Dc. Geary et al., SIMPLE AND COMPLEX MENTAL SUBTRACTION - STRATEGY CHOICE AND SPEED-OF-PROCESSING DIFFERENCES IN YOUNGER AND OLDER ADULTS, Psychology and aging, 8(2), 1993, pp. 242-256
Thirty-six younger adults (10 male, 26 female; ages 18 to 38 years) an
d 36 older adults (14 male, 22 female; ages 61 to 80 years) completed
simple and complex paper-and-pencil subtraction tests and solved a ser
ies of simple and complex computer-presented subtraction problems. For
the computer task, strategies and solution times were recorded on a t
rial-by-trial basis. Older Ss used a developmentally more mature mix o
f problem-solving strategies to solve both simple and complex subtract
ion problems. Analyses of component scores derived from the solution t
imes suggest that the older Ss are slower at number encoding and numbe
r production but faster at executing the borrow procedure. In contrast
, groups did not appear to differ in the speed of subtraction fact ret
rieval. Results from a computational simulation are consistent with th
e interpretation that older adults' advantage for strategy choices and
for the speed of executing the borrow procedure might result from mor
e practice solving subtraction problems.