Background and Objectives: Today, it is common to use multimedia in foreign language teaching. There are some principles for designing multimedia that would reduce task cognitive load. These principles are based on the cognitive load theory. The methods of cognitive load measurement are divided into two categories, namely the subjective and objective measurements. NASA-TLX is an example of the subjective measurements; methods such as electroencephalography and eye-tracking are among the objective measurements. Due to the advantages of objective measurements, using these methods is common in cognitive studies. Eye-tracking technology can record different eye-movements of humans such as pupil dilation, saccades, fixations, blinks and microsaccades with a high sampling rate. These measurements are being widely used in cognitive and mental workload studies. In this paper, the cognitive load in multimedia language learning has been evaluated, using eye-tracking data analysis.
Methods: Two multimedia versions for teaching English were produced with the same narration and the length of 342s. In one version, the principles in designing multimedia were applied whereas in the other version, they were violated so that more cognitive load in comparison to the former version could be imposed. Ten subjects whose English listening comprehension was assessed with a simulation of the International English Language Testing System (IELTS) participated in the experiment and were randomly divided into two equal groups of five. The two groups were homogeneous with respect to their listening proficiency. One group watched the multimedia without principles while the other group watched the multimedia with principles. Then, each individual answered 12 multiple choice questions about the concepts presented in the multimedia as a performance test. During watching the multimedia and taking the performance test, the participants’ eye movement data were recorded. Then, each person filled out the NASA-TLX Questionnaire. Based on the results of the performance test and the NASA-TLX, the difficulty level of the multimedia without principles as compared to its version with principles was evaluated. The collected data were divided into blocks of 30 seconds.
Findings: Based on the NASA-TLX, the group who watched multimedia without principles experienced more cognitive load in comparison to the group who watched multimedia with principles, which approved our assumption about the higher load of the multimedia without principles. However, no significant difference was found in the results of the performance test between the two groups. According to statistical analyses, the pupil diameter, saccade length, saccade velocity, blink latency, and microsaccade amplitude in the multimedia blocks of both groups were significantly different. Nevertheless, no significant difference was found between the two groups in terms of the fixation time, the fixation rate, and the microsaccade rate.
Conclusion: Based on the findings of this study, pupil dilation, saccade length, saccade velocity, blink latency, and microsaccade amplitude have a significant relationship with the amount of the load imposed by the instructional multimedia which corresponds to the literature review of the study. Based on the results of this study, along with the subjective methods, eye movement data can also be considered as an appropriate tool for assessing the cognitive load imposed by multimedia learning and qualifying the multimedia instructional content. A significant difference was also found between the two groups in the study in terms of their blinking rate. More investigation and different experiments are needed for examining other eye movement criteria that have been investigated in this study, including fixation time, fixation rate, and microsaccade rate so that a more definitive conclusion would be reached regarding a significant relationship between these parameters and the mental load imposed by the multimedia English teaching.
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