Chunking is one way to reduce cognitive information. Cherry defines it as ‘the process of taking individual units of information and grouping them into larger units’ in the field of psychology. Therefore, in the discussion of design and visual communication, this means to lighten the amount of information by grouping.
According to Errey, Ginns and Pitts (2006, p. 3), The memory can typically hold 7±2 items for rehearsal, and it will rapidly decay if nothing special done to keep quality. Instead of storing information in ‘bytes’ as in computers, it is stored in chunks of information. For example, it is popular to combine phone numbers not the list of all numbers but into chunks. Consider remembering the phone number 98328903 as opposed to 9 8 3 2 8 9 0 3. The one which is chunked is much easy to recognize that the latter. The chunks of information can vary from simple characters and numerals to more complex abstracts and images. The working memory can be expanded by abstracting qualities from the basic information and store the abstraction instead. Also, Chunking does not have to be based upon any logic within the elements of the material. However, if there is an underlying meaning/logic that can be identified, it is much easier to be recognized. In general, the more order that can be imposed on the raw data the better the chunking.
Cherry, K. What Is Chunking? Retrieved from http://psychology.about.com/od/cindex/g/chunking.htm
Errey, C., Gins, P., & Pitts, C. (2006). Cognitive load theory and user interface design: making software easy to use. Retrieved from http://www.ptg-global.com/PDFArticles/Cognitive%20load%20theory%20and%20user%20interface%20design%20Part%201%20v1.0.pdf