Abstract
In daily life, we are commonly faced with multiple objects that compete for selection. For example, crossing the street requires shifting attention between traffic signals, oncoming cars, other pedestrians, etc. While selection can be driven by behavioral goals, physically salient stimuli, such as flashing lights or bright road signs, often capture attention as well. Perceptual research demonstrates that highly salient distractors strongly capture attention and are more detrimental to behavior than less salient distractors. Contrary to this claim, however, our lab recently demonstrated that while this is the case for perception, the opposite pattern is observed for action: highly salient singleton distractors interfered less with target selection than weak ones (Moher, Anderson & Song, 2015). The authors concluded that distinct salience-driven suppression mechanisms exist for perception and goal-directed action. Here, we use fMRI to identify brain regions involved in this disparity. Our results demonstrate that clusters bordering the Anterior Cingulate Cortex (ACC) and medial frontal gyrus (MFG)—areas both previously implicated in conflict monitoring and task goal maintenance—were more active for less salient distractors during a perception task. Importantly, however, this pattern was reversed when participants performed goal-directed reaches toward the target: highly salient distractors led to increased ACC and MFG activation compared to less salient distractors. Research indicates that increased activity within these regions is associated with resolving conflict throughout goal-directed tasks. Accordingly, we offer the hypothesis that when goal-directed action is not required, less salient distractors are suppressed more effectively as indicated by faster reaction times and a higher BOLD signal. In contrast, highly salient distractors trigger suppression during goal-directed action, resulting in more efficient target selection and increased AAC/MFG activation. These results suggest that the same or similar cortical regions underlie dissociable effects of salience depending on action requirements.
Meeting abstract presented at VSS 2016