The bivalency effect in task switching: general and enduring.

The purpose of this study was to investigate the generality and temporal endurance of the bivalency effect in task switching. This effect refers to the slowing on univalent stimuli that occurs when bivalent stimuli appear occasionally. We used a paradigm involving predictable switches between 3 simple tasks, with bivalent stimuli occasionally occurring on one of the tasks. The generality of the bivalency effect was investigated by using different tasks and different types of bivalent stimuli, and the endurance of this effect was investigated across different intertrial intervals (ITIs) and across the univalent trials that followed trials with bivalent stimuli. In 3 experiments, the results showed a general, robust, and enduring bivalency effect for all ITI conditions. Although the effect declined across trials, it remained significant for about 4 trials following one with a bivalent stimulus. Our findings emphasise the importance of top-down processes in task-switching performance.