Feature-based attention modulates the perception of object contours

Feature-based attention is known to support perception of visual features associated with early and intermediate visual areas. Here we examined the role of feature-based attention in higher levels of object processing. We used a dual-task design to probe perception of poorly attended contour-defined or motion-defined loops while attention was occupied with congruent or incongruent feature detection tasks. Perception of the unattended task was better when concurrently presented with a congruent stimulus. However, this effect was eliminated when detection of the primary task was made easy suggesting that task-demand in object perception is feature specific. Our results provide evidence for the contribution of feature-based attention to object perception.