The interactive effects of listwide control, item-based control, and working memory capacity on Stroop performance.

Abstract

Hypothesized top-down and bottom-up mechanisms of control within conflict-rich environments were examined by presenting participants with a Stroop task in which specific words were usually presented in either congruent or incongruent colors. Incongruent colors were either frequently (high contingency) or infrequently (low contingency) paired with the word. These items were embedded within lists consisting of either 100% congruent or 100% incongruent filler items to create mostly congruent or mostly incongruent lists. Results indicated a significant item-specific congruency effect, which was largest for high contingency responses and within mostly congruent lists. In addition, a significant listwide congruency effect was obtained, and this interacted with working memory capacity (WMC). There were larger listwide congruency effects for low WMC individuals. Finally, the pattern of Stroop interference across lists for low WMC individuals was dependent upon the congruency of the preceding trial. These results support multiple forms of cognitive control, as well as contingency learning, as mechanisms underlying proportion congruence effects in Stroop and other conflict tasks. These findings are interpreted within Braver, Gray, and Burgess's (2007) dual mechanisms of control theory.

Questioning conflict adaptation: proportion congruent and Gratton effects reconsidered

“…In other words, temporal learning QUESTIONING CONFLICT ADAPTATION 15 represents a powerful confound that will contaminate list-level PC experiments and produce a list-level effect even for contingency-unbiased items. Indeed, forthcoming work by Schmidt (2012b) demonstrates the same effect of previous response times on the list-level PC effect in Hutchison's (2011) data. Thus, the list-level PC effect, like the ISPC effect, is explainable in terms of simple learning biases.…”

“…In most cases, evidence for list-level PC effects independent of ISPC effects was not found (e.g., Blais & Bunge, 2010). There are a few findings, however, that suggest a very small contribution of list-level PC might exist Bugg, McDaniel, Scullin, & Braver, 2011;Hutchison, 2011). For instance, Hutchison compared items of equal item PC that were mixed together with other context items that were either mostly congruent or mostly incongruent.…”

“…Confounds other than contingency learning biases might be present in list-level PC experiments such as those of Hutchison (2011) and .…”

The Parallel Episodic Processing (PEP) model: Dissociating contingency and conflict adaptation in the item-specific proportion congruent paradigm

“…A difference between these two conditions can only be attributable to contingency learning. Hutchison (2011) recently performed a similar test in verbal Stroop data, where a contingency learning contribution was also confirmed. 2 Experiment 1 also tested for a contribution of the item-level PC of the word (i.e., low/low vs. low/high).…”

“…Recent work has indicated that list-level proportion congruent effects are also observable (e.g., Hutchison, 2011). That is, after accounting for item-specific learning, participants are responsive to the proportion of congruent trials in the task as a whole.…”