Chunking

The account number on a credit card has sixteen digits, but they are grouped into sets of four. This allows us to read the number in easily grasped chunks, when transcribing it onto a form or web page. 

The psychologist George Miller showed that people could recall up to five words or seven digits immediately after hearing them. His paper entitled ‘The Magical Number Seven’ is much cited, although no longer the latest word on the topic. 

Chunked information is easier to use for several reasons: 

• it allows for the limitations of working memory, which struggles to cope with long strings of information (see Processing load).
• its graphic appearance makes information easier to skim read (see Strategic reading).
• the graphic arrangement of chunks on a page can communicate their relationship (see Gestalt principles).

Miller, G. (1956). ‘The magical number seven, plus or minus two: Some limits on our capacity for processing information’. Psychological Review, 63, 81-97.