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"9 Ways to Reduce Cognitive Load in Multimedia Learning" (Mayer & Moreno, 2003)
This paper by Mayer and Moreno addresses the problems inherent of using multimedia when teaching. The author propose a theory of multimedia learning based on 3 assumptions: the dual-channel assumption, the limited-capacity assumption, and the active-processing assumption. The dual-channel assumption asserts that humans process verbal and visual in separate systems. The limited-capacity assumption asserts that a limit exists as to the amount of information each system can process at any given time. The active-processing assumption asserts that meaningful learning represents necessitates higher cognitive processes such as building connections between verbal and visual representations of information. Based on these assumptions, the authors put forth the idea of Cognitive Overload which occurs when a learner's cognitive capacity is exceeded by the amount of cognitive processing desired by the learner. Having identified the problem of Cognitive Overload and the assumptions made, the authors proceed to propose several ways of alleviating it. These ideas/theories are as follows:
Modality Effect - students show better comprehension of concepts presented as diagrams/animations when they are presented with narration rather than text.
Segmentation Effect - students show better comprehension of multimedia explanations when it is presented in paced, student-controlled segments rather than a continuos presentation. This way, the student can make sure they understand one concept before being presented with another, presumably more complex one.
Pretraining Effect - students show better understanding of a multimedia explanation when they are presented with background information (i.e. relevant jargon) prior to the lesson. An example of this would be providing a list of relevant vocabulary prior to powerpoint lectures.
Coherence Effect - students show better understanding of multimedia explanations when they lack extraneous information, sounds and images. It is believed that unnecessary factors 'take up' cognitive processing away from necessary ones.
Signaling Effect - in multimedia presentations that do cannot exclude extraneous information, students show better understanding when educators include signals as to what information is important (i.e. bolding important terms or underlining them).
Spatial Contiguity Effect - student understanding is better when text is placed near the image it corresponds to.
Redudancy Effect - comprehension is negatively affected when on-screen text mirrors lecture. For example, an explanation of diminishing marginal utility is given by a professor, but also concurrently presented in text on a powerpoint slide.
Bartsch & Cobern, 2003. This study, titled "Effectiveness of PowerPoint Presentations in Lectures," examined the differences in preference, perceived learning and test performance between class units taught using transparencies, a basic powerpoint presentation and an advanced powerpoint presentation including images and sounds. Students were surveyed directly after each lecture and at the end of the course and performance was measured using class averages on assessments administered for each unit. The study found no significant difference in preference between the three modes of presentation for end-of-class ratings, but a preference for powerpoints in the end-of-semester ratings. Students believed they learned more from both types of powerpoint presentations than from transparencies. It was found that students performed about 10% worse on the units taught using the advanced powerpoint presentation that included images and sounds. Upon this finding, researchers decided to examine the effect of relevant and irrelevant powerpoint images on test performance and enjoyment. Participants were shown 30 slides that included a fact and an image that was either relevant or irrelevant to the fact. Afterwards, participants were given a test on the slides' information. It was found irrelevant images had a significant negative effect on both performance and enjoyment. On the other hand, relevant images had neither a negative nor positive effect on performance and enjoyment of the material. Click here to see the study.
Jamet & Le Bohec, 2006. This study, titled "The Effect of Redundant Text in Multimedia Instruction," examined the interactions of redundant text and spoken information in cognitive psychology students learning different theories of memory. A lecture was presented to the students. This lecture was accompanied by a powepoint-style presentation that included a diagram of the memory theory being taught and no text (no redundancy), text (redundancy: text mirroring the entire lecture presented all at once), or sequential text (text mirroring the text was presented sequentially, after being spoken). Students were then assess on information retention, transfer (applying the information learned to more abstract situations) and diagram completion. Students in the non-redundant group significantly outperformed students in the redundant conditions, both full text and sequential text. No significant differences were observed between the full text and sequential text conditions, suggesting that redundancy itself plays the negative role, regardless of the order in which redundant information is presented. Click here to see the study.