The Role of Working Memory Capacity in Cognitive Control by way of Conflict Monitoring Open Access
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Cognitive control is especially important when environmental demands are taxing to the cognitive system. Cognitive control is closely related to many cognitive processes, including working memory capacity (WMC). Individuals with higher scores on working memory (WM) span tasks tend to exhibit better performance than low WM span individuals, especially in tasks that require the execution of top-down cognitive control. Therefore, the relationship between WMC and cognitive control is well-established, but how exactly they are related has yet to be elucidated. I conducted three experiments to test the hypothesis that WMC contributes to cognitive control via conflict monitoring, the mechanism that triggers the need for increased control. In Experiment 1, I employed a basic Simon paradigm, with two stimuli (green and red) and two responses (left key and right key). The trial-to-trial conflict adaptation ratio (CAR) increased as WMC increased. In Experiment 2, I altered the proportion of congruent trials (80%, 20%) per block, and found that WMC differences emerged in the sustained CAR (a measure of conflict adaptation across blocks). In Experiment 3, I included an equal proportion of congruent and incongruent trials in each block to examine the effects of feature binding and how these might interact with WMC. I found that an increase in WMC is correlated with a decrease in the Simon effect, but feature integration effects do not differ as a function of WMC. In combination, these findings suggest that the relationship between WMC and cognitive control can be explained by individual differences in conflict monitoring.