The image here:

comes from a 2011 Nature Neuroscience paper entitled “Metamers of the Ventral Stream.” The intention is to provide a visualization of representation of printed text in the periphery.
In “Peripheral vision and pattern recognition: A review,” (Journal of Vision 2011), Hans Strasburger, et. al., write: “It is commonly thought that blurriness of vision is the main characteristic of [“seeing sidelong”]. Yet [Jerome] Lettvin [“On Seeing Sidelong,” The Sciences, 1976] […] insisted that any theory of peripheral vision exclusively based on the assumption of blurriness is bound to fail: “When I look at something it is as if a pointer extends from my eye to an object. The ‘pointer’ is my gaze, and what it touches I see most clearly. Things are less distinct as they lie farther from my gaze. It is not as if these things go out of focus—but rather it’s as if somehow they lose the quality of form””
In the image the red dot indicates where the ‘pointer’ touches down.
The science behind metamers is explained in the Nature Neuroscience paper available at: http://www.jeremyfreeman.net/public/downloads/Freeman-Simoncelli-2011-Me.... The Strasburger, et. al., paper is at: http://www.journalofvision.org/content/11/5/13.full.pdf+html.
In a 2012 (Journal of Vision) paper “A summary statistic representation in peripheral vision explains visual search,” Ruth Rosenholtz et. al., use this science to generate metamers or mongrels of patches of text or shapes, and to introduce a notion of patch discriminability. Applied to printed text, patch discriminability would translate to Hrant’s notion of bouma divergence. For Rosenholtz, et. al., visual patch discriminability using metamer stimuli predicts ease of visual search. So for our purposes, gauging patch discriminability might help us get a handle on and test the impact of bouma divergence (or optimizing notan) on the parafoveal preview benefit in reading.
It would be interesting to test using metamers of Moby Dick if the kind of manipulations Hrant envisions to enhance bouma divergence yield patches with significantly greater patch discriminability. Whether they do or not, the graphic appears to supply a more telling representation of what visual information is available to parafoveal vision then we've had until now.
The Rosenholtz paper is here: http://www.journalofvision.org/content/12/4/14
Peter



