e-Learning and the Science of Instruction

CHAPTER 8 Applying the Coherence Principle Adding Extra Material Can Hurt Learning

CHAPTER SUMMARY

Perhaps our single most important recommendation is to keep the lesson uncluttered. In short, according to the coherence principle, you should avoid adding any material that does not support the instructional goal. The coherence principle is important because it is commonly violated, is straightforward to apply, and can have a strong impact on learning. Mayer and Moreno (2003) use the term weeding to refer to the need to uproot any words, graphics, or sounds that are not central to the instructional goal of the lesson. In spite of our calls for conciseness, you might be tempted to embellish lessons in an effort to motivate learners. For example, in order to counter high e-learning dropout rates, some designers attempt to spice up their materials by adding entertaining or motivational elements such as dramatic stories, pictures, or background music. Our advice is: Don’t do it! In this chapter we summarize the empirical evidence for excluding rather than including extraneous information in the form of added text, added graphics, and background sound. When learners use their limited processing capacity on extraneous material, less capacity is available for making sense of the essential content. What is new in this chapter is some updating of the growing research base, but the main conclusion remains the same: Adding interesting but unnecessary material to e-learning can harm the ...