Abstract
In the visual search paradigm using shading stimuli it is suggested that concavity is more dominant than convexity. However, in a figure and ground segregation task, the opposite is true. We proposed that a discrepancy in dominance could be based on whether or not subjects identified the properties of objects such as shape and orientation, and we confirmed this in four experiments. The results of the first and second experiments showed that searching for and identifying items composed of convex disks was more efficient than items composed of concave disks. The results of the third and fourth experiments showed that in detection and localization tasks, there were no significant differences in the dominance between convexity and concavity. These results suggest that convexity is dominant when subjects conduct a task requiring identification of the properties of objects, and that the visual system extracts appropriate information according to task demand.
