driving simulation to field studies can supplement and complement more traditional performance and subjective measures of driver behavior. The papers will present both past and present uses of psychophysiology in driving research as well as discuss potential uses of psychophysiology for future research.