On the Reliability, Validity and Sensitivity of Three Mental Workload Assessment Techniques for the Evaluation of Instructional Designs: A Case Study in a Third-level Course

Cognitive Load Theory (CLT) has been conceived for instructional designers eager to create instructional resources that are presented in a way that encourages the activities of the learners and optimise their performance, thus their learning. Although it has been researched for many years, it has been criticised because of its theoretical clarity and its methodological approach. In particular, one fundamental and open problem is the measurement of its cognitive load types and the measurement of the overall cognitive load of learners during learning tasks. This paper is aimed at investigating the reliability, validity and sensitivity of existing mental workload assessment techniques, borrowed from the discipline of Ergonomics, when applied to the field of Education, Teaching and Learning. In details, a primary research involved the application of three subjective mental workload assessment techniques, namely the NASA Task Load Index, the Workload Profile and the Rating Scale Mental Effort, in a typical third-level classroom for the evaluation of two instructional design conditions. The Cognitive Theory of Multimedia Learning and its design principles have been used as the underlying theoretical framework for the design of the two conditions. Evidence strongly suggests that the three selected mental workload measures are highly reliable within Education and their moderate validity is in line with results obtained in Ergonomics.