Comparing the effects of Merrill & Gagne’s instructional design models on cognitive load, learning and instructional efficiency

With the increasing importance of instructional multimedia and the use of their interactive and unique features in the teaching-learning process, we are witnessing the design and production of this technology and its use in teaching courses and different levels of the educational system. Cognitive load theory, as one of the theories related to information processing, is one of the most effective theories in instructional design and an effective guide for designing multimedia and other instructional materials. The basic premise of this theory is that learners have very limited working memory capacity to process when facing with new information. The purpose of this theory is to predict learning outcomes by considering the capabilities and limitations of human cognitive structure. Cognitive load theory is based on the idea that the design of instructional materials should be based on our knowledge of how the human mind works. Based on this assumption, the various processes of acquiring knowledge and understanding are explained based on the load they place on the human cognitive system (which is an active system with limited information processing capacity). Because this theory links the design features of instructional materials to the principles of human cognitive processing, it can be used in a wide range of learning environments.The present study aimed to compare the effects of Merrill and Gagne's instructional design models on students' cognitive load, learning and instructional efficiency in Science lesson.

The study was quasi-experimental with pretest and posttest design with two experimental and one control groups. The statistical population consisted of all male students of the sixth grade elementary school of Qazvin. The sample including three 30 students’ classes were selected through convenience sampling procedure and the classes randomly assigned to experimental and control groups. The materials and instruments included instructional multimedia contents, learning tests, and cognitive load assessment scale. The first experimental group studied the multimedia based on the Merrill model, the second group studied the multimedia based on the Gagne model and the control group studied non-model multimedia. Data were analyzed by using analysis of covariance (ANCOVA).

The results of the study showed that multimedia based on the Merrill instructional design model compared to multimedia based on Gagne instructional design model and non-model multimedia, has led to less cognitive load, more learning and instructional efficiency. Also, multimedia based on Gagne's instructional design model compared to non-model multimedia led to less cognitive load, more learning and instructional efficiency.

One of the concerns of educational designers in the process of designing the content of multimedia educational materials and other learning materials has always been focused on the appropriate selection of instructional design models. Since there are different models for instructional design of learning materials, to choose a suitable model, one should rely on theoretical foundations and the results of research conducted in various theoretical areas, including cognitive load theory. According to the findings of this study, it is suggested that in order to reduce the cognitive load and increase students’ learning, Merrill instructional design model would be used in designing instructional multimedia content.