Reference
Nelson Cowan
The argument that the core limit on short-term memory is about four chunks rather than seven comes from his 2001 target article.
Cowan's The Magical Number 4 in Short-Term Memory gathered results from many kinds of task to argue for a central capacity limit averaging about four chunks, within a range of three to five. The contribution is as much about method as about the number: a limit counted in chunks can only be observed under conditions where rehearsal and long-term memory cannot bundle items into chunks of unknown size. He calls longer spans, which mix in those other sources, compound estimates.
The figure is often repeated as if it were settled. It is not. Whether visual working memory has any fixed item limit is still disputed, and Cowan's own work with Chen found about three chunks in verbal recall when rehearsal was prevented.
Referenced work
- The magical number 4 in short-term memory: A reconsideration of mental storage capacity (Behavioral and Brain Sciences, 2001) reference
- The Magical Mystery Four: How is working memory capacity limited, and why? (Current Directions in Psychological Science, 2010) reference
Elsewhere
Listed here because we name Nelson Cowan in our writing. We are not affiliated with them and this page is our summary, not theirs.