Interference Resolution in the Elderly: Evidence Suggestive of Differences in Strategy on Measures of Prepotent Inhibition and Dual Task Processing

ABSTRACT

The ability to effectively resolve interference was investigated in young and elderly participants using a test of inhibition and a dual task measure. The tasks stressed the ability to suppress prepotent responding, and balance primary and secondary task demands, respectively. Successful performance on both measures hinged on the ability to minimize the distraction generated between competing aspects of each task. Increasing demands resulted in performance decrements despite titration for individual differences in span size and generalized slowing. These were more pronounced on the hardest condition of each task, especially in older participants. Furthermore, the nature of the decrements suggested the use of different strategies between groups. It is argued that a fundamental source of the age-associated variability in cognition is due to compromised ability to effectively resolve interference, and cannot be sufficiently explained by memory span differences or generalized slowing.