Visual Stimuli

A stimulus is usually thought of as some physical event, or set of events, that is likely to lead to a sensory, perceptual, or behavioral response. The concept has its roots in sensory physiology, in the study of sensation and perception, and in behavioral psychology. Although it seems straightforward to consider a flash of light to be a stimulus for vision, the concept is more difficult than it seems. For example, the flash of light at its source (the distal stimulus) and the light that reaches the cornea and then the retina of the eye (the proximal stimulus) are different and need to be distinguished. Some theorists, notably J. J. Gibson, have argued that the concept should be abandoned altogether on the grounds that perceptual ...