Less is More
Less is more, especially when considering long-term retention and transfer.
In an age where knowledge is power and all types of information are readily accessible, curriculum tends to cover a broad expanse of domain content. Consequently, students end up carrying books that sometimes weigh as much as they do. They may be exposed to more content but do not necessarily know how to apply this knowledge effectively nor have developed deep conceptual understanding.
There are several reasons why presenting less but more meaningful information may promote better retention and transfer. Consider both the nature of learning and of the learner. Effective learning is often effortful. Whether in retrieving information from memory with minimal cues, learning material given variable conditions, or re-representing information, when more effort is put into learning, the generalization and retention of learning are generally enhanced (see Principles: Practice at Retrieval, Varying Learning Conditions, and Re-representing Knowledge).
Now consider the characteristics of a learner. While learning a person mainly processes information that is either visual or auditory, and is limited in the amount of information that he or she can process at any one time regardless of the type of information (Baddeley, 2002). When too much information is presented to be effectively processed, we say that a person is experiencing "cognitive overload."
Mayer and Moreno (2003) offers suggestions on how to reduce cognitive overload in a multimedia instructional setting so that learning will not be impaired. Several of these suggestions are also applicable to general instruction, including segmenting (i.e., breaking down information into successive chunks) and weeding (i.e., eliminating interesting but extraneous material). These suggestions have been shown to improve learning in a variety of experimental settings.
Typically instructors aim to have learning generalize to other contexts and beyond the timeframe of instruction. Designing curriculum, thus, involves predicting what learners will need to know in the future and what level of detail is necessary, and then reconciling these learning objectives with the nature of learning and learners' characteristics.
Generally speaking, emphasizing deep understanding as opposed to covering a broad range of topics leads to improved long-term retention and transfer. However, developing a cursory knowledge of topics may sometimes be all that is be desired. Whatever the learning goals, instructors and students should be conscious of these goals so that they can teach and learn in ways that best achieve either in-depth or broad coverage.
The demonstration for this principle is currently being developed.
Be aware of the trade-offs between depth and breadth of content coverage. Make learning objectives explicit to students and aligned with the nature of the content covered and with the form of evaluation. (For more information on aligning learning objectives with appropriate assessment tools, refer to Stolovitch & Keeps, 2002; and Wiggins, 1998 in the Principle: Avoid Passive Learning).
Baddeley, A. D. (2002). Is working memory still working? European Psychologist, 7, 85-97. This paper reviews empirical data concerning a model of working memory proposed in 1974 and presents an updated model. In addition to the central executive, visuospatial sketchpad, and phonological loop, the new model contains links to long-term memory and an episodic buffer.
Mayer, R. E., & Moreno, R. (2003). Nine ways to reduce cognitive load in multimedia learning. Educational Psychologist, 38, 43-52. Although this paper discusses empirically-based strategies for reducing cognitive load in multimedia instruction, several of these strategies (e.g., segmenting and weeding) are applicable to instruction in general as reducing cognitive load will typically enhance learning. Effective learning will always require weeding out irrelevant information while focusing cognitive resources on more relevant information.