The effect of aging on dual-task performance: A meta-analysis of studies between 1981 and 1997

Aside from meta-analysis of effect sizes and meta-regression of young-old RTs, a different meta-regression was performed, where dual-task cost was modeled by the regression relating the RTs for the dual to the RTs for the single task. These functions were compared between the young and the old. The data were extracted from 25 studies published between 1981 and 1997. The effect-size analysis showed a significant effect, which was influenced by whether two tasks shared the same internal codes. The meta-regression analysis indicated that dual-task cost occurred at the stage of central processing but the elderly were not more prone to such a cost than the young. One way of reconciling the discrepancies among the analyses is offered. (C) 2000 Academic Press.