An Integrated Theory of List Memory

John R. Anderson
Dan Bothell
Christian Lebiere
Michael Matessa


The ACT-R theory (Anderson, 1993, 1998) is applied to the list memory paradigms of serial recall, recognition memory, free recall, and implicit memory. List memory performance in ACT-R is determined by the level of activation of declarative chunks which encode that items occur in the list. This level of activation is in turn determined by amount of rehearsal, delay, and associative fan from a list node. This theory accounts for accuracy and latency profiles in backward and forward serial recall, set size effects in the Sternberg paradigm, the mirror effect and length-strength effects in recognition memory, serial position and length-strength effects in free recall, and lexical priming in implicit memory paradigms. This wide variety of effects is predicted with minimal parameter variation. It is argued that the strength of the ACT-R theory is that it offers a completely specified processing architecture that serves to integrate many existing models in the literature.