The Effect of Intervening Task Performance on Subjective Workload Ratings

Abstract

Thirty subjects performed a short-term memory task and used the Subjective Workload Assessment Technique (SWAT) to provide workload ratings under one of five conditions. Ratings were provided either immediately following task performance, after a delay period during which no additional tasks were performed, or after a delay period during which an additional set of memory tasks at one of three levels of difficulty was performed. Neither the delay interval nor the requirement to perform a set of intervening tasks significantly affected mean SWAT ratings relative to the immediate rating control condition. Patterns in the data suggested that performance of a set of difficult intervening tasks had the greatest tendency to affect memory task ratings, and indicate that the potential influence of intervening task performance should not be completely discounted in workload rating scale applications.