The effects of age and task domain on dual task performance: A meta-analysis

Recent research has argued against a general dual-tasking impairment in older adults, and suggests that task domain may be an important moderator variable (e.g. Riby, Perfect & Stollery, 2003). Here, meta-analyses were conducted on the results of studies between 1981 and 2003 to examine the conditions where older adults are impaired. A strong overall effect size indicated a clear age-related dual tasking impairment. However, this effect size was not representative of all the individual studies reported. Consequently, an analysis of variance analogue (Hedges & Olkin, 1985) was used to investigate potential moderators responsible for the variability in the effect sizes across studies. These secondary analyses included a comparision of dependant measure used (reaction time versus accuracy), whether baseline differences in performance had been controlled for and importantly the task domain. The key finding found task domain to be the crucial mediator, and those tasks with a substantial central processing component (e.g. episodic memory tasks) or motor component (e.g. tracking tasks) show greater age differences in dual tasking compared to those tasks that are data driven or rely on relatively automatic processing (e.g. simple perceptual or implicit memory tasks).