Andrew Rodriguez¹ (), Derrek T. Montalvo¹, Mark W. Becker¹; ¹Michigan State University

There is strong evidence suggesting that feature-based attention can facilitate the selection of relevant items by feature enhancement. More recently a number of prominent papers have claimed that the suppression of irrelevant features also facilitates the selection of relevant items, however this evidence is less complete and more controversial. Here we present two experiments that fail to find evidence for active suppression. In both, participants performed a dot filtering task where they ignored one set of colored dots (distractor suppression) to detect the number of changes in luminance in a different set of colored dots (feature enhancement). On a random 25% of trials, the filtering task was interrupted by a visual search task. Search arrays consisted of clock face consisting of 12 letters, six of which appeared in a single color and the other six appeared in six different colors. Consistent with feature enhancement, our results show fast RTs when the target letter appeared in the filter task’s attended color and slower RTs when half of the distractor letters appeared in the attended color. But we found no evidence for distractor suppression; neutral-colored targets were not detected more quickly when half the distractors matched the to-be-ignored color and RTs were not slower for targets that matched the ignore color than a neutral color. In Experiment 2, we altered the dot filtering task so that the to-be-ignored color remained constant while the to-be-attended color varied trial to trial. In addition, during the search task the attended color from the previous filter task never appeared as the target. These changes were done to reduce the benefits of target enhancement while maintaining the benefit created by suppression, thereby increasing the motivation to apply suppression. Nevertheless, our preliminary findings still show little evidence of effective active suppression.