Does a color difference between parts impair the perception of a whole? A similarity between simultanagnosia patients and healthy observers.

In three experiments, participants decided whether a Star of David shape was present among distractors. Although the participants were instructed to ignore the colors in the display, detection was slower when each triangle of the Star of David was printed in a different color than when the Star of David was printed in a uniform color or when each triangle was in two colors. Extending the object file theory, we suggest that when the parts of an object are distinguished by a color difference and are perceived as separate objects, the perception of the whole object, which is composed of these same parts, is damaged. One interpretation within object file theory is that when the visual system represents the location of a complex object as occupied by identity tags for its different parts, it cannot also link the same location to the identity of the complex object. A new object file must then be created.