Memory span and speed of processing: A developmental study
Abstract
The present study was aimed at determining the influence of speech rate and speed of information processing on memory span, and exploring how these factors could account for age-related improvements in memory span. The study compared predictions from the model of working memory proposed by Baddeley with an alternative view based on the role of processing speed in memory development. The study involved two groups of children, with mean ages 10 and 12 years respectively, and a group of adults, with a mean age of 20 years. Measures of memory span, speech rate, and speed of visual search were obtained from each subject. The words used as stimuli varied in length in that they contained 1, 2, or 3 syllables. For the memory span task, subjects recalled words in order from lists presented visually. For the speech rate task, subjects repeated pairs of words a specified number of times and were timed. In the visual search task, subjects looked for target letters in words presented on a video monitor. These tasks provided measures of span, speech rate, and visual search rate for words of three different lengths for each subject. Results showed that memory span, speech rate, and visual search rate decreased with increases in word length and improved with age. Memory span varied linearly as a function of both speech rate and search rate across differences in word length and age. Hierarchical regression analyses performed on both group means and on individual differences indicated that speech rate, search rate, and age were all significant influences on span. Each variable accounted for a part of the variance in span. Search rate accounted for some variance in span that was not explained by speech rate, and age accounted for some variance that was not explained by either speech rate or search rate. The results suggest that speech rate and speed of processing contribute to development in memory span but do not, either alone or in combination, account for all developmental improvement in span. The results are discussed in terms of Baddeley's model of working memory and problems with the model are pointed out.
Degree
Ph.D.
Advisors
Kail, Purdue University.
Subject Area
Developmental psychology|Psychology
Off-Campus Purdue Users:
To access this dissertation, please log in to our
proxy server.