We examined the effect of age on working memory with a reading span task (R
ST) together with other verbal span tasks. Sixty-two participants were divi
ded into three subgroups (young, middle-aged, and elderly). The RST perform
ances were significantly different among all the subgroups. To elucidate wh
ich component of the working memory system is affected by age, we performed
an analysis of covariance with the scores of simple and complex verbal spa
n tasks as covariates. From the results, we conclude that the difference of
the RST performance between the middle-aged and elderly groups reflects a
decline in the capacity of the phonological loop, and the difference betwee
n the young and middle-aged groups reflects malfunctioning of the central e
xecutive system.