Effects of subjective workload measurement during a workload transition on task performance

Vigilance research often includes measuring the observer\u27s subjective workload. The most commonly used NASA Task Load Index (NASA-TLX), requires several minutes to administer; typically at the end of an experiment. A more recently developed workload measure, the Simplified Subjective Workload Assessment Technique (S-SWAT), may provide researchers with further insights into perceived workload throughout a vigilance task. To date, no studies have measured workload using the S-SWAT in a vigilance experiment, specifically in the area of workload transitions. To date, only one study has examined perceived workload during a vigilance transition task; this study used the NASA-TLX. The goal of the present research was to explore the usefulness of the S-SWAT, determine how S-SWAT ratings compare to NASA-TLX ratings, and identify any effects on performance that the S-SWAT might create. Results showed that the S-SWAT had no impact on performance; this supports the potential of the S-SWAT as an instrument for better understanding the impact of task changes on perceived workload during a vigil. The S-SWAT, which is administered multiple times over the course of a vigil, provides more detail and helps identify trends of perceived workload, over time, compared to a single collection with the NASA-TLX. However, it is important to note that workload ratings on the NASA-TLX were higher when the S-SWAT was used in higher workload condition as compared to the ratings from when it was used in a low workload condition or when a control group reported workload only at the end of the vigil. While further research is needed to better understand the impact that the S-SWAT has on perceived workload, this study provides some evidence that the S-SWAT may be a useful measure throughout a vigilance task for gaining more insight into the workload experienced by observers