The distractor frequency effect: An overt naming ERPs study

We used the event-related potential (ERP) approach to track the time-course of the distractor frequency effect in the color-naming Stroop task, i.e. the longer naming latency when to-be-ignored words are low-frequency rather than high-frequency words. ERPs elicited by colored words were influenced by distractor frequency in 160-220 ms and 300-400 ms timewindows. In a Stroop variant of the color naming task, ERPs elicited by colored words were affected by color/word congruency in 300-400 ms and 500-600 ms time windows. Temporal and polarity features of distractor frequency and Stroop ERP responses suggest that the distractor frequency effect in the color-naming Stroop task is characterized by at least two temporally and functionally distinguishable ERP effects: one early effect that we interpret as reflecting the processing of the distractor words and one mid-latency effect reflecting suppression of the distractor word.