Lawo, V. , Philipp, A. M. , Schuch, S. & Koch, I.
RWTH Aachen University
A robust finding is that performance impairments in task-switching conditions (mixed-task blocks) relative to single-task conditions are larger for old adults than for young adults. Previous studies have suggested that these increased “mixing costs” are due to deficits either in the preparation of the relevant task set or to deficits in the inhibition of competing task sets. The aim of our study is therefore to examine the role of task preparation and task inhibition in the age-related increase in mixing costs. In two experiments, using a task-cuing paradigm with three different tasks, we assessed task preparation by manipulating the cue-stimulus interval (CSI). Task inhibition was assessed by measuring n-2 task repetition costs (e.g., ABA vs. CBA task sequences), which are assumed to reflect persisting inhibition of abandoned task sets. In both experiments, we observed a smaller preparation benefit in old adults. In Experiment 1, we found larger mixing costs for old adults than for young adults. Additionally, we only found n-2 repetition costs in Experiment 2 using blocked CSIs. These costs were comparable in both age groups. Together, the data suggest that impaired task-switching performance in old age is primarily due to a deficit in task preparation.