“…The underlying assumption was that the more that subjects fill-in illusory contours, the more that distractors would impair discrimination in the illusory relative to the fragmented condition. This second metric was chosen because others have shown that distractor lines near the edges of Kanizsa shapes worsen illusory shape perception, but exercise little, if any effect when illusory contours are blocked (Keane, Lu, et al, 2012, 2013; Ringach & Shapley, 1996; Zhou, et al, 2008). Reverse correlation and other studies have also revealed filling-in by examining behavioral or neural responses to line segments or luminance noise placed near filled-in boundaries (Dillenburger & Roe, 2010; Dresp & Bonnet, 1991; Dresp & Grossberg, 1997, 1999; Gold, et al, 2000; Gold & Shubel, 2006; Keane, et al, 2007; Keane, Lu, et al, 2013).…”