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Redundancy Principle

Redundancy Principle 1: Do Not Add On-Screen Text to Narrated Graphics

Extraneous processing –
Two visuals compete – look at graphic at same time look at visual text
Two processes compete – Compare two texts – process comparison of visual text with audio text
– Comprehend graphic – processing of the graphic with text explanation

Psychological Reasons for Redundancy Principle:
Learning styles hypothesis – different learning styles, visual versus auditory
– provide learners with both (visual text and audio narrated text)
–  learners can then choose which works for them
Information acquisition theory – learner receives information, instructor presents it
– three ways to receive information better than two
– pictures (illustration), spoken words (narration), written words (visual text)

Authors criticism of information acquisition theory:
1) assumes learn by adding information to memory
2) lack research evidence to support learning styles application in instruction
(visual learners learn better with visuals in instruction and
auditory learners learn better with audio in instruction)

Authors version how people learn (evidence supported):
1) separate channels for processing visual and auditory material
2) each channel has limited processing at one time
3) learners actively attempt build visual & auditory models of material & connections between them

Cognitive theory of multimedia
1) Overload visual channel – both visual graphic and visual text – shared processing
Cognitive overload – if presentation fast & learners unfamiliar with material
– selection and organization of material into mental models not complete
2) Extraneous cognitive processing – compare printed and spoken words
– processing spent reconciling text instead processing material

Evidence for Omitting Redundant On-Screen Text:
Multiple studies conducted – non-redundant (graphic and narration) group performed better than
redundant (graphic, narration and visual text) group
Boundary conditions – lesson fast-paced, words familiar, a lot words on screen
– system-controlled instruction (learner not control the pace)
So, as the authors state in their overall point, “in some cases, less is more.”

Redundancy Principle 2: Consider Adding On-Screen Text to Narration in Special Situations
Special situations – when not overload learner’s visual channel
May add visual text to narration when:
1) No pictorial presentation (no animation, video, photos, graphics, illustrations, etc.)
2) Redundancy is sequential or presentation pace is slow
3) Verbal text likely difficult for learner to comprehend (foreign language, long complex wording)
4) Few key words next to graphic

Psychological Reasons for Exceptions to the Redundancy Principle:
Major exceptions occur when: on-screen text not add to or diminishes learner’s processing
Example – bullets of objectives shown on screen – narration of intro to objectives in complete sentences
– visual channel not overloaded with graphic and words
– key words next to corresponding part of graphic – guides learner attention  (“signaling”)
– slow pace lesson presentation or learner control pace – learner has time to process

Evidence for Including Redundant On-Screen Text:
Studies that supported redundant text:
– there were no graphics on the screen – visual system not overloaded
–  short, sequential narration – see, hear text – then animation presented alone
– this unusual situation – not likely to be common in e-learning
– few key words next to corresponding part of illustration