Cooperative interactions between coincident segmentations: Some restrictions

Summary We investigated the hypothesis that the detection of a scene segmentation is facilitated when coincident with a segmentation in another visual dimension. We measured the percentage of the correct detection of horizontal or vertical tritanopic color segmentations perpendicular to, or coincident with, segmentations produced by a subjective-contour stimulus. We found that color discrimination improves when the color segmentation is coincident with the segmentation formed by the subjective contour.In a second experiment, using a yes-no procedure, we found that sensitivity for the detection of luminance segmentations coincident with subjective-contour segmentations increased. However, the detectability of luminance segmentations coincident with a line deteriorated (the gap effect). We conclude that the notion of facilitated detection of coincident segmentations has several problems that undermine its intuitive appeal.