Electrophysiological Evidence for Different Conflict Types in the Stroop Task

Cognitive control enables individuals to prioritize goal-relevant information while suppressing competing, irrelevant inputs. The Stroop task has long served as a key paradigm for studying conflict processing, yet research has often focused primarily on the mismatch between word meaning and ink color (information conflict) while overlooking the competition between the color naming task and the automatic tendency to read (task conflict), and it is unclear how independent these conflicts are. This study examined the temporal and neural dissociation between task and information conflict using event-related potentials (ERPs) in a low-control Stroop design optimized to elicit both conflict types. Across two experiments, participants named the ink color of congruent, incongruent, neutral-word, and non-word stimuli while EEG was recorded. Cluster-based permutation analyses revealed distinct electrophysiological signatures for the two conflict types. Task conflict was associated with early neural responses, including posterior positivity around 180ms and a robust centro-frontal positivity around 250ms. In contrast, information conflict elicited a later sustained posterior positivity peaking around 700–800ms. Critically, both the amplitudes of the 250ms and late posterior components uniquely predicted trial-level reaction time, indicating that both conflict types contribute to behavioral slowing. These findings were replicated in a second study, which equated stimulus frequency between the non-words and the other stimulus categories. Together, the results provide converging evidence for temporally and functionally distinct neural mechanisms underlying task and information conflict, supporting domain-specific accounts of cognitive control and clarifying the time course by which different conflict types influence behavior.