On 2016 Apr 07, Lydia Maniatis commented:

Readers should read the last paragraphs of this article first. It indicates that the current results contradict the authors' previous results, and that they have no idea why that is. Nevertheless, they assume that one of the two must be right, and use a crude rule of thumb (the supposedly "simpler" explanation) to make their choice. I would take the third option.

"We see two possible explanations for the inconsistency between our previous work and that here:

The correct conclusions about the extent of contrast integration are drawn in our current work, with previous work being compromised by the loss of sensitivity with retinal eccentricity. For example, Baker and Meese (2011) built witch's hat compensation into their modeling, but not their stimuli (in which they manipulated carrier and modulator spatial frequencies, not diameter). A loss of experimental effect in the results (such as that in Figures 2a and 3a here) limits what the analysis can be expected to reveal. Indeed, Baker and Meese (2011) found it difficult to put a precise figure on the range of contrast integration, and aspects of their analysis hinted at a range of >20 cycles for two of their three observers. Baker and Meese (2014) made no allowance for eccentricity effects in their reverse correlation study. The contrast jitter applied to their target elements ensured they were above threshold, and so the effects of contrast constancy should come into play (Georgeson, 1991); however, we cannot rule out the possibilities that either (a) the contrast constancy process was incomplete or (b) internal noise effects not evident at detection threshold (e.g., signal dependent noise) compromised the conclusions.

The correct conclusions about the extent of contrast integration come from our previous work. Our current work points to lawful fourth-root summation, but not necessarily signal integration across the full range. On this account, signal integration takes place up to a diameter of about 12 cycles and a different fourth-root summation processes take place beyond that point. For example, from our results here we cannot rule out the following possibility: Beyond an eccentricity of ∼1.5° the transducer becomes linear and overall sensitivity improves by probability summation (Tyler & Chen, 2000), but uncertainty (Pelli, 1985; Meese & Summers, 2012) for more peripheral targets causes the slope of the psychometric function to remain steeper than β = 1.3 (May & Solomon, 2013).

We think Occam's razor would favor the first account over the second."

On 2016 Apr 07, Lydia Maniatis commented:

Readers should read the last paragraphs of this article first. It indicates that the current results contradict the authors' previous results, and that they have no idea why that is. Nevertheless, they assume that one of the two must be right, and use a crude rule of thumb (the supposedly "simpler" explanation) to make their choice. I would take the third option.

"We see two possible explanations for the inconsistency between our previous work and that here:

The correct conclusions about the extent of contrast integration are drawn in our current work, with previous work being compromised by the loss of sensitivity with retinal eccentricity. For example, Baker and Meese (2011) built witch's hat compensation into their modeling, but not their stimuli (in which they manipulated carrier and modulator spatial frequencies, not diameter). A loss of experimental effect in the results (such as that in Figures 2a and 3a here) limits what the analysis can be expected to reveal. Indeed, Baker and Meese (2011) found it difficult to put a precise figure on the range of contrast integration, and aspects of their analysis hinted at a range of >20 cycles for two of their three observers. Baker and Meese (2014) made no allowance for eccentricity effects in their reverse correlation study. The contrast jitter applied to their target elements ensured they were above threshold, and so the effects of contrast constancy should come into play (Georgeson, 1991); however, we cannot rule out the possibilities that either (a) the contrast constancy process was incomplete or (b) internal noise effects not evident at detection threshold (e.g., signal dependent noise) compromised the conclusions.

The correct conclusions about the extent of contrast integration come from our previous work. Our current work points to lawful fourth-root summation, but not necessarily signal integration across the full range. On this account, signal integration takes place up to a diameter of about 12 cycles and a different fourth-root summation processes take place beyond that point. For example, from our results here we cannot rule out the following possibility: Beyond an eccentricity of ∼1.5° the transducer becomes linear and overall sensitivity improves by probability summation (Tyler & Chen, 2000), but uncertainty (Pelli, 1985; Meese & Summers, 2012) for more peripheral targets causes the slope of the psychometric function to remain steeper than β = 1.3 (May & Solomon, 2013).

We think Occam's razor would favor the first account over the second."