In boundary extension (BE), people confidently remember seeing a surrounding region of a scene that was not visible in the studied view. However, the content near image boundaries might be uninteresting, serving only as a background for a central figure.In our experiments, we presented participants with 24 photographs with a defect (cut-out hole or black ink blot). Participants were instructed to memorize the photograph and then either reproduce the size of the hole/blot (BE task) or identify a change (distractor task). In Exp. 1, we showed participants printed photographs (18×13 cm) with cut-out holes. Participants systematically drew smaller holes (87.5% diameter, N=32). When we replaced the holes with black ink blots (Exp. 2), the bias was still present (91.4%, N=30). The computer-based version with size-adjustment of black blots (Exp. 3) yielded similar effects (92.8%, N=30), which disappeared (Exp. 4, 100.7%, N=30) if the probe blot sizes were randomized.We argue that BE occurs in the internal parts of photographs. We explored the effect in different media (paper/screen) and using different response tasks (free recall/adjustment). People show uncertainty in the adjustment tasks and reproduce remembered holes/blots as smaller (consistent with BE) if they are presented with the occluded content in the response phase.
Relationship between metamorphopsia and inner retinal microstructure following intravitreal ranibizumab injection for branch retinal vein occlusion
