Of holes and wholes: The perception of surrounded regions

Fully enclosed regions in a two-dimensional image can often be perceived ei ther as an object in front of a surface or as a hole through a surface. Sev eral experiments were conducted to determine what factors affect perception of holes versus objects. Three types of factors were tested and found to i nfluence this outcome. First, depth factors directly indicate that the encl osed region lies behind its surrounding surface. Second, grouping factors r elate the enclosed region to an outer region that is generally perceived as a continuation of the surface seen through the hole. Finally, figural fact ors indicate whether the enclosed region is to be perceived as figure or gr ound. Relations among these factors and their implications for perceptual o rganization are discussed.