Consideration of the range of phenomena from studies of human stereops
is suggests that a five-stage model is required to provide a complete
account of the processes involved, within which any stereoattention me
chanism must operate. The information from the disparity field of the
optical projections to the two eyes (stage 1) goes to a set of paralle
l Keplerian arrays of disparity detectors, each array selective for a
different spatiotemporal property of the visual images (stage 2). Glob
al interactions produce a cyclopean depth image that is cleaned of the
spurious ghost images in the Keplerian arrays (stage 3) and that may
then be processed for its (hypercyclopean) form elements (stage 4). Fi
nally, there must be a stage of integration of the stereoscopic depth
cues with monocular and kinesthetic depth cues to form the overall map
of perceived distance (stage 5). The fact that multiple cyclopean sur
faces may be perceived as transparent implies that the stereoscopic sy
stem is not limited by a singular-surface constraint. However, it is u
nclear whether multiple surfaces can be seen simultaneously or whether
only one surface is seen at a time by a selective-attention process,
with the others perceived as a purely inchoate (qualitative) depth imp
ression. New experiments on cueing of ambiguous stereocorrugations by
singular flat planes suggest that selective stereoattention is a power
ful mechanism. In fact, the results show that attention can be focused
not just in horopteral planes but in a variety of depth configuration
s. Moreover, this attention focus may act as a tracking mechanism to a
llow perception of smooth cyclopean stereomotion, which has a frequenc
y response up to similar to 5 Hz (in contrast to the similar to 15 Hz
limit for detecting planar disparity shifts as jerky appearance and di
sappearance effects). Finally, the spatial limits of stereosurface rec
onstruction are explored with cyclopean targets to show some interesti
ng asymmetries of the surface-wrapping process that may represent obje
ct-oriented constraints on depth reconstruction.