The "memory cliff" beyond span in immediate recall.

Abstract

Immediate recall of sub-span, span length, and supra-span memoranda was tested in 27 normal nursing students. Random series of digits and consonant letters ranging from 5 to 20 items were presented at the rate of 1 per second. Maximum recall occurred with memoranda of approximately span length, with a sharp drop of recall as span was exceeded. Absolute recall of supra-span memoranda remained at a plateau after the initial drop. The use of a special scoring method and analysis of data by relating the results to each individual's span permitted an accurate representation of the drop in recall as span was exceeded and the constancy in recall with supra-span memoranda. It is concluded that for immediate ordered recall maximum information gain occurs for each individual at his span rather than at an arbitrary memorandum length This study indirectly supports the separation of immediate memory and storage mechanisms.