Information processing models of visual perception attempt to relate the elements of vision to each other via structural theory and confirmative behavioral tests. This paper reviews studies of the major dichotomy of preattentive versus attentive vision and the attributes of each. For example, visual search for objects with a single characteristic can be done preattentively, but a conjunction of characteristics requires attentive search. Use of a visual attention distractor degrades the search for a conjunction. New work is reported on the perception of the absence of a feature, showing it to belong to the attentive phase.