Some dynamic features of depth perception.

In this article we extend this observation and also describe how a subject’s ability to utiIize disparity cues in detecting a target’s movement is affected by the frequency of the target’s osciIIation. We report psychophysical findings which bear on the question whether the dynamic characteristics of binocular depth perception differ for stimuli located in front of, behind and near the plane of fixation. METHODS The subject used both eyes to view a fixation plane deSned by a random dot pattern which sutrtended a visual angle of 5” x 5” at a viewing distance of 75 cm. The Iominance of the bright parts of the background was 110 cd/m”. The dots in the fixation plane (whose purpose was to assist the subject to maintain steady convergence) occupied roughly 1 per cent of the background area and subtended some 1’. The upper half (15’ long) of the nonious line was seen by the left eye and the lower half by the right eye. When the two eyes converged correctly onto the flxation plane, the two halves of the nonious line were in register and appeared as a single vertical line. If convergence altered, the two halves separated. When the subject viewed the stimuius with both eyes he saw two vertical black bars (2“ x 73 aligned venicaffy one degree to either side of the central nonious line. The left hand bar was always stationary. It