Perception

Sliding Gray Step

This exhibit vividly demonstrates an interesting problem in the area of perception. Normally the brightness of an object is perceived relative to the brightness of the objects around it. A gray object should appear lighter surrounded by darker objects and darker while amongst lighter objects. This exhibit shows the exact opposite. When the gray stripes are between the black stripes they appear darker and when between white stripes they appear lighter. The reasons for this effect are not completely understood.