The Playback Method of Protocol Analysis Applied to a Rapid Aiming Task

Abstract

The analysis of subjective verbal protocols can provide valuable information additional to that obtained from traditional objective data sources. The most frequently used type of protocol analysis is of the “think-aloud” report where operators verbalize as they perform a task of interest. However, while this concurrent method has been usefully applied to high-level cognitive tasks that are accomplished over extended time periods, it is generally considered to be less appropriate for short-duration tasks where the emphasis is on speed of performance. This study reports on the application of a new protocol method to a speeded task based on a procedure where the computer “plays back” the experimental trials and shows the subject's response. The verbal response of the subject was recorded during the playback, augmented by prompts from the experimenter. Several aiming tasks requiring rapid movements to a target were examined using this method. The data obtained from the protocol analysis were a valuable adjunct to the actual performance results, and demonstrated that the new method appears to be a satisfactory procedure for obtaining protocols for rapidly performed tasks. Where movements involving both hands were involved, the verbal protocols supported a divided attention hypothesis for performance over a competing motor-program hypothesis. The reports implied that the movement characteristics were under conscious control requiring division of attention.