Preconstancy information can influence visual search: the case of lightness constancy.

Can visual search be based on preconstancy representations of the scene--that is, ones in which accidental characteristics of the scene, such as shadows, point of view, and distance, have not yet been discounted? This question was addressed within the specific context of lightness constancy, the phenomenon that surface lightness is perceived as relatively unchanged despite changes in illumination conditions. Three experiments yielded evidence of preconstancy influence on visual search. This was true even when the preconstancy information that seemed to influence search was unavailable at a reportable level. The results suggest that visual search processes can be engaged before the processing that leads to the experienced perception of the scene is complete.