Summary: Authors' update
The target paper reviewed in this article was titled ``Transparency: relation to depth,
subjective contours, luminance, and neon colour spreading'' coauthored by K Nakayama,
S Shimojo, and V S Ramachandran, published in 1990. This paper, one of the first in
a series on surface perception, examined how in untextured stereograms, local dispar-
ity and luminance contrast can drastically change surface quality, subjective contours,
and the effect of neon colour spreading. When we began to conceive this and related
work, the ascendant view on visual perception was derived from the pioneering studies
of the response properties of visual neurons with microelectrodes, including those of
Barlow (1953), Lettvin et al (1959), and Hubel and Wiesel (1959, 1962). All suggested
that there are remarkable operations on the image by earliest stages of the visual pathway,
which bestowed selectivity to colour, orientation, motion direction, spatial frequency,
binocular disparity, etc. As such, it would seem that an understanding of vision would
come through more systematic description of the properties of single neuron selectivities.
This viewpoint was well summarised by Horace Barlow in his famous neuron doctrine
paper (Barlow 1972), which emphasised the importance of analysing the image in
successive stages of processing by neurons with specific classes of receptive fields.
Later work altered this conception somewhat by seeing receptive fields as linear filters.
Rather than detecting the presence of edges, bars, or otherwise perceptually identifiable