R We Fooling Ourselves: Does the Occlusion Technique Shortchange R Estimates?

Abstract

Summary:The occlusion technique was originally used to evaluate the cognitive demands of the roadway. Recently, the occlusion technique has been used as a cost-effective tool for assessing the visual demand of in-vehicle devices. Occlusions simulate glances from an in-vehicle device to the roadway by interrupting visual sampling. However, occluding the in-vehicle device does not impose any additional cognitive demand on the participant like true glances back to the roadway. The purpose of this study was to compare standard no-task occlusions with occlusions requiring participants to perform a visual-motor tracking task. Results suggest that overestimates of resumability may result by not including a task during occlusions. Furthermore, estimations of visual demand based on individual post-occlusion resumption times may provide a more precise measure of transition costs and resumability than measures based on Total Shutter Open Time.

Text Readability and Drivers’ Reading Time

“…The standard occlusion method has some limitations. For example, no demand is imposed on the participants while vision is occluded, unlike real-world driving where the driver should be attending the road (or another task) while not reading text (Monk & Kidd, 2007). Additionally, the goggles enforce the pace of glances, preventing long glances.…”

“…The experimental design followed the ISO 16673 standard (2007). Another occlusion metric that is often reported is the resumability ratio, R (Foley, 2008;Monk & Kidd, 2007). Due to space limitations, R is not discussed here but the potential of this metric is recognized.…”

Effects of menu structure and touch screen scrolling style on the variability of glance durations during in-vehicle visual search tasks

“…This is the reason why bench-testing or the occlusion method (ISO, 2007) may not be sufficient (see also Monk & Kidd, 2007). IVIS display designs should be tested also with self-paced actual or simulated driving with the priority in the driving task.…”

Recovering from Unexpected Lane Drifts

“…As Monk and Kidd (2007) showed in their experiment comparing the effects of an occlusion task versus no occlusion task on VCR resumption times, the presence of a simple task to occupy the participants attention to some degree resulted in higher distraction estimates according to the Occlusion Technique standard (ISO, 2007). A simple cognitive task during the occlusions was incorporated to see if there was a greater response delay or different pattern of responses to the unexpected lane drift.…”