Cognitive neuroscience researchers Catherine Q. Howe, Zhiyong Yang, and Dale Purves have released a new paper titled, The Poggendorff Illusion Explained by Natural Scene Geometry (PDF format). The Poggendorff illusion is a common optical illusion studied by neuroscientists as well as machine vision researchers. "Johann Poggendorff pointed out in the 19th century that when the continuity of an obliquely oriented line is interrupted, the positions of the line segments on either side of the interruption appear to be shifted". The paper proposes that the human brain generates the illusion by applying accumulated experience statistically learned from interrupted lines found in scenes viewed in our natural environment. In other words, our brain shifts the lines to correspond to their statistically most likely path had the scene occurred in the real world. For more, including animated demonstrations of other optical illusions visit the Dale Purves Lab.