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Title: Rehearsal-based strategies for updating verbal working memory
Author: Greaves, Martin Henry
ISNI:       0000 0001 3513 9975
Awarding Body: University of Hertfordshire
Current Institution: University of Hertfordshire
Date of Award: 2008
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The understanding of information encoding and retrieval processes in working memory is one of the fundamental problems of cognitive psychology. Information monitoring tasks, in which the current status of changing information is tracked, are claimed to require the use of updating processes in working memory. This thesis examines updating in the running ' memory span task (Pollack, Johnson, & Knaff, 1959), a task requiring the reporting of the most recent items from a continuous stream of spoken information. The aim is to better understand updating of working memory in terms of the processes that are employed during encoding and the memory structures associated with recall. Empirical data and ACT-R . cognitive models are used to compare one theory ~laiming that verbal information . is stored in the phonological loop, and updated via associated positional information under the control of a supervisory central executive (Morris & Jones, 1990), with a recency-based account, in which updating arises from storage of items in episodic memory (Ruiz, Elosua, & Lechuga, 2005). This research argues against a unitary account of updating. Examining the impact of a range of different rehearsal strategies on recall revealed significant improvements in running memory span when participants were trained to use active rehearsal strategies compared with recall following the passive encoding of items. Further increases in span were observed with increasing organisation in rehearsal. Six major strategies were identified by self-report, when varying presentation rate and memory load. These included shadowing of the current item, updating rehearsal of a list ofrecently presented items and rehearsing adhoc lists when memory load restricted the use o~task specific strategies. The key finding is that the selection ofrehearsal strategies depends systematically on task conditions. ACT-R models of encoding and retrieval supported empirical findings demonstrating that key rehearsal strategies were associated with complex patterns of recall, requiring encoding of items into both a phonological loop and episodic memory. These findings reveal a varied and diverse account of memory updating processes, based around the use of rehearsal strategies and the availability of working memory structures for tracking and updating of verbal working memory.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available