Though it has huge implications on how presentations are made, I've never heard these ideas discussed apart from the work of John Sweller and his associates and the academic report,
Visualisation and Instructional Design. http://www.cmu.edu/teaching/trynew/sweller-visualinstructionaldesign.pdf
When it comes to preparing material for a speech or presentation, including the visual aids you use, the above variables are a huge issue.
On one end of the scale, are, say, four elements, A and B and C and D. These four factors are the key points of your presentation.
On the "low" end of the scale, each item can be discussed and learned independently and apart from the others elements, , , or low in interactivity with one another. They can be presented in serial or sequence, as completely different topics.
At the "high" end of the scale, each different element is very dependant on the other elements you are presenting or high in interactivity with one another. Necessarily, they must be learned in conjunction with one another.
The latter leads to what scientist call, cognitive overload. And to the best of your ability, you should design material that eliminates as much of "it" as you can.
But, how is this done. I suggest five different approaches, , ,
1. "Dumb it Down." Those are someone else's words, not mine. While I strongly believe in presenting in as simple a form as possible, but I don't think you should eliminate any academic value or challenge from any topic.
So you can almost eliminate this point.
2. Back to Basics. People do need to know and understand the basics of anything, , , and this is a very good way to approach any presentation. Building a speech around your A and B and C and D is not always a bad thing.
3. Study the Continuum. Look at your topic and see how much material is "very interactive." In today's complex world, there will be a lot of this interconnected information.
Then settle on a "middle of the road" approach. It might be is how does A relates to B. How A relates to C and finally how A relates to D. That's only three points to your whole presentation. At least, you'll have A covered pretty well.
4. Know Your Audience. This crazy scale might go completely across your audience. Some may want "milk" and others "high-cut meat."
5. The Fire in the Kitchen! There is always a temptation to cover the whole thing, including topics like "The B Picture," "The Three C's" and "The D Factors." My advice, DON'T. There will always be another day and another presentation. Most of the time, "less is more."
If you do choose to tackle the "whole enchilada," be sure to give your audience a lot of help with well-thought-out handouts, or visual aids or mnemonic tools, etc. or all of the above.