<p><i>Panel A</i> illustrates the design used in Experiment 2, which is identical to that used in Experiment 1: 57 points belonging to the inner area of a square (side length: 16.3 degrees of visual angle) were presented. 56 points were distributed along 8 radii (from 0° to 315°) at 7 equally-spaced locations for each radius (labels 1 to 7). The remaining last point coincided with the center of the square. <i>Panel B</i>. The experimental procedure was the same as in Experiment 1. As in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0151488#pone.0151488.g001" target="_blank">Fig 1B</a>, expected results are illustrated by the curve <b>C</b> which represents the hypothetical modulation of estimation error between the center and the periphery. The black curve represents the empirical contour line of null error actually estimated by participants in Experiment 2.</p
