Type of Document Master's Thesis Author Barrett, Natasha Ann Author's Email Address nbarrett78@yahoo.com URN etd-11272007-104111 Title ESTIMATING THE CAPACITY OF VISUAL SHORT-TERM MEMORY: A TRANSCRANIAL DOPPLER SONOGRAPHY STUDY Degree Master of Arts Department Psychology Advisory Committee
Advisor Name Title David A. Washburn Committee Chair Eric J. Vanman Committee Member Heather M. Kleider Committee Member Keywords
- short-term memory
- Visuospatial memory
- hemovelocity
- capacity
- transcranial Doppler (TCD)
Date of Defense 2007-09-06 Availability unrestricted Abstract Estimates of the capacity of visuospatial short-term memory (VSTM) have ranged from less than 1 item to 4 +/- 1 items. The purpose of the present study was to find the capacity of VSTM by looking at the contribution of the other working memory systems (phonological loop and central executive) and determine the factor that limits VSTM capacity (either number of objects or object complexity). In this study, the psychophysiological measure of cerebral blood flow velocity also was incorporated to determine whether changes in cerebral blood flow velocity were indicative of VSTM performance and capacity. Both performance measures and cerebral blood flow velocity indicate that capacity for random polygons is approximately one object. Complexity of the objects affected capacity, such that simple objects had higher capacities and lower cerebral blood flow velocity than complex objects. Other working memory systems were not found to have an effect on performance.Files
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