Abstract

NASA Task Load Index (NASA-TLX) is widely used in the research community to evaluate the subjective workload of a task. It is a multi-dimensional rating scale supporting the assessment of subjective workload with task-related skills (mental demand, physical demand, temporal demand), behavior-related skills (performance, effort), and subject-related skills (frustration). Yet, the NASA-TLX questionnaire has some shortcomings, one potentially being the subjective interpretation of the subscales. In the official NASA-TLX documentation, each subscale has a short description formed as a question directed to the participant. However, no clear definitions or examples describe the subscales, which might result in a subjective interpretation of a subscale’s meaning by the participant, potentially varying from the intended meaning. Participants might additionally evaluate the subscale wrongly due to their subjective understanding and also encounter difficulty in distinguishing the subscales from each other due to the high correlation between the subscales and no clear explanations. In comparison to NASA-TLX, another subjective workload assessment tool called SWAT already teaches the definitions of its subscales through additional explanations and examples. Thus, one potential solution to this problem can be introducing teaching as a tool to help participants learn the meanings of NASA-TLX subscales before conducting the experiment and the final NASA-TLX evaluation. The teaching can be implemented in various ways, including textual explanations, video explanations, and interactive task-based activities. This research paper focuses on implementing the teaching methods of video explanations and an interactive task-based activity as a phone application, which participants can use as a pre-training step before the actual experiments to learn more about NASA-TLX subscales. The application explains the meanings of the subscales through a baseline comprising the original question-based definitions of NASA-TLX subscales, dedicated video lectures explaining each subscale in detail, and engaging participants through an interactive task-based activity. The task consists of a game designed to align with individual subscales of the NASA-TLX questionnaire. The game is built to be extensible, allowing the usage of multiple subscales at once to simulate the combination of different subscales. The phone application is developed through an iterative co-designing process with multiple experts, ensuring the best explanations of the NASA-TLX subscales. The phone application can be used to learn the definitions of each subscale and the ability to distinguish between the subscales, especially in tasks where the correlations between the subscales are high. The results can be used to study the effects of dedicated teaching methods on the final subjective workload of a task. Additionally, the different teaching methods can be evaluated individually, establishing the best teaching approach.

Results/Implementation/Project Description

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