Learned Switch Readiness Via Concurrent Activation of Task-Sets: Evidence from Task- Specificity and Memory Load

Cognitive flexibility increases when switch demands are high. In experiments involving task switching, repeated pairing of flexibility-demanding situations with specific contexts leads subjects to become more prepared to adapt to changing task demands in those contexts. Subsequent exposures to those contexts serve as cues for cognitive flexibility, resulting in learned switch readiness. One form of such learned switch readiness has been robustly demonstrated with a list-wide switch probability (LWSP) effect where switch costs are smaller in lists (i.e., a block of trials) with frequent switches than in lists with rare switches. According to a recent proposal, the LWSP effect is supported by a concurrent activation (CA) mechanism whereby the two task rules are kept available simultaneously in working memory (WM). We tested the hypothesis that the CA mechanism underlies the LWSP effect by examining two specific predictions: (1) the LWSP effect is limited to only the trained tasks, and (2) concurrent working memory load reduces the LWSP effect. We conducted 4 experiments, each aimed at one of these predictions. In Experiment 1, we replicated and extended previous findings that the LWSP manipulation modulates both performance (switch costs) and voluntary switch rates (VSR), indicating that learned switch readiness is generalizable so long as the task-sets remain the same. Results of Experiments 2 and 3 showed that novel tasks do not benefit from the CA of the two tasks, suggesting that the LWSP effect is task-specific. Experiment 4 showed that holding additional information in WM reduces the LWSP effect. Together, these findings suggest that CA is likely the mechanism underlying the learned switch readiness of the LWSP effect.