2 The Nature of Selectivity in Early Human Vision

Publisher Summary This chapter discusses the selective nature of processing at the earliest stages of vision in humans. “Selectivity” refers to the processing of some information at the expense of other information. Visual selectivity can be based on spatial considerations, on temporal considerations, and on geometric properties. In visual search, certain types of stimulus structures are processed rapidly and in parallel across the image. Thus, structure drives processing. The only issue, then, is the specification of the types of stimulus structures that are included. The chapter analyzes the possible function of early vision (i.e., object description), nature of the early processing system (i.e., the rapid, parallel processes of early vision), and some important characteristics of the stimulus (i.e., light from the scene is projected onto an image), which suggest that a plausible place to begin looking for features of early vision might be at the level of scene-based object properties.