PROPAGACIÓN INTERIOR

The idea of using multimedia to improve instruction is not new. The picture of research efforts to formally understand how best to use multimedia as an instructional tool however is hazy, complicated and somewhat lacking in cohesive focus. In this section we will describe some of the most relevant facets of the field of research.

Current computer technology gives us a high degree of freedom and control in creating instructional interfaces on the screen. We can distribute text, images, video/animations, and user controls (which naturally feedback to control the text, images, and video/animations) essentially however we choose. Tasked with using these capabilities to generate a multimedia interface that is optimized for learning, one might get a sense that there is too much freedom. Does it matter whether the text is on the right or the left? Does it matter whether this picture has text on it, or not? Should we use a video instead? The answers to these types of questions are not obvious. As researchers we might yearn for a coherent theory of multimedia instruction, which would provide experimentally verified principles of design that can be counted on, and taken into account when designing multimedia-based learning interfaces. Cognitive Theory of Multimedia Learning (CTML) represents an effort to achieve this type of theory (Mayer, 2005). CTML is heavily informed by the ideas of Cognitive Load Theory (CLT), which centers on the amount of cognitive effort required to perform tasks, and how that effort increases or decreases as the task is changed in various ways (Sweller, 2005). Central to CLT is the idea of working memory, and its finite limit. A good functional definition of working memory is the quantity of concepts that a person can concurrently work with at a given time. One of the most famous results in

cognitive psychology puts this at 7±2 (Miller, 1956). For our purposes the exact number is not nearly so important as the fact that it is finite and small. An intuitively obvious facet of working memory is that we can collapse elements together to make them easier to remember. Most of us would have trouble remembering a string of ten numbers, but few of us have trouble

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remembering someone’s telephone number, if it is required. By turning ten elements into one we have turned a hard task into an easier one. This was idea of chunking was apparent to Miller in the same research conducted in the 1950’s. CTML is based on the idea that different

instructional multimedia interventions place different amounts of cognitive load on the student and that this cognitive load can be a barrier to learning. By experimentally varying different components of multimedia instructional interventions researchers seek to identify design principles that reduce cognitive load. Researchers in CTML believe that it is possible to optimize multimedia instruction using these design principles. Many basic design principles have been proposed, primarily by Richard Mayer, mostly as a result of experiments involving problem-solving transfer tests administered shortly after instruction. Readers interested in these design principles are encouraged to reference The Handbook of Multimedia Learning edited by Mayer (2005).

Several issues arise directly when discussing CTML, the first being the generality of these principles. For example, research on the teaching of physics by Stelzer and collaborators in which a plain text instructional intervention was more effective than an intervention which used images and words (Stelzer, Gladding, Mester & Brookes, 2009) calls even the first principle into question. In this work researchers compared the efficacy of a plain text instructional

intervention, an intervention based on a popular, modern (and carefully designed) illustrated textbook, and a dynamic multimedia intervention, finding the multimedia intervention most effective followed by the plain text intervention and then the textbook centered intervention (Stelzer et al., 2009).

A second issue arises out of choosing to base CTML on CLT, and the difficulties in characterizing what exactly working memory is, and quantifying it. As has already been

discussed, ideas can be collapsed into organizational schemes that “free up” working memory for other tasks. It is likely that different people will do this in different ways. Ultimately many ways exist to think about multimedia instruction. Ascertaining which one(s) best contribute to the various facets of multimedia learning is a challenging and on-going process.

Therefore because of these difficulties and ambiguities, and despite the fact that this area of research is very much related to our research goals, we believe that our research is far more likely to contribute to the development of a better understanding of best practices of instruction with multimedia than it is that existing theories of instruction with multimedia will provide the

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answers to questions of how to best design our system. Several of the principles that are advanced by CTML researchers do seem intuitive and we certainly designed our system to reflect those principles. However, we believe that by intuitively working to build a parsimonious instructional system we likely achieved results that are as good, or better than what we might have achieved by working from these principles.

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