The Effect of Delayed Report on Subjective Ratings of Mental Workload

Abstract

Forty-eight subjects performed a short-term memory task with several difficulty levels and provided either immediate or delayed ratings of workload via the Subjective Workload Assessment Technique (SWAT). Mean SWAT ratings did not vary significantly as a function of delayed report, but a substantial number of subjects gave delayed ratings that were discrepant from their immediate ratings. A counterbalancing effect in delayed ratings appears to have been a factor in the failure of the delay effect to reach significance. A secondary objective of this study was to examine the sensitivity of SWAT in a between-subjects design. SWAT ratings varied significantly as a function of task difficulty manipulations, supporting the sensitivity of SWAT to the workload of the conditions used.

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