|
About the AuthorJoseph Friedman was born and raised in Los Lunas, New Mexico. He graduated from New Mexico Tech in 2010. He now works doing freelance marketing for local Albuquerque rock bands. Contents |
Literature ReviewScreencasting literature is limited; therefore, it is necessary to look at the literature that applies to the basic building blocks of screencasts. A screencast is considered multimedia because it is a combination of mediums, so relevant research on multimedia and the applications for screencasting are discussed here. First, it is important to understand how people learn with multimedia and how multimedia can be crafted to effectively convey a message to a learner. Second, literature on effective documentation is discussed as well as the use of multimedia documentation. Finally, screencasting as it stands today will be discussed and the common genres of screencasts highlighted. Learning with Multimedia Using a cognitive architecture, it is simple to visualize how people think and learn (Reed). These models have evolved over the years, as understanding of the human mind and how it learns expands. The most popular model of learning in a multimedia environment was first described in 2003 by Mayer and Moreno. Later, in 2006, Moreno proposed the Cognitive Theory of Learning with Multimedia (Figure 1). The main theories that are applicable to screencasts in these models are dual coding, cognitive load, and active processing.  Figure 1 - Cognitive Theory of Learning with Multimedia (Moreno, 2006) Dual coding theory, first theorized by Pavio (1986), is the idea that humans possess separate processing channels for verbal and visual information. The verbal channel processes narration and audio, while the visual channel processes text, images, illustrations, and nonverbal sounds. These systems are independent of each other, meaning either can operate without the other or they can work in parallel. Information processed by both channels is called referential processing, and this has an increased effect on recall (Mayer & Anderson 1991; Paivio 1991). When both channels are working in parallel, the user is most effective at understanding, connecting, and organizing the information. Cognitive load theory is the idea that each of these channels can only process a limited amount of information (Chandler & Sweller). In 1971, Hsia came to several conclusions while doing a review of dual and single coding theories. Human information processing functions as a multiple-channel system until the capacity of the system is overloaded; when the input becomes greater than the system’s capacity, the system reverts to a single channel system. This means that an increase in the amount of information presented does not necessarily increase the rate of information transmission. When the system is overloaded, two types of cognitive load can occur: intrinsic and extraneous. Intrinsic cognitive load happens when the information is too complex or difficult and extraneous cognitive load depends on how the information is presented (Mayer & Anderson 1991). Active processing is the idea that learning requires substantial processing in the verbal and visual channels. Active processing occurs in the working memory, or short term memory. The average human can deal with five to nine chunks of information in working memory at a time. If the user becomes distracted or overwhelmed by the information, cognitive load can occur. There are ways to avoid unnecessary cognitive load and increase active processing, explored by Mayer and Moreno (2003). There are nine load-reducing methods, most of which are applicable to screencasts, the especially important ideas are off-loading, segmenting, weeding, eliminating redundancy, and synchronizing. Learning in a multimedia environment is most effective when cognitive overload is accommodated. Off-loading reduces cognitive load by moving essential processing from the visual channel to the auditory channel, this means that better learning happens when words are presented as narration rather than on-screen text (Mayer 2002; Kalyuga). Off-loading of essential information from the visual channel to the auditory channel can be easily applied to screencasts. On-screen text can be reduced to a minimum by adding effective narration. The narration of a screencast should compliment and expand upon the visuals. Segmenting reduces overload by allowing time between successive segments of information, this is best when the learner can control the pace. Segmenting can be accommodated by screencasts as well. Concepts within an individual screencast can be segmented by simply moving at a consistent pace. Providing space between concepts also ease the editing process, allowing the narration to easily line up with the video. Larger concepts can be segmented into several screencasts. Weeding is the elimination of extraneous material so the learner will not have to process that information. Extraneous material in this sense may be interesting, but is ultimately irrelevant to the task at hand. Weeding can also easily be applied to screencasting. Individual screencasts that deal with one or two specific concepts should not include extraneous information. It is also important to eliminate redundancy, because the presentation of identical streams of printed and spoken words can cause cognitive overload. Eliminating redundancy is different than weeding because it involves the cutting of unneeded material, namely eliminating text that matches the narration. Synchronizing is the presentation of narration and animation simultaneously, which may seem obvious when viewed through the lens of screencasting. Every screencast can accommodate cognitive load reducing principles. Some load reducing principles may seem inherent in screencasting, but they are important to understand. A screencast designed with the intent to reduce cognitive load will communicate its message more effectively than one that is not because the user can more easily concentrate on the information. Screencasts provide support for users in the same way that documentation does, and, as documentation evolved from print to electronic, a lot was learned about creating effective documentation. The principles of effective documentation, like the cognitive psychology principles discussed above, can shape the way we approach screencasting. |