The Effect Of Foreknowledge And RSI On Task Switching: An ERP Study

Task switching is an important paradigm of studying executive control, and it refers topeople often need to rapidly shift from one task to another when they perform various tasks.Generally, responses take longer to initiate on a switch trial than on a repetition trail, and theerror rate is often higher after a task switch. Despite switch cost is a well-known phenomenonin task switching, the source of switch cost has been in dispute.The event-related potentials (ERPs) of20participants (10males and10females) wererecorded to investigate the effects of foreknowledge and response-stimulus interval (RSI) ontask switching and the nature of switch cost by using the task switching paradigm. The resultsshowed that:(1) There had a switch cost in every exprimental condition, and the responsestake longer to initiate on a switch trial than on a repetition trail.(2) The foreknowledge andRSI both had a preparation effect, the reaction time was smaller with foreknowledge thanwith non-foreknowledge and with increased RSI, but the switch cost was no differencesignificantly between foreknowledge and non-foreknowledge or among different RSIs.(3)With the RSI increased, the difference of cognitive processes between repeation task andswitch task appeared earlier. In1000ms RSI condition, the amplitudes of P2, P300-like, andLPC (late positive component) in switch task were significantly smaller than in repletion task.But in600ms and300ms RSI conditions, only the amplitudes of LPC in switch task weresignificantly smaller than in repletion task.The overall findings suggest that the source of switch cost is task-set inertia rather thanswitch-specific reconfiguration. The task-set inertia resulted a process of switch task wasextended, and which of the processes was extended depended on RSI.