Closure of salient regions determines search for a collinear target configuration

Grouping operations offer an effective mechanism by which to structure complex visual scenes. Among the various principles that support element integration, closure may be regarded as a main factor in shape extraction. In five experiments, we investigated the impact of grouping by closure on search for target configurations made up of collinearly arranged corner junctions. Systematic variations in the configuration of distractor elements were explored to investigate how the figural information of distractors interferes with target detection. The results showed no search interference for distractor configurations that were open forms. By contrast, distractors making up closed forms reduced the efficiency of search performance, indicating closure as a major contributor to form detection in multielement configurations. In conclusion, the effects reported may be considered to arise from mechanisms of unit formation that support the rapid extraction of salient regions to guide search.