Conflict dynamically shapes the focus of visual attention

The ability to deal with conflict from processing incompatible sensory information is fundamental to
adaptive behaviors in humans and other primate species. It is generally known that conflict reduces the
speed and efficiency of sensory information and decision-making processes. One prominent theory posits
that such behavioral interference is due to an additional step required for individuals to focus their
attention on task-relevant sensory inputs while filtering out task-irrelevant distractors. Recent studies have
directly tested this hypothesis using a variety of conflict tasks but many of them failed to provide positive
evidence. Here, we examined changes in the spatial scopes of attention in human subjects performing a
variant of the Eriksen flanker tasks where they discriminated the shape of the cued target surrounded by
congruent or incongruent distractors. The spatial scopes of attention in the congruent and incongruent
conditions were indexed by the spatial reconstructions based on the modeling of spatially specific alpha band activity (EEG oscillations at 8-12Hz), which have been shown to track the precise location of covert
attention. We found that the scopes of the alpha-based spatial reconstructions were smaller in the
incongruent conditions compared to the congruent conditions and these conflict-induced modulations
occurred ~100-250 ms after stimulus onset. Moreover, we found that the degree of the reduction in the
spatial scope of attention predicted the degree of behavioral interference. These results provide neural
evidence implicating the important role of early attentional selection in conflict resolution at least in the context of our experimental design.