The Magical Number Seven, Plus or Minus Two (1955)

Modern consensus is that 4 is the real magic number. Humans can store only four chunks in short-term memory tasks.

For working memory and visual memory the number 4 pops up again and again.

When you are holding 5-9 things in memory you can't 'work with them' effectively. You might be chunking objects together or alternating very fast. Verbal memory can be tricky that way. (computer analogy: 4 is number or registers, 3-5 other objects may be stored in L1 cache).

Good starting point: Visual short term memory http://www.scholarpedia.org/article/Visual_short_term_memory

[1]: Cowan, N. (2001). The magical number 4 in short-term memory: A reconsideration of mental storage capacity. Behavioral and Brain Sciences, 24, 87-185. doi:10.1017/S0140525X01003922

[2]: Cowan, N., Elliott, E. M., Saults, J. S., Morey, C. C., Mattox, S., Ismajatulina, A., et al. (2005). On the capacity of attention: Its estimation and its role in working memory and cognitive aptitudes. Cognitive Psychology, 51, 42-100. doi: 10.1016/j.cogpsych.2004.12.001

[3]: The Magic Number 4 ± 0: A New Look at Visual Numerosity Judgements (1976) doi: 10.1068/p050327

[4]: The Magical Mystery Four: How is Working Memory Capacity Limited, and Why? (2010) doi: 10.1177/0963721409359277

I don't want to start a religious war, but can't we all just agree that eight is the ideal magical number, thanks to its voluptuous roundedness and power-of-two-ness?

Behold eight's symmetrical beauty: 8

Seven is just so odd, gangling, unbalanced, and awkward in comparison, like it's just about to fall over: 7

Fantastic, classic paper. Well worth the 20(?) minutes of attention it requires. Learning, memory, information theory...

im in the minus two camp

Tiny threads from 2015: https://news.ycombinator.com/item?id=9700016,

2014: https://news.ycombinator.com/item?id=8516542,

and 2010: https://news.ycombinator.com/item?id=1882628

Related from 2009: https://news.ycombinator.com/item?id=808039

Url changed from https://en.wikipedia.org/wiki/The_Magical_Number_Seven,_Plus... to the paper.