compete for the learner’s attention and detract from learning. Visual displays that are hard to read or spoken presentations given in noisy environments can compromise learning because they draw attention away from deeper processing of meaning.
Providing structure and organization is important to help learners understand concepts and how they relate to each other. The format used depends on the relationships that will be depicted; outlines can be used to show structural hierarchies, and tables can organize ideas in two or three dimensions, while diagrams can help convey more complex relationships among ideas. Materials and lesson plans also should be organized so that related elements and ideas are presented near each other in space and time. For example, an explanation should be given at the time a concept is depicted rather than many minutes, hours, or days later. In addition, new material should be presented in discrete units so that new learners are not overwhelmed with too much new information at once.
Use multiple and varied examples and formats. If knowledge, skills, and strategies are acquired in multiple and varied contexts, learners can better apply the knowledge across a range of tasks and situations. Memories can be triggered by multiple cues, so that knowledge is available when needed. Learners may acquire knowledge more slowly this way, but retain and transfer it better than if they had learned it in only one context. For example, effective vocabulary instruction focuses on teaching the multiple meanings of words and the varied forms they take; it also provides ample opportunities to encounter and use words in many different contexts.
However, implementing this principle must be balanced against the preceding principle: The amount of information should not overwhelm the learner to the point of attention being split or cognitive capacities being overloaded.
Space presentations of new material across time. It is better to distribute the presentation of materials and tests over time than to concentrate the learning experiences within a short time span. For example, when studying new vocabulary words, it is better to space the same amount of study over days or weeks—and to use the words in varied contexts such as reading, speaking, and writing—than to cram it into a single study session. Re-exposure to course material after a delay often markedly increases the amount of information that a student remembers.
Test on multiple occasions, preferably with spacing. There is substantial evidence that periodic testing helps learning and slows down forgetting. Regular quizzes, which can be quite brief and embedded in instructional materials, keep students constantly