The role of global configuration in detection of mirror and translational symmetries

Mirror symmetry is known as a special case of symmetric patterns because of its superior detectability. This study examined whether the perceptual advantage of mirror symmetry is maintained despite the absence of perfect symmetry. We manipulated the alignment of symmetric patterns by adding a vertical offset between left and right halves of them. We found that regularity of mirror symmetry was better detectable than that of translational symmetry in the aligned display. However, the advantage of mirror symmetry disappeared even with the smallest misalignment used in the present study. These results suggest that global configuration of pattern elements plays an important role in mirror symmetry detection.