Measurement of cognitive load

Cognitive Load Theory (CLT) has been a remarkable instructional theory that facilitates learning for over three decades. The theory has its ground in the studies that have examined what happens in cognitive processes when working memory and long-term memory interact (Sweller, Ayres & Kalyuga, 2011). This interaction obviously affects learner's performance and learning as an outcome. Granted that too much cognitive load is created for some reasons such as complexity of material or poor or inefficient instructional design of the material, the outcome is jeopardized as insufficient working memory resources manage to carry out processes required to learn. CLT has successfully presented barriers to learning and proposed strategies like modality effect to deal with the difficulties (Sweller et al., 2011). When CLT was born, one of the basic concerns was how to measure the construct. Several measures such as error rates, time on task and dual task methods were applied until a self-rating measure was created by Paas (1992). This measure has been a hit in the field of cognitive psychology; however, after a while it received some criticism. It was basically designed to ask for learners' perceptions of their invested mental effort on a task while learning and taking tests. The criticism has been centred on the nature of the measure itself that it is a subjective measure and all three types of cognitive load cannot be measured by this single subjective measure. Additionally, it has been stated that there have been several variations in labels and items of the scale as well as administration time and frequency. Responding "timing and frequency" issue and meeting the criticism, Gog, Kirschner, Kester, and Paas (2012) have worked on the effects of timing and frequency on cognitive load measures. They collected invested mental effort ratings when each problem solving task in a set is done and compared them with the mental effort measured once at the end of the set. The findings confirm that the frequency affects the value of the mental effort and the accurate data can collected through repeated and consistently administered measures. This finding will likely help set up the conditions that can provide an accurate and reliable results.

Reference:
Paas, F. (1992). Training strategies for attaining transfer of problem-solving skill in statistics: A cognitive-load approach. Journal of Educational Psychology, 84, 429–434.
Sweller, J., Ayres, P., & Kalyuga, S. (2011). Cognitive load theory. New York: Springer.
Van Gog, T., Kirschner, F., Kester, L., & Paas, F. (2012). Timing and frequency of mental effort measurement: Evidence in favor of repeated measures. Applied Cognitive Psychology, 26, 833–839.