Abstract
While an impression of 3D space is attainable through binocular viewing of pictorial scenes, monocular viewing through an aperture of the same scenes provides a stronger sensation of depth and negative space; objects feel more tangible and real. We had observers actually reach into pictorial spaces under both binocular-aperture and monocular-aperture viewing conditions. We created 3D landscape scenes with varied depth separation, and marked different points in the scenes with colored dot targets. Images of these scenes were presented to observers at two different distances using a mirror reflection system. These images were scaled so that they would have the same retinal size. We asked observers to reach out and “touch” the points in space where they perceived the target dots to be with intermixed viewing and distance conditions. We measured the 3D point in space of their finger tip at the end of each reach movement. Importantly, we found that, under the binocular condition, the observers depth judgments were primarily based on the image distance, while in the monocular condition, their responses were modulated by the pictorial depth in the scenes instead of the image distance. These pictorial depths were similar in both distance conditions, indicating that observers perceived a consistent pictorial space in the monocular condition. Monocular-aperture viewing of pictorial scenes thus does provide a stronger sensation of depth which can be explored by motor actions.