Although it is widely believed that verbal items are coded in primary memory (PM) in an acoustic or articulatory fashion, there is some evidence to indicate that PM may be a flexible system using the most salient characteristics of stored items. The possibility that semantic-associative attributes could facilitate free recall from PM was explored with 85 undergraduates. Clusters of 6 words, related either acoustically or semantically, were placed in the middle or at the end of free recall lists. From Ss' recall scores, pure PM functions were calculated for acoustic, semantic, and control lists. It was found that while both acoustic and semantic similarity facilitated total recall, this facilitation was limited to secondary memory (SM). Recall from PM was poorer for semantic than for control words; it is suggested that Ss sometimes retrieved semantic clusters from SM, even though the clusters occupied terminal list positions. (18 ref.) (PsycINFO Database Record (c) 2006 APA, all rights reserved)