Tracking eye movements to localize Stroop interference in naming: word planning versus articulatory buffering.

Investigators have found no agreement on the functional locus of Stroop interference in vocal naming. Whereas it has long been assumed that the interference arises during spoken word planning, more recently some investigators have revived an account from the 1960s and 1970s holding that the interference occurs in an articulatory buffer after word planning. Here, 2 color-word Stroop experiments are reported that tested between these accounts using eye tracking. Previous research has indicated that the shifting of eye gaze from a stimulus to another occurs before the articulatory buffer is reached in spoken word planning. In the present experiments, participants were presented with color-word Stroop stimuli and left- or right-pointing arrows on different sides of a computer screen. They named the color attribute and shifted their gaze to the arrow to manually indicate its direction. If Stroop interference arises in the articulatory buffer, the interference should be present in the color-naming latencies but not in the gaze shift and manual response latencies. Contrary to these predictions, Stroop interference was present in all 3 behavioral measures. These results indicate that Stroop interference arises during spoken word planning rather than in articulatory buffering.