Mixing costs and switch costs when switching stimulus dimensions in serial predictions.

Mixing costs and switch costs are two markers for the costs that arise in multitasking situations. To further explore mixing costs and switch costs, we used a serial prediction task in which subjects switched between stimulus dimensions (i.e., color, form, and position). Using this task, we demonstrate that both mixing costs and switch costs are influenced by task conflict and the resolution of interference. Here, we show that both mixing costs and switch costs are affected by a local factor, namely the necessity to resolve interference in the current trial in mixed blocks. However, whereas mixing costs can be sufficiently explained by interference resolution in the current trial, switch costs are also affected by carry-over effects from the preceding trial. As regards these carry-over effects, the present paradigm enabled us to demonstrate the influence of both persisting activation and persisting inhibition on the performance in switch trials.