Coherence Principle Description
The coherence principle essentially states that superfluous material, in the form of visuals, audio or text, should be avoided when preparing a multimedia lesson (Clark & Mayer, 2008, p. 153). In each of these cases, there is support for the idea that the extra information that is not directly related to the learning objectives can distract the learner and hinder the learning process.
The most important aspects of the coherence principles focus on the avoidance of extraneous material. In terms of audio, it is best to avoid the inclusion of background music or sounds in a lesson. With a limit to the amount of working memory a learner has, the background music or other sounds can lead to overload of the working memory and hinder learning. Eliminating or avoiding superfluous graphics is also recommended. While graphics related to the learning objectives are important to include, adding graphics not related to those objectives for the purpose of “spicing up” the lesson causes the learner to divide their attention between the learning material and the graphics. When graphics are used, they should be simple in nature to improve the learning process. Detailed graphics may depress learning, especially among beginners in a particular subject. Lastly, it is best to avoid the use of extra words. Words added to interest learners, expand on ideas or go into technical detail can all be distracting for the learners and hinder the learning process.
Examples of Coherence Principle
An example of successful adherence of the coherence principle is the following slide from the instructor materials from Campbell Biology, the support site for the Biology textbook by Neil Campbell. The slide presents a clearly identifies the “key to flight” as “aerodynamic structure and provides an image that illustrates this structure in a simple, relatable way. In addition, the slide avoids going into the technical details of the airfoil in either words or images. This allows the learner to come away with the simple idea that it is the structure of a wing that allows a bird to overcome gravity.
Another source provides an example of suspect adherence to the coherence principle. In the slide below from a slideshow on evolution, focus is on Lamarck’s contribution of evolution theory. While the limited text implies that this slideshow is being used while a teacher narrates, there is also the inclusion of a picture (perhaps one of the students) and the words “Are you still paying Attention?” Both of these seem to be an attempt to retain the attention of students, but as they do not directly relate to the information being related, serve only to distract and disrupt the learning process. They most certainly do not add to the learning experience for the student, nor do they effectively make the material more interesting.
Relationship of Coherence Principle to Other Multimedia Principles
Prior principles discussed include the multimedia principle, which states that learners benefit from having words and images together, rather than words alone, and the contiguity principle that states that those included images should be relatively close to the words to which they are related. In short, these principles state that images should be included and be close to the words they are illustrating. The relationship this has to the coherence principle is something like a reality check for image inclusion (or other media such as audio). It is important to include multiple forms of media to allow users to access both auditory and visual learning channels, however, it is equally important to be sure that the images (or audio) serve a specific purpose. Images must be related to the learning objective. If they are not, the benefits of adherence to the multimedia principle may, in fact, be contradicted by the lack of adherence to the coherence principle.
Coherence Principle Related to Psychological Theories
Beginning with arousal theory, many instructors seem to face the challenge of keeping the attention of the learner. To do this, they make attempts to grab or keep attention through the inclusion of “exciting” images, “fun” audio or “interesting” facts or stories. Arousal theory assumes that the learners will become emotionally engaged and, therefore, have greater interest and focus in the main learning material (Clark & Mayer, 2008, p. 156). In many ways, it seems like arousal theory makes perfect sense. If I am attentive to the screen, thanks to the included media, I must be attentive to the topic at hand. Cognitive theory, however, contradicts this. Essentially, it comes down to the idea that we must process information through our working memory and that working memory has limited capacity. Inclusion of images that do not specifically and coherently relate to the learning objectives will utilize some of the working memory space and may overload the working memory. This would lead to decreased learning, rather than increased. The dual-coding theory goes on to imply that improved learning comes from utilizing both the auditory and visual channels (Moreno & Mayer, 2000). An example of this might be using an image along with narrated text.
My View of the Coherence Principle
The aspect of the coherence principle that strikes me as being right on target is that the illustrations used in a multimedia presentation should be simple in nature. As a science teacher, I am faced with the constant challenge of helping students to better understand complex systems. Clearly, images and video go a long way towards helping a student visualize a process such as muscle contraction. However, there exists a wide variety of diagrams that can show this. Diagrams that are simple and focus on few specific details help beginner students to pay attention to the process in general without getting lost in the details.
The one aspect of this idea that I would say warrants qualification is that not all students possess the same knowledge base. Advanced students, who may already have an understanding of the basic ideas, would likely benefit, or at least not be distracted by, a more detailed view of this same material. They key to this is that the advanced students have prior understanding of the material to link the details to, whereas the beginner students do not.
Campbell, N. A., & Reece, J. B. (2001). Campbell Biology. San Francisco, Calif: Benjamin Cummings.
Clark, R. C., & Mayer, R. E. (2008). E-learning and the science of instruction, 2nd edition. Pfeiffer: San Francisco, CA.
Mayer, R. E. (1999). Multimedia aids to problem-solving transfer. International Journal of Educational Research, 31(7), 611-623.
Moreno, R., & Mayer, R. E. (2000). A learner-centered approach to multimedia explanations: Deriving instructional design principles from cognitive theory. Interactive Multimedia Electronic Journal of Computer-Enhanced Learning, 2(2), 2004-07.
Campbell Biology Online (subscription needed)