Salient visual targets superimposed on motion distractors are perceptually grouped and disappear simultaneously (motion-induced blindness: MIB). Using the simultaneous disappearance of targets as a measure of grouping strength, we investigated the spatial effective ranges of each perceptual grouping cue in terms of analyzing the interactions between proximity and closure and between proximity and similarity grouping cues. We presented two stimuli in which a solid square was embedded in an outlined square as visual targets. We manipulated the separation between the targets (0.2 to 0.8 degrees) and the closure level of the outer contour (Experiment 1), and the orientation difference between the targets (0˚ to 45˚) (Experiment 2). The task was to report whether the targets disappeared simultaneously or independently during stimulus presentation. The results showed that the proximity cue influenced the simultaneous disappearance of targets most in less than 0.2 deg of separation between the targets. The closure cue increased the simultaneous disappearance in separations between 0.4 to 0.6 deg, and the similarity cue served to enhance the simultaneous disappearance in separations exceeding 0.6 deg. Thus, the visual system weighs each perceptual grouping cue depending on the spatial distance between visual stimuli, thereby modulating the interaction magnitude of multiple cues.（本研究では、運動誘発盲における複数のターゲットの消失パタンを用いて、知覚的群化の手がかりが影響する空間範囲を検討した。その結果、近接手がかりは、ターゲット間の距離が0.2度未満の条件で、複数のターゲットを同時に消失させた。閉合手がかりは、ターゲット間の距離が0.4〜0.6度で、類同の手がかりは、ターゲット間の距離が0.6度を超える場合に、ターゲットの同時消失を促進した。）
Michiaki Shibata, Yousuke Kawachi, Jiro Gyoba.
