K. Oberauer et al., Dissociating retention and access in working memory: An age-comparative study of mental arithmetic, MEM COGNIT, 29(1), 2001, pp. 18-33
In two experiments, young and older adults solved arithmetic chain tasks wi
th single-digit operands, with or without a concurrent memory load of three
or six digits. Variables in the arithmetic tasks had to be replaced by dig
its from the screen or from the memory set. A task-irrelevant concurrent lo
ad impaired neither speed nor accuracy of arithmetic in younger adults. In
Experiment 2, this was also true for older adults. A large decrease in arit
hmetic performance was observed, however, when variables in the arithmetic
task had to be substituted by digits from the memory list. Older adults had
specific problems with this condition in Experiment 1, where the substitut
ion involved two successive steps, but not in Experiment 2, where the subst
itution from memory could be done in a single step. The results are difficu
lt to reconcile with models assuming a common resource for storage and proc
essing. Rather, they are compatible with the hypothesis that a concurrent m
emory load interferes with a processing task only during the points of acce
ss to working memory. Further, even though access to working memory was fou
nd to be the critical source of concurrent-load interference, it was found
to be insensitive to the effects of adult aging.