On 2016 Oct 01, Lydia Maniatis commented:

The logic of this study hinges on the following statement:

"The perceptual distance between colors was calculated using the receptor-noise limited model of Vorobyev and Osorio (1998; see also Table 1; Supplementary Figure S1), which has recently been validated experimentally (Olsson, Lind, & Kelber, 2015)."

In no sense is it legitimate to say that Olsson, Lind & Kelber have validated any models, as their own conclusions rest on unvalidated and implausible assumptions, specifically the assumption that the relevant discrimination thresholds " are set by photoreceptor noise, which is propagated into higher order processing."

This idea (versions of which Teller, 1984, described as the "nothing mucks it up" proviso), is not only untested, it is bizarre, as it leaves open the questions of a. how and why this "noise" is directly propagated unchanged by a highly complex feedback and feedforward system whose outcomes (e.g. lightness constancy, first demonstrated by W. Kohler to exist in chicks) resemble logical inference (and which are not noisy in experience), and b. even if we wanted to concede that the visual system is "noisy," (which is a bad idea) on what basis do we decide, using behavioral data, that this noise originates at the photoreceptor, and only the photoreceptor level? Many psychophysicists (equally illegitimately) prefer to cite V1 in describing their results.

The concept of "noise" is related to the also-illegitimate ideas that neurons act as "detectors" of specific stimuli and that complex percepts are formed by summing up simpler ones.

On 2016 Oct 01, Lydia Maniatis commented:

The logic of this study hinges on the following statement:

"The perceptual distance between colors was calculated using the receptor-noise limited model of Vorobyev and Osorio (1998; see also Table 1; Supplementary Figure S1), which has recently been validated experimentally (Olsson, Lind, & Kelber, 2015)."

In no sense is it legitimate to say that Olsson, Lind & Kelber have validated any models, as their own conclusions rest on unvalidated and implausible assumptions, specifically the assumption that the relevant discrimination thresholds " are set by photoreceptor noise, which is propagated into higher order processing."

This idea (versions of which Teller, 1984, described as the "nothing mucks it up" proviso), is not only untested, it is bizarre, as it leaves open the questions of a. how and why this "noise" is directly propagated unchanged by a highly complex feedback and feedforward system whose outcomes (e.g. lightness constancy, first demonstrated by W. Kohler to exist in chicks) resemble logical inference (and which are not noisy in experience), and b. even if we wanted to concede that the visual system is "noisy," (which is a bad idea) on what basis do we decide, using behavioral data, that this noise originates at the photoreceptor, and only the photoreceptor level? Many psychophysicists (equally illegitimately) prefer to cite V1 in describing their results.

The concept of "noise" is related to the also-illegitimate ideas that neurons act as "detectors" of specific stimuli and that complex percepts are formed by summing up simpler ones.