Do flexibility and stability trade off? Manipulating the proportion of switch and bivalent trials in the same blocks

Cognitive flexibility has been widely investigated using the task switching paradigm. In this context, it is common to observe that switching between tasks comes with a performance cost compared to repeating the same task. The resulting switch cost is therefore taken as a measure of cognitive flexibility. At the same time, performance costs are also observed when comparing performance in bivalent congruent trials compared to univalent trials, indicating that stimuli are capable of eliciting conflict at the task level. The resulting valency effect will be our measure of cognitive stability. Importantly, previous studies have reported that both the switch cost decreases in blocks where switches are frequent, and that the valency effect decreases in blocks where bivalent trials are frequent. These findings suggest that participants can upregulate the control mechanisms allowing for both flexibility and stability depending on the circumstances. In this regard, theories proposing that flexibility necessarily trades off with stability predict that increased flexibility should come with the cost of increased stimulus-based task conflict. At the same time, they also predict that increasing stability should come with increased switch cost. In order to test this theory, the current study will investigate whether manipulating the proportion of switches affects the valency effect, and whether manipulating the proportion of bivalent trials affects the switch cost. If there is a trade-off between stability and flexibility, we should observe a larger valency effect in majority-switch blocks. At the same time, increasing the proportion of bivalent trials should increase the switch cost. The present experiment extends two other experiments pre-registered at: https://doi.org/10.23668/psycharchives.14614 and https://doi.org/10.23668/psycharchives.15558