Perceptual psychology is a subfield of cognitive psychology that concerns the conscious and unconscious innate aspects of the human cognitive system: perception. A pioneer of the field was James J. Gibson. One major study was that of affordances, i.e. the perceived utility of objects in, or features of, one's surroundings. According to Gibson, such features or objects were perceived as affordances and not as separate or distinct objects in themselves. This view was central to several other fields as software user interface and usability engineering, environmentalism in psychology, and ultimately to political economy where the perceptual view was used to explain the omission of key inputs or consequences of economic transactions, i.e. resources and wastes.