Redundancy Principle: Should You Duplicate Narrated Text On-Screen?

Do your e-learning courses include on-screen text with identical audio narration? If so, you’re definitely not alone. In fact, I’ll bet virtually everyone has taken, or created, a course like that at some point. However, just because it's a common practice doesn't necessarily mean it’s a good practice.

A number of studies have shown that learning is depressed by an average of 79% when a graphic is explained by both on-screen text and a duplicative audio narration. [1]

Redundancy Principle for Multimedia Design

Why? Learners can only process one thing visually at a time. If they’re reading the text, they can’t look at the graphics simultaneously. However, presenting the text as audio narration lets learners process it with their ears, and frees their eyes to focus on the graphic being explained.

Some designers might be tempted to include the redundant on-screen text as a way to accommodate both auditory and visual learning styles. There isn’t any evidence to show it helps boost learning, so it's not likely to be a good investment of your time and resources.

Does this mean you should never use on-screen text? Not at all. The redundancy principle is only relevant when the text explains a graphic. When there's no other visual content on the screen, research suggests that learning improves when you present the words as text and narration.

Here are a few other factors that may sway you toward displaying the text on-screen:

  • Cost: If you can’t record your own narration and you can’t afford to outsource it.
  • Technical constraints: If your audience includes learners who are viewing your course on devices without audio capability.
  • Non-native language: If your audience includes learners who would have trouble processing the spoken words.
  • Instructions: If you have any practice elements or exercises that might require your learners to refer back to the instructions.

Check out Tom’s demo demonstrating a variety of designs for the same content to see which one you think is the most effective.

Narration with redundant text

Redundant Narration and Text

Visual Design and narration without redundant text

Visual Design With No Text Narration Redundancy

While there is rarely a foolproof recipe for designing e-learning and other multimedia projects, you’ll definitely make better decisions if you know the basic design principles for how people learn. If you’re looking for a great place to start, check out, “E-learning and the Science of Instruction” by Ruth Clark and Richard Mayer.


1. Clark, R. C., and R. E. Mayer. E-Learning and the Science of Instruction, 2nd edition (San Francisco: Pfeiffer, 2007).

2. Mayer, R. E., “Introduction to Multimedia Learning,” in R. E. Mayer, ed. The Cambridge Handbook of Multimedia Learning(New York: Cambridge University Press, 2005).

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Bruce Graham
Mike Taylor

Hey Bruce! Yes, discussion is good. Ultimately negotiating with some clients may not be tied to what is best for learning. (That's a whole different discussion unto itself!) One thing you could do if they insist on designing to account for various learning styles is send them over to collect on Wil Thalheimer's Learning Styles Challenge. He's offering $1,000 to anyone can demonstrate that utilizing learning styles improves learning outcomes. It's been a lot of years and nobody has collected yet. Although the research is a few years old, I think the findings are still valid. I don' t think that human brains evolve quite that quickly. If you dig into the details a bit, especially the part about d... Expand

Erika P
John Lamble
Matthew Bibby
Andy Parker
Peter Rushton
Bryan Tregunna

The main reason I recommend NOT repeating text in the audio is that most of us read quicker than we speak. This means that for any text more than just a few words, the learner will be out of synch with the narrator - resulting in them neither understanding what they are reading nor listening to what they are hearing. Alternatively, the learner slows their natural reading speed to match the narration, which results in frustration. While I like to use audio, I find it creates problems which I feel outweigh its value. Ideally, narration should to be professionally produced - in a studio with a voiceover actor. However, budget or other constraints may not allow for this. A reasonable quality can be obtained with modern equipment, but this cannot compensate for the quality of the narrator - ... Expand

Lance  Blair

I'm a voice over talent, and I completely agree with what you say about reading in sync with the narrator. Good voice over falls in the range of 130-150 words per minute. I just finished a project with 250 slides that opens with "This tutorial is approximately 30 minutes long." Not with voice over! There is also the question of whether the audience is international, and speaking English as a second language. Clarity of diction and easy-to-follow pacing is essential, while still sounding engaging. I come from a video production background, and I identify with what you say about script revisions. I'm always on call for pickups and the first ten sentences of revisions are no extra charge. It's hard to get talent back if they do lots of commercial/radio/tv work. Choose a talent that specialize... Expand

Russell Duhon

I'm confused by the 79% claim of improvement on audio only vs audio plus redundant on-screen text; it seems to be a reference to this line in the cited source, except the line says basically the opposite: "In this situation, learners who received redundant on-screen text and spoken text generated an average of 79 percent more correct answers on a problem-solving test than learners who received only spoken text (Moreno & Mayer, 2002a)." The situation they're describing with the 79% improvement is one where "the learner sees and hears a sentence, then views ten seconds of animation corresponding to it, then sees and hears the next sentence, then views ten seconds of corresponding animation, and so on" -- exactly the sort of text on screen being read situation this article claims is bad. ... Expand

Rachel McGregor
Brenden Carter
Bruce Graham
Benjamin Passons

Good points all, and I'm glad this threat was resurrected because I'm pretty passionate about this... There are so many variables to consider. What type of course is it? If I'm building a course about how to write Arabic script for a non-Arabic speaker I might decide to have audio and animation of the script being written playing simultaneously ("Aaaslam Ali-koom" as the script is drawn out from right-to-left, maybe along with the English equivalent). However, if I'm building a course about how to change timing belts in Volvos (bear with me, not a car guy here) instead of: Audio: The timing belt is located under the flux capacitor in the '78 Volvo On-Screen Text: The timing belt is located under the flux capacitor in the '78 Volvo On-Screen Animation: Timing Belt is circled/highl... Expand