Comparing two mechanisms for the perception of binocular motion in depth

摘要

It has been suggested that binocular motion in depth may be perceived via mechanisms sensitive to changing binocular disparity, or sensitive to inter-ocular velocity differences. I will start by describing how each source of visual information can be isolated. I will then review some of the evidence suggesting the use of each mechanism, and suggest how a signal-in-noise approach can be used to compare their relative utility. We have recently measured the ability to discriminate motion in depth of a population of naive observers. I will discuss how the natural variation between performance of different individuals can be used to provide support for the existence of two independent binocular motion in depth mechanisms. We have also found that not all observers appear to be sensitive to both mechanisms. In general, visual systems appear to rely mostly on the mechanism sensitive to changing binocular disparity, but perception of motion in depth is augmented by the presence of a (usually) less sensitive mechanism that uses interocular velocity differences. Occasionally, we find observers with the opposite pattern of sensitivity, suggesting that if one mechanism is compromised, the other may compensate.