Gs. Waters et D. Caplan, THE MEASUREMENT OF VERBAL WORKING-MEMORY CAPACITY AND ITS RELATION TOREADING-COMPREHENSION, The Quarterly journal of experimental psychology. A, Human experimental psychology, 49(1), 1996, pp. 51-79
Ninety-four subjects were tested on the Daneman and Carpenter (1980) r
eading span task, four versions of a related sentence span task in whi
ch reaction times and accuracy on sentence processing were measured al
ong with sentence-final word recall, two number generation tasks desig
ned to test working memory, digit span, and two shape-generation tasks
designed to measure visual-spatial working memory. Forty-four subject
s were retested on a subset of these measures at a 3-month interval. A
ll subjects were tested on standard vocabulary and reading tests. Corr
elational analyses showed better internal consistency and test-retest
reliability of the sentence span tasks than of the Daneman-Carpenter r
eading span task. Factor analysis showed no factor that could be relat
ed to a central verbal working memory; rotated factors suggested group
ings of tests into factors that correspond to digit-related tasks, spa
tial tasks, sentence processing in sentence span tasks, and recall in
sentence span tasks. Correlational analyses and regression analyses sh
owed that the sentence processing component of the sentence span tasks
was the best predictor of performance on the reading test, with a sma
ll independent contribution of the recall component. The results sugge
st that sentence span tasks are unreliable unless measurements are mad
e of both their sentence processing and recall components, and that th
e predictive value of these tasks for reading comprehension abilities
lies in the overlap of operations rather than in limitations in verbal
working memory that apply to both.