Abstract
Studies show that figure-ground perception entails competition between shapes that might be seen on opposite sides of a border. We presented small, enclosed, symmetric novel silhouettes designed to favor the inside as figure, but to differ in the strength of competition from shapes that might be seen on the outside. In high-competition silhouettes, a portion of a familiar shape was suggested, but not perceived, on the outside of the figure's border. In low-competition silhouettes, the shape suggested on the outside was novel. We used a target orientation discrimination task in which tilted bar targets were presented on the inside or outside of high-competition and low-competition silhouettes to assess whether: (1) More attention was drawn to the inside to resolve the greater competition from the outside in high- than low-competition silhouettes; if so, RTs should be faster for targets on the inside of high-competition than low-competition silhouettes. (2) More inhibition was applied to the outside of the high-competition than low-competition silhouettes because of the greater competition from the outside in the former than the latter; if so, RTs should be longer for outside targets shown with high-competition than low-competition silhouettes. (3) Whether cross-border competition involves mutual inhibition; if so, RTs should be longer for both inside and outside targets shown with high-competition compared to low-competition silhouettes. For both inside and outside targets, accurate discrimination responses were significantly slower for targets shown with high-competition than low-competition silhouettes (p <. 05). Thus, our results support the hypothesis that competition for figural status entails mutual inhibition of the competing shapes. We find no evidence that more attention is deployed to the inside to resolve the greater competition in high-competition than low-competition silhouettes. Nor do we find that inhibition is applied only to the outside of high-competition silhouettes, where the strong competitor lay.