Working memory capacity is severely limited in adults (1–6) and infants (7–11), with both groups able to remember only about three separate items at once. One reason that adults are rarely conscious of this constraint is that we can hierarchically reorganize the to-be-remembered stimuli, thereby increasing the total number of items we can store. For example, the letter string PBSBBCCNN is much easier to recall after recognizing the three familiar television acronyms PBS, BBC, and CNN that comprise it.

For several decades this limited number was thought to be 7 +/- 2 (16). However, more recent analyses show that 7 +/-2 overestimates working memory capacity. ( Read more... )