The role of visual stimuli in cross-modal Stroop interference

It has long been known that naming the color of a color word leads to what is known as the Stroop effect. In the traditional Stroop task, when compared with naming the color of a color-neutral stimulus (e.g., an X or color patch), the presence of an incongruent color word decreases performance (Stroop interference), and a congruent color word increases performance (Stroop facilitation). Research has also shown that auditory color words can impact the color naming performance of colored items in a similar way in a variation known as cross-modal Stroop. However, whether the item that is colored interacts with the auditory distracter to affect cross-modal Stroop interference is unclear. Research with the traditional, visual Stroop task has suggested that the amount of color the visual item displays and the semantic and phonetic components of the colored word can affect the magnitude of the resulting Stroop interference; as such, it is possible the same components could play a role in cross-modal Stroop interference. We conducted two experiments to examine the impact of the composition of the colored visual item on cross-modal Stroop interference. However, across two different experiments, three test versions, and numerous sets of trials, we were able to find only a small effect of the visual stimulus. This finding suggests that while the impact of the auditory stimuli is consistent and robust, the influence of nonword visual stimuli is quite small and unreliable and, while occasionally being statistically significant, it is not practically so.