Distinguishing between inhibitory and episodic processing accounts of switch-cost asymmetries.

In two experiments, the authors investigate whether switch-cost asymmetries that are often observed in studies of task switching (e.g., Allport, Styles, & Hsieh, 1994) can be best explained by reference to an inhibitory mechanism or episodic memory principles. In Experiment 1, the authors replicated the basic finding, observing the highest switching costs when participants were required to perform an easier perceptual task after having just performed a more difficult conceptual judgment. The reverse task switch produced a significantly smaller switching cost. Experiment 2 revealed that the cost of switching from one difficult conceptual task to another is also higher than the cost of switching from one easy perceptual task to another. In combination, our results demonstrate that the cost of task switching depends mainly on the difficulty of the task participants are required to switch from, favouring an episodic processing account of this switch-cost asymmetry.