Individual differences of working memory capacity in Stroop performance with reactive support and incremental proactive support of attentional control

Abstract

Working memory capacity (WMC) differences in Stroop task performance reflect differences in attentional control ability. However, support for preparing to control attention for each trial (proactive control support via low list congruency) or support for attentional control when a trial appears (reactive control via low item congruency) may additively or redundantly support the attentional control to minimize Stroop performance differences. Although previous literature has shown differences interact with list and item congruency effects in the Stroop task (Hutchison, 2011), some of the effects were marginal and the list congruency was manipulated between groups. This limits that ability to see how the need for reactive control support changes as proactive support changes. Therefore, the current study examined WMC difference in Stroop performance for mostly congruent and mostly incongruent items (which provide reactive support) as list congruency incrementally decreased (therefore incrementally increasing proactive list support). Results replicated Hutchison (2011) by showing that WMC differences are larger for mostly congruent items within mostly congruent lists, indicating that WMC is redundant with both proactive and reactive support. Further, our reaction time results suggested that those with lower WMC benefit from reactive support when proactive support is absent but benefit less when proactive support is present. In contrast, those with higher WMC have a consistent benefit of reactive support whether proactive support is present or not. Future studies should consider disentangling whether proactive and reactive control work separately or simultaneously interact with WMC.