Abstract
It is well known that visual objects belonging to the same perceptual category compete for category-specific, limited-capacity attentional resource. However, it remains to be seen how perceptually identical objects interact with each other during visual analyses. Two perceptually identical objects might compete with each other as much as two different objects of a category. Alternatively, they might cooperate to form a stable, veridical representation. These conflicting possibilities were tested with three behavioral experiments. Experiment 1 and 2 used a name-picture Stroop task. In each trial, participants categorized a famous target name into that of an actor or a sports player while ignoring a flanking famous face distractor, which could be either congruent (e.g., an actor's name and face) or incongruent (e.g., an actor's name and a player's face). In some trials, either the same face or an unknown face was added in the opposite side of the face distractor. As results, relative to a single distractor, Stroop interference was reduced by two different distractors ("dilution effect") while it was enhanced by two perceptually identical distractors ("redundancy effect"). Importantly, this redundancy effect disappeared when two faces were the same at the response level, but different at the perceptual level. These results were replicated with nonface objects in Experiment 3, which further showed that neither dilution nor redundancy effect was affected by the between- vs. within-hemisphere distractor presentations. Our findings indicate that both dilution and redundancy effects may be mediated by perceptual representations based on hemisphere-independent attentional resources. In addition, both effects here support the hypothesis that Stroop interference arises through parallel attentional selection processes, rather than the deployment of a single attentional focus.
Meeting abstract presented at VSS 2012