CDLA · Module 2 — Learning science for digital media

Cut the extra — coherence and redundancy

Strip material that does not serve the objective. Do not narrate the same sentences you already printed.

About 18 min

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What this lesson covers

  1. 01

    Two ways we overfill the channel

    Coherence (median d = 0.70): eliminate extraneous material. Redundancy (median d = 0.87): do not add on-screen text to narrated graphics. Both protect working memory. “More explanation” is not automatically more learning.

  2. 02

    Captions are not the same as redundant text

    WCAG requires captions for prerecorded video with audio. That is an access requirement, not a violation of the redundancy principle. The research comparison is adding the same words as on-screen text to a narrated graphic for learners who can already hear it. Offer captions as a user-controlled track.

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