Abstract
Different implication of control mechanisms in the random and regular shift of mental set. In this study we explore the differences when shifting between two different tasks in two conditions: when the shift is predictable and when it occurs at random. The residual cost is the part of cost for shifting tasks which remains after the operation of an anticipatory process of task-set reconfiguration (Rogers & Monsell, 1995). The residual cost is not significant when tasks shift at random for one second SOA condition. Besides, the so-called cost asymmetry, which supports the mental inertia hypothesis (Allport, Styles and Hsieh, 1994), is not obtained, either. However, when tasks shift predictably, both a significant residual cost and a cost asymmetry (in the direction predicted by the mental-inertia hypothesis) are found. We conclude that a control mechanism becomes activated in the random-shift condition, so reducing the mental inertia associated with the previous task set.
