Abstract
We define a novel percept that we call dichoptic completion. This occurs when the image shown to one eye closely resembles an amodal completion of the image shown to other eye. In this case, the perception is a form of superposition that is distinct from the result of either binocular summation or a process of rivalry when only content in one image is seen at each location. For example, if the left eye image contains a red square partly occluding a green square, and the right eye image contains the same two squares at the same respective image locations except that the green square is partly occluding the red one, subjects typically see both squares with all the occluding and occluded borders visible, as if the squares were simultaneously transparent. At the image locations where the two squares overlap, both red and green colors are visible simultaneously, contrary to normal perception in which red and green at the same image location is difficult, but subjects never report the yellow color which would result from binocular summation. In prolonged viewing, dichoptic completion often occurs for a longer accumulated duration than rivalry. Another illustrative example involves retinal images corresponding to the two standard alternative interpretations of a Necker cube. From each interpretation, one can produce a retinal image containing the three surfaces of this cube when it is made opaque. The image produced from the other interpretation contains the other three surfaces of the cube. The dominant resulting percept is of a transparent cube containing all six surfaces, even though two luminance edges in one image cross two luminance edges in the other image in an arrangement that conventionally tends to produce binocular rivalry.
The Gatsby Charitable Foundation, and Tsinghua University 985 grant.