Cross-adaptive operator loading tasks.

Abstract

Performance measures often fail to indicate the amount of effort expended by an operator in reaching various levels of task performance. Secondary or loading task techniques have been developed to overcome this problem. However, with the loading task technique, a problem of interpretation arises when both primary and secondary task measures vary with operator performance. The cross-adaptive operator loading technique, which automatically adjusts the difficulty level of the loading task on the basis of primary task performance, is suggested as a solution to this problem. Data are presented which demonstrate that the cross-adaptive technique effectively standardizes scores on the primary task while casting all the variance in performance to the loading task scores. The cross-adaptive secondary scores thereby become a single unambiguous and sensitive index of effort expended to reach a pre-established level of task performance. Procedures for the implementation of the cross-adaptive techniques are discussed and guidelines for its use are suggested.