Mentor
Dr. Shaun Vecera
Participation year
2009
Project title

Consequences of Figure-Ground Perception: Attentional Spreading and Spatial Resolution

Abstract
This experiment investigated how figure-ground assignment mediates the perceptual segregation of textures. Both figure-ground assignment and attention have been shown to enhance a target stimulus' spatial resolution and accelerate perceptual processing. In a texture-segmentation task in which performance peaks at mid-periphery and drops at both central and peripheral locations, attention improves performance at peripheral locations but hinders performance at central locations (Yeshurun & Carrasco, 1998). Our experiment tested if these attention-based effects can occur for figure-ground assignment as well. In a visual search task, observers detected the presence or absence of a texture-target whose orientation differed from the background texture. Targets appeared at one of four possible locations, and half of the targets were on a figure object. The other half were located on a ground object, which was shadowed and occluded by the figure. Our results indicated figure-ground processes, like attentional processes, produce a peak texture segmentation performance at mid-peripheral target eccentricities. However, at all measured target eccentricities, targets appearing on figure objects were detected more accurately than targets appearing on ground objects. We propose that attention is able to spread through figure regions more quickly, conferring processing benefits that extend across the figure and lead to improved target detection at peripheral locations. These results indicate an interesting interaction between figural assignment, the spread of attention within objects, and the peripheral detection of texture targets.
Elizabeth  Musz
Education
Carleton College