Chunking: how grouping helps you remember more

A chunk is a set of items bound together by meaning or familiarity. The digits 1, 9, 8 and 4 are four items to hold; as a year they become one. Phone numbers are split into groups for the same reason.

In 1973, Chase and Simon showed chess positions briefly to players of different strengths. Experts reconstructed real game positions far more accurately than novices. When pieces were placed randomly, much of that advantage disappeared.

Their interpretation was that experts perceive familiar patterns as single chunks. Their advantage came from knowledge of the game rather than a larger memory in general.

Ericsson, Chase and Faloon trained a student, known as SF, on digit span for more than 200 hours. His span rose from about seven digits to almost 80. He did it by recoding groups of digits as running times, drawing on his knowledge as a runner.

His span for letters stayed around six. The skill he built was specific to digits and to his own coding system.

In Signal Sequence and the Corsi test, split a long sequence into groups of two or three and rehearse the groups. In Object Archive, see the objects as a shape or a small scene. In The Briefing, link the person, place and object into one picture.

1. Miller, G. A. (1956). The magical number seven, plus or minus two: Some limits on our capacity for processing information. Psychological Review, 63(2), 81–97. doi:10.1037/h0043158
2. Chase, W. G., & Simon, H. A. (1973). Perception in chess. Cognitive Psychology, 4(1), 55–81. doi:10.1016/0010-0285(73)90004-2
3. Ericsson, K. A., Chase, W. G., & Faloon, S. (1980). Acquisition of a memory skill. Science, 208(4448), 1181–1182. doi:10.1126/science.7375930
4. Gobet, F., Lane, P. C. R., Croker, S., Cheng, P. C.-H., Jones, G., Oliver, I., & Pine, J. M. (2001). Chunking mechanisms in human learning. Trends in Cognitive Sciences, 5(6), 236–243. doi:10.1016/S1364-6613(00)01662-4

These notes summarise published research for general readers. They are not medical advice.

Keep reading