Lightness Perception and Lightness Illusions

Use of graphical user interfaces in information technologies requires special attention as there are many design issues that cannot be verified by automated processes and are result of human misperceptions.

 "Human lightness computation is imperfect, but performs well in most natural situations" is an underlying fact that fueled Edward H. Adelson's work. In the picture on the left, the check B in shadow is surrounded by darker checks. Thus, even though the check is physically dark and is the same shade of gray as the check A, it appears light when compared to its neighbors and eventually lighter then the check A.

This and similar illusions drawn from lightness, form or motion perceptions are researched by the PERSCI group  at the Massachusetts Institute of Technology and more of similar illusions are presented in the form of interactive movies  on their web site.