Since the late 18th Century, scientists have used psychophysics to measure perceptual and sensory systems. Simply defined, psychophysics is, "The branch of psychology concerned with the effects of physical stimuli on mental processes" ( DaSilva & Ribeiro-Filho, 2006Da Silva, J.A., & Ribeiro-Filho, N.P. (2006). Avaliação e mensuração de dor: pesquisa, teoria e prática (Assessment and measurement of pain: research, theory and practice). Ribeirão Preto: Funpec, 467p.). However, psychophysics is both an area of study and a methodology. The investigation of human perception is centered on human experiences-at different levels of development or adaptation-of space, objects, and events, and of their dimensions. Wundt, in 1879, founded the first laboratory of experimental psychology in which studies about consciousness and perception included introspective methods ( Stevens, 1951Stevens, S.S. (Ed.) (1951). Handbook of Experimental Psychology. New York: Wiley.; 1975Stevens, S.S. (1975). Psychophysics: introduction to its perceptual, neural and social prospects. New York: Wiley.). Introspective methods in the field of perception and psychophysics were abandoned because of the lack of validity, reliability, and new developments in the field, with the advancement of technology and the appearance of animal psychology. For almost two centuries, scientists of human behavior-mostly psychologists-were intrigued with the possibility of measuring, predicting, and eventually explaining how humans perceive the world. The reliability of early investigations conflicted with the subjectivism of introspective techniques. Given the vast range of possibilities an individual has to express himself, in an experimental situation his impressions of a given stimulus lent little reliability to introspective methods (i.e., analytical insight). These methods left it open to the individual to describe (typically verbal replies) what he perceived about a stimulus. Studies on sensation and perception since psychometrics' early history have resulted in numerous applications, including: • Information theory (marketing, advertising, education, internet applications, intelligence) • Development of communication technology and radar systems (military use) • Space programs (humans outside of the terrestrial environment and effects of microgravity) • Artificial intelligence (human-machine analogies, computers, robots) • Ergonomics (implementation of service equipment in daily life activities, sport, work, leisure) • Rehabilitation (prostheses, implants, stimulation techniques, adaptations after intervention) • Public health (consumerism, hygiene habits, disease prevention, lifestyle choices) • Architecture and urban design (spaces and utilities, comfort and aesthetics, technological growth and demand) • Social behavior (mass behavior, perception of face and body image, public safety, institutional behavior, traffic, war) |