4.3. Perceived Workload (NASA-TLX) Scores
Compared to the AR-based instruction, the average physical workload, performance, and frustration ratings were significantly higher when the participants performed the high-demanding task using paper-based instruction. Utilizing the AR instruction technique for highly demanding tasks led to a reduction of 12.18% in physical workload, 8.69% for performance, and 60.14% for frustration. In addition, when the participants performed the low-demanding task using AR instruction as compared to paper-based instruction, the average temporal demand ratings were significantly higher and performance ratings were lower. Compared to the paper-based method, using AR instruction for the low-demanding task led to lower performance and frustration ratings by 27.64% and 24.97%, respectively, and more temporal demand by 43.63%. Overall, the AR-based instruction task was found to cause a reduction of 18.13% for performance, 50.82% for frustration, and 6.50% for overall mean scores. Also, the average mental and physical workloads and temporal and frustration ratings for the two instruction methods were found to increase as the task complexity increased.Previous research on the effect of AR tools on perceived workload and performance during training has yielded inconclusive results, with some researchers claiming that using AR to deliver visual guidance and task-relevant information reduced cognitive load and increased performance [