The way irrelevant dimensions are processed depends on what they overlap with: the case of Stroop- and Simon-like stimuli.

According to the dimensional-overlap model (Kornblum, 1992), irrelevant dimensions that overlap with a stimulus dimension (e.g., Stroop-type stimuli) are processed by a different stage than those that overlap with the response (e.g., Simon-type stimuli). We show that the effects of these two types of overlap are additive, thus supporting the model's hypothesis. We also show that the time course of facilitation and interference is different for these two types of overlap.