| A | B |
|---|
| Trichromatic theory | The theory of color vision holding that the human eye has three types of receptors with differing sensitivities to different wavelengths. |
| Perceptual set | A readiness to perceive a stimulus in a particular way. |
| Phi phenomenon | The illusion of movement created by presenting visual stimuli in rapid succession. |
| Pictorial depth cues | Clues about distance that can be given in a at picture |
| Place theory | The idea that perception of pitch corresponds to the vibration of different portions, or places, along the basilar membrane. |
| Proximal stimuli | The stimulus energies that impinge directly on sensory receptors |
| Psychophysics | The study of how physical stimuli are translated into psychological experience. |
| Pupil | The opening in the center of the iris that helps regulate the amount of light passing into the rear chamber of the eye. |
| Receptive field of a visual cell | The retinal area that, when stimulated, affects the ring of that cell. |
| Retina | The neural tissue lining the inside back surface of the eye; it absorbs light, processes images, and sends visual information to the brain. |
| Retinal disparity | A cue to the depth based on the fact that objects within 25 feet project images to slightly different locations on the left and right retinas, so the right and left eyes see slightly different views of the object. |
| Reversible figure | A drawing that is compatible with two different interpretations that can shift back and forth. |
| Rods | Specialized visual receptors that play a key role in night vision and peripheral vision. |
| Sensation | The stimulation of sense organs. |
| Sensory adaptation | A gradual decline in sensitivity to prolonged stimulation. |
| Signal-detection theory | A psychophysiological theory proposing that the detection of stimuli involves decision processes as well as sensory processes, which are inuenced by a variety of factors besides the physical intensity of a stimulus. |
| Subjective contours | The perception of contrours where none actually exist. |
| Subliminal perception | The registration of sensory input without conscious awareness. |
| Subtractive color mixing | Formation of colors by removing some wavelengths of light, leaving less light than was originally there. |
| Top-down processing | In form perception, a progression from the whole to the elements |
| Visual illusion | An apparently inexplicable discrepancy between the appearance of a visual stimulus and its physical reality. |
