<p>(A) Individual observer data. Contrast thresholds (in log scale) for identifying target grating patterns presented in various degrees of eccentricity as a function of center-to-center distance between the target and flanking gratings. Error bars indicate the standard deviations (3 data points per condition was collected from each observer). Stimuli presented in this experiment were identical to those used previously in the CFS trials of the grating orientation discrimination experiment (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0028814#pone-0028814-g001" target="_blank">Figure 1A</a>). (B) The critical spacing of crowding (in degree) as a function of eccentricity (nβ=β2). Bouma's proportionality constant <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0028814#pone.0028814-Mudrik1" target="_blank">[23]</a> is illustrated here for reference.</p