Task Conflict in Task Switching

Abstract

Task switching requires maintaining readiness to execute any task of a given set of tasks. However, when tasks switch, the readiness to execute the now-irrelevant task generates interference, as seen in the task rule incongruence effect. Overcoming such interference requires highly fine-tuned inhibition that impairs task readiness only minimally. In this talk, three forms of task conflicts will be delineated in the scenarios of shifting between two tasks, three tasks, and four tasks respectively. More importantly, this talk will highlight a new form of task conflict in the scenario of shifting among four tasks. In experiments involving two object classification tasks and two location classification tasks, we (with Nachshon Meiran) show that irrelevant task rules that generate response conflicts are inhibited. This Competitor Rule Suppression (CRS) is seen in response slowing in subsequent trials, when the competing rules become relevant. CRS is shown to operate on specific rules without affecting similar rules and to operate on the competing responses only when generated by the specific competing rule. Using Event Related Potentials, we show CRS to operate during the cue epoch, suggesting that it involves the rules rather than the responses. Implications for current formal theories of task switching are discussed.