Cognitive overload and OPTIONAL content

Jan 29, 2014

I'm working my way through E-Learning and the Science of Instruction by Clark and Mayer. The section I'm reading now discusses the coherence principal, which is basically KISS. Any information that doesn't directly contribute to the learning objectives should be removed because it doesn't increase the learner's retention rate and in many cases impedes retention.

Good stuff, makes sense, I've been saying that for years. It has frequently come up where my SME wants to include a lot of additional information and I've talked them down from that cliff by suggesting that information be offered as optional (meaning, on the website, or accessed through a button or the resources menu, what have you). For example, in one thing I'm working on, there are video testimonials that the learner could view if they wanted, but they are optional.

Anyone familiar with research that goes into whether optional material harms retention? My gut after reading this far into the book says yes, because it would still be taking up short and long term memory for the learner. But the studies have also found that higher-level learners (ie, learners who already have a decent grasp of the material) can easier deal with extra information than lower-level learners, and my guess is that it's primarily the higher-level learners who would access this optional information.

17 Replies
Patryce Smith

Hi Katie,
I see where the video testimonials are optional. Is the information provided by these video tutorials additional extraneous content or does it reinforce the necessary information presented? I think the answer to that question will help to determine if the viewing of the optional material will harm retention.

- Patryce

Nick n/a


''But the studies have also found that higher-level learners (ie, learners who already have a decent grasp of the material) can easier deal with extra information than lower-level learners''

What studies are these?

Edit: I'm also looking at cognitive load at the moment. And it's always good to have more material at hand.


Rich Calcutt

Hi Katie - You should definitely keep the main content in the module as tight and focussed as you can to avoid the cognitive overload you mention. Remember that cognitive overload can happen as a result of using too many sensory 'channels' too - i.e. having graphics, words, narration, and interactivity all on the slide. 

In terms of optional material - I support it to an extent. If I'm a learner with existing knowledge of the material I might want to find out more info that's above and beyond the main course messages. In many cases I'd just include links to external material, but I see no harm in including it in the course if you want. I think the worst thing would be if a learner wanted to find out more about the subject but couldn't find any additional resources. 

Good luck

Bruce Graham

I nearly always include optional material in sales courses.

A salesperson would need to know the high-level competitive position, target audiences/sweet-spots, potential market, risks etc.

They may not need to know at that point all the product specifications, history, market activity, prizes won by the product etc. however, (as Richard points out), they would need them at some point.

These may be in the course as References, or in the LMS - depending on client build and requirements.

Brent deMoville


I think it all depends on the nature of the optional content.  Humans are naturally wired to respond to and remember stories.  If your optional content is a story that supports the key facts in your main content then I think it will enhance retention of the material.  If the optional material is straying very far from the main content then I think it will be a distraction and add little value.

I develop in a corporate environment and our learners are so time constrained that for them it is "the facts and nothing but the facts."  When I have developed content for more of an elective learning environment I find the learners more willing and interested in the ability to dive deeper into some content when it is optional.

Mike Taylor

There has been some interesting research around how experts learn differently than novices. The one that comes to mind is DeGroot's experiments with chess players. There is some interesting  information here:

And this is a good site that has more details about that specific chess scenario:

Cary Glenn


Here is a study that supports what Katie is saying.

This is one of the weird and difficult parts of designing eLearning. The learners may be novices or experts, they may be interested in the subject or look at it as a waste of time. Yet we have to design learning that meets their needs. As a classroom instructor I can tailor information on the fly depending on the audience; this is much more difficult with eLearning.

I'm thinking one way to do this would be to have separate scenes that could provide more information or links so that people could explore the field to gather a greater depth of knowledge. It would also be possible to build a separate test for experts where they would have to research some of the information themselves.

Bruce Graham

If we are all really designing courses that have been designed, advertised/marketed so that there is a strong "What's in it for me", then all the content should be relevant for the learners whether optional or not.

I am not always a fan of "research material" - there are plenty of well-qualified types out there who can quote all the stats and reports, but would get thrown out of an eLearning contract because they do not understand the principles of good old business pragmatism and politics.

Being an instructional designer involves a lot of pruning - getting rid of the excess and creating something that suits your needs. You may need to have other courses to meet other needs, but "...on the fly" changes are not appropriate for this media, in my opinion.

Most times I find clients request optional content when they are really not sure what they are trying to achieve, and are attempting a "blunderbuss" approach, ("...we have GOT to be able to hit something with that, surely?") rather than following the approach of a trained sniper, (forget about everything else - agree on the target, control what you do, plan what you do, fire, job done).

Saying that, I have designed many courses that offer different routes for different information. If you make it overt, (our menu was a railway map with different routes for different levels of staff - see image below), you may find they will all do all sections anyway, just to see what the "senior management (red route)" or the "juniors (blue/brown route)" are being taught.

Katie Venit

Nicholas Ostheimer said:


''But the studies have also found that higher-level learners (ie, learners who already have a decent grasp of the material) can easier deal with extra information than lower-level learners''

What studies are these?

Edit: I'm also looking at cognitive load at the moment. And it's always good to have more material at hand.


Nicholas, Oh boy, there are so many quoted in that book I mentioned. It depends, also, on which aspect of elearning you're looking at. The book is basically a compilation of studies done on elearning. Without combing through the entire book, one I happened to see was Sanchez and Wiley, An examination of the seductive details effect in terms of working memory capacity, 2006.  There's so many scattered throughout the book, though.

Sharon Elin

I've enjoyed this discussion and it has given me much to think about!

As a high school teacher who is now an online course developer creating courses for teens,  the driving factors we emphasize are engagement, interest, and relevance -- because without these, the content doesn't matter to our rolling-eyed target audience. Comparatively, adult learners in a business setting are much different (... or are they)? It seems adults can force themselves to move through a course even if they're bored, because they know they "have" to do it and they have more patience from maturity.  Teenagers, though, are resistant to begin with and understandably want to connect the material they're learning with their real lives -- otherwise, they will simply press "Next" until the module ends.

Trimming all the extraneous fluff is a wise idea as far as eliminating distractions from the main points in a module, but as other designers have mentioned, stories, humor, and interactive "games" reach users (especially the teens we are designing for) and encourage them to connect with the material. This engagement factor opens their minds to the messages and prepares them to be receptive to learning.  It is a tricky skill to blend the concept of streamlining with the concept of winning interest and attention, but that is what I believe good designers must do. Too much of one or the other kills the desired effect.

I agree, then, that many courses are overloaded with noise and unnecessary information, but I believe there is a need for compromise, especially when the target audience is not a willing one. 

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