The effects of stimulus onset asynchrony on the item-specific proportion congruency effect in a picture-word stroop task

The item-specific proportion congruency (ISPC) effect is demonstrated by a larger Stroop effect for mostly congruent (MC) items compared to mostly incongruent (MI) items. In previous studies, we showed that the ISPC effect changed as a function of stimulus onset asynchrony (SOA). Specifically, the ISPC effect was observed for the -200 ms (word-first), and 0 ms (simultaneous) conditions, but disappeared in the +200 ms (color-first) condition. The aim of the current study was to conceptually replicate and extend these previous findings to a picture-word Stroop task. Results showed that the ISPC effect changed as a function of SOA, supporting our previous results. Specifically, the ISPC effect was observed for the -200 ms and 0 ms conditions, but not when the word came too late (+200 ms). Taken together, these results suggest that the ISPC effects observed with color-word and picture-word Stroop tasks might have similar underlying mechanisms