Facilitation and interference effects in a Stroop-like task: evidence in favor of semantic processing of parafoveally-presented stimuli.

In this study we used a modified Stroop word-color task in which the target was a centrally fixated color frame and the distractor was an incompatible, compatible or non-color word. In Experiment 1 distractors were located either within (the inside condition) or outside the frame, at distances of 1.3 deg (near-outside condition) or 2 deg (far-outside condition). In Experiment 2 only the inside and the far conditions were used. The stimuli were on the screen for 150 msec (Experiment 1) or 50 msec (Experiment 2). A non-distractor condition was also included. In Experiment 1, incompatible distractors interfered with naming target colors, and this effect disappeared when the distractor was located far from the target. However, facilitation from compatible distractors was reliable in the farther location. These results were replicated in Experiment 2. The data suggest that (1) unattended items are processed semantically; (2) that facilitation and interference from words in color naming tasks can be caused by different mechanisms; and (3) that distractors are processed differently according to whether they are near or far from fixation.