The Magical Number Seven Plus or Minus Two

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. Full text (PDF)

One of the most cited papers in cognitive psychology. George Miller, a Harvard psychologist, demonstrated that human short-term memory can hold approximately seven items (plus or minus two) at any given time. Miller called these items “chunks”: units of information grouped by familiarity or pattern.

For organizational design, this sets a hard limit: a team of 7 can maintain the internal relationships needed for effective collaboration, but beyond 9 or 10 members the cognitive demand of tracking who does what begins to exceed capacity. Miller’s research underpins later work on cognitive load (Sweller, 1988) and social group size (Dunbar, 1992).