Wetzel, C. Douglas, Radtke, Paul, H. and Stern, Hervey W. (1994) Instructional effectiveness of video media. Lawrence Erlbaum Associates, Publishers. USA.
Chapter 3
- The primary focus of this chapter is on how those two sources of information affect comprehension in dynamic presentations. The first part of this chapter examines this focus under three subtopics; educational studies on combining visual and verbal material, studies of visual and verbal information in news broadcasts, and studies that bear on the interrelation of comprehension and attention. The final part of this chapter briefly reviews the literature on the use of static visual illustrations in text in terms of several generalizations relating to the use of visuals in video presentations . P40
- Visual and auditory information are used in typical educational video presentations in a multiple media format that requires the viewer to watch still or dynamic visuals and listen to narration and other sounds. P40
- Television comprehension would be defined in terms of the ability to process parallel audio and visual information channels and to integrate their information semantically. P40
- When information is presented by audio, there is a disadvantage to having it precede the viewing of visual information –it is better to hear a narrative after seeing visual information The authors (Baggett and Ehrenfeucht, 1983) suggested that auditory verbal information is not as readily retrieved or associated with visuals as is textual verbal information, which may be processed relatively more like visual information. Taken together, these results suggest that there is little competition for resources when visual and auditory information are presented simultaneously. P42
- Performance was found to be best when the visual and auditory information were presented simultaneously and when the visual information preceded the auditory information by 7 seconds. Those conditions presenting the audio before the visuals produced the worst performance, declining as more time elapsed between the audio narration and the visuals. P42
- In one experiment, redundant information was presented by either video, audio, or text shown in the video. P43
- Narrative and video were constructed to be relevant to one another, but not redundant. P43
- …combined audio-video presentations led to performance on either visual or verbal information that was as good as that with audio-only or visual-only presentations. Thus, visuals did not interfere with learning the narrative information, and the audio presentations did not interfere with learning visual information. Taken together these experiments indicated that visual, audio, and textual channels containing the same information allowed learning from each, but learning was maximized by combining pictures with text or audio. P43-44
- Two studies by Pezdek and her associates suggest that television comprehension is related to visual/spatial abilities, and that the general cognitive processes involved in reading and television comprehension come to overlap with increasing age (Pezdek 1984). P47
- Combining visual and verbal information in video presentations generally leads to either equal or better learning compared to when these sources are given alone. These were typically comparisons of audio and video visual presentations. Studies varying the order of presenting visual and verbal information suggest the primacy of visual information and the need to carefully match the two sources of information. Learning is best when they are presented simultaneously or when the visuals precede the narration by up to 7 seconds. Presenting narration in advance of casuals appears to be detrimental . P50
- “people cam construct a mental representation of the semantic meaning of a story from either audio or visual information alone, but appears that when presented together each source provides additional, complementary information that retains some of the characteristics of the symbol systems of origin (Kozma 1991: 192) P53
- The finding that combined visual and audio information leads to better or equal learning in video presentations is generally interpreted to mean that these sources do not compete for processing resources. P53
- News broadcasts are one of the primary exceptions to the perception that adult television viewing is for entertainment purposes. P54
- Typical television news stories are presented in such a way that comprehension is often difficult. The verbal stories are short, making it difficult to convey much information, to provide explanations, or to establish a context. Learning is also constrained by the short duration of the visuals, the large number of visuals, and the number of visuals that represent stereotypes that are not related to verbal content. P53
- Those aspects of a television news broadcast that do deal with topics about which viewers already have some knowledge tend to be remembered better as are personally relevant stories given in an audio-only radio broadcast format. Viewers are also more likely to recall information from summary statements and from violent stories and less likely to recall information from similar topics groups together. P53
- Son (1987) found better retention for news stories with well-synchronized narration and pictures compared to when the same content was altered to disrupt the synchrony of the narration and pictures. They also found the addition of a recap of the main point of a news item benefits retention. P55
- Observations of children watching television indicate that attention is discontinuous and periodic P58
- Formal features are visual or auditory techniques and events such as the level of action, pace, zooms, perspective changes, unusual sounds and so forth. It has been found that viewer attention is gained and maintained by such attributes as auditory changes, women’s and children’s voices, peculiar voices, sound effects, laughing and applause, camera cuts, and women characters. Some attributes that inhibit attention are extended zooms and pans, animals, still pictures and male voices. Many of these are auditory attributes that serve to cue visual attention because they are associated with and predict content shown on the screen. P58
- The importance of audio lies in the fact that viewers can always hear a program, buy may not always see the screen except peripherally. P58
- The reactive theory reflects popular opinions characterizing the viewer as a passive recipient that is acted on by television. That the viewer’s reactions are controlled by manipulating the superficial characteristics of the medium seems to justify typical professional production techniques. Thus, television is seen as having the ability to capture and sustain the viewer’s attention by the manipulation of formal features such as visual complexity, movement, cuts, pans, zooms and sound effects. Once the viewer’s attention has been captured, comprehension and retention are assumed to follow automatically without any special incentive to do so. P58
- Viewers monitor the presentation for cues that may indicate the presence of interesting content by listening to the audio and through peripheral vision or occasional glances at the screen. P59
- (Levin Anglin and Carney) They distinguished among five functions of pictures decoration (text irrelevant), representation (showing actors and objects to reinforce the narrative), organization (summarizing distinctive features or procedures), interpretation (clarify abstract concepts), and transformation (creating a memorable mnemonic). P66
- One often noted general function of illustrations and diagrams is that they provide an alternative source of complementary information to that given text. P67
- Individual differences: The literature on learning from static graphics and text offers a somewhat better view of the role of individual differences than does the more limited literature with video. P71
- Audio may be sufficient for those knowledgeable of a domain, but visual symbol systems supply important situational information for those less knowledgeable. P72
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