The Assessment of Workload: Dual Task Methodology

The present paper outlines three major assumptions often implicitly assumed in dual task experiments conducted to assess operator workload. These assumptions are shown to be incorrect. Three criteria which should be met in dual task experiments that draw inferences from secondary task decrements are discussed. An experiment, meeting the proposed criteria, was conducted which demonstrated that when the criteria are met secondary task performance can be predictive of primary task difficulty. However, the data also indicate that a simple assessment of effort alone will not predict total task performance.