Age differences in voluntary task switching.

Task choice processes in older (60+ years) and younger (18-30 years) adults were compared using a voluntary task switching procedure (Arrington & Logan, 2004). To assess age-related differences in task representation maintenance, preparation times were varied across a large range of response-to-stimulus intervals (100, 500, 1,000, and 5,000 ms) and the environmental influence on task selection was varied by repeating or changing stimuli from trial to trial. Older adults switched less frequently than younger adults and this effect was the same at each RSI. Younger adults were more likely to switch tasks when the stimulus changed than when it repeated suggesting that they used a different process to determine task choices, either endogenous task selection or environmentally supported task repetitions. Older adults' task selection was unaffected by stimulus repetitions indicating that they were less flexible with the processing they used to guide task selection. These findings are consistent with previous observations of age-related increases in goal shielding, but not with age-related deficits in task goal maintenance. Robust age differences in switch costs were observed across RSIs suggesting that task reconfiguration processes are different following endogenous than exogenous task selection.