Visual attention in driving: The effects of cognitive load and visual disruption

Objective: This study investigates the effect of cognitive load on guidance of visual attention. Background: Previous studies have shown that cognitive load can undermine driving performance, particularly drivers' ability to detect safety-critical events. Cognitive load combined with the loss of exogenous cues, which can occur when the driver briefly glances away from the roadway, may be particularly detrimental. Method: In each of two experiments, twelve participants engaged in an auditory task while performing a change detection task. A change blindness paradigm was implemented to mask exogenous cues by periodically blanking the screen in a driving simulator while a change occurred. Performance measures included participants' sensitivity to vehicle changes and confidence in detecting them. Results: Cognitive load uniformly diminished participants' sensitivity and confidence, independent of safety relevance or lack of exogenous cues. Periodic blanking, which simulated glances away from the roadway, undermined change detection to a greater degree than did cognitive load; however, drivers' confidence in their ability to detect changes was diminished more by cognitive load than by periodic blanking. Conclusion: Cognitive load and short glances away from the road are additive in their tendency to increase the likelihood of drivers missing safety-critical events. Application: This study demonstrates the need to consider the combined consequence of cognitive load and brief glances away from the road in the design of emerging in-vehicle devices and the need to provide drivers with better feedback regarding these consequences.