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Working memory: Seven Plus-Minus Two

1 October 2019

Elad Piran

"The Magical Number Seven, Plus or Minus Two: Some Limits on Our Capacity for Processing Information"[1] is one of the most highly cited papers in psychology.[2][3][4] It was published in 1956 in Psychological Review by the cognitive psychologist George A. Miller of Harvard University's Department of Psychology. It is often interpreted to argue that the number of objects an average human can hold in short-term memory is 7 ± 2. This has occasionally been referred to as Miller's law.[5][6][7]

The paragraph cited above is the opening paragraph of the Wikipedia entry discussing "The Magical Number Seven, Plus or Minus Two". To sum it up, Miller's 1956 seminal paper describes the limits of the human working memory. Our short term memory can process only a few items at any given moment. Miller even goes as far as stating a specific number: 7 ± 2. Miller argues that people can hardly remember more than 9 items recently learned. Actually, new studies have come up with even smaller numbers… obviously, this rule has its exceptions. Furthermore, the processed items may be item groups rather than individual items.

What does our limited working memory have to do with Knowledge Management?

When constructing knowledge items, we must consider the limitations of our working memory. This knowledge should affect how we construct lists, menus, catalogues and landing pages.

Here are some examples of how this knowledge can be implemented.

  • Collecting items and grouping them by category/family to reduce list length

  • Store similar items under multiple categories

  • Construct decision trees and navigation menus comprised of branches that do not exceed the 7 ± 2 rule

  • Planning the number of subjects/buttons on each internet page



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