The Magic Rule of 7 – Moronic Myth or Useful Rule of Thumb?

A reader supplied some links which contradict a portion of the BrainStormWFO sales page:

From the presentation: “Note that BrainStormWFO “auto-hoists”. This means that you are always focused on just one layer of the outline. This helps your brain relax, since you can only think about 7 items simultaneously anyway.”
I don’t intend to elaborate on this discussion, or this specific topic, I am just posting the links below for reference:
http://www.knosof.co.uk/cbook/misart.pdf
http://members.shaw.ca/philip.sharman/myth.html
http://www.edwardtufte.com/bboard/q-and-a-fetch-msg?msg_id=0000U6&topic_id=1
http://en.wikipedia.org/wiki/The_Magical_Number_Seven,_Plus_or_Minus_Two

My reply (to the links, not to the reader, whose opinions it doesn’t represent):

I understand that the topic of cognition is quite complex, and I am not making any claims about structuring lists, writing longtext documents or designing layouts.

I am saying that simultaneous comprehension of the interconnections between all child entries of an outline’s parent entry is limited to about 7 brief items, or less.

This is a general rule; obviously there are places where you would make exceptions.

The main fallacy of the misapplications dissected in the articles linked to is that most situations do not require simultaneous apprehension. It is perfectly acceptable to scan through a document serially, rather than attempting to comprehend its entirety at once. However, when rapidly structuring an outline, we need to immediately comprehend the entirety of the “small picture” at each layer, so that the “big picture” can automatically build itself with minimal mental exertion.

I find that 7 is the practical limit for this, and often I prefer 6 or 5.

The rule of 7 does refer to an experimentally verified limit of human mental capacity; it is just that cognition in practical situations has many ways of getting around this limitation, so trying to apply a rule of 7 naively as a general rule for designing everything is quite stupid.

I am not just talking about short term memory, the capacity to store and recall, but also the capacity to comprehend as an interconnected whole. The visuo-spatial analogue would be thinking of how seven moving parts interact in an engineering design.

Furthermore, the last link claims the number is even lower, 3 or 4. Perhaps this is true, but that is irrelevant since we do not have to remember by brute force when constructing an outline in BrainStormWFO; the text is remembered for us on the screen. We need only comprehend the interrelationships, i.e. ensure our categories are properly divided.

I think 3 or 4 is too simplistic for most people; 5 or 6 is where I’m most comfortable.

~JB