Color Perception: the perceptual experience of different wavelengths of light, involving "hue,"  "saturation," and "brightness." (Hockenbury, 94) We can describe all the colors we can perceive by using the terms red, yellow, green, blue and their combinations. (Goldstein, 203) The perception of color is associated with the physical property of wavelength. (Goldstein, 204) Color perception involves numerous neurons, and is influenced not only by the distribution of wavelengths from the viewed object, but also by its background color and brightness contrast at its boundary. (MeSH)

Opponent-Process Theory: theory that color vision is the product of opposing pairs of color "receptors," red-green, blue-yellow, and black-white; when one member of a color pair is stimulated, the other member is “inhibited.” (Hockenbury, 95) Caused by opposing responses generated by blue and yellow and by red and green. (Goldstein, 213)

Trichromatic Theory: the theory that the sensation of color results because ”cones” in the “retina” are especially sensitive to red light, green light, or blue light. (Hockenbury, 94)

Depth Perception: the ability to perceive the distance of an object as well as the three-dimensional characteristics of an object. (Hockenbury, 111) The cues that provide information about depth are called 'pictorial cues.' (Stone, 117) Pictorial cues are sources of depth information that can be depicted in a picture. (Goldstein, 231)

Binocular: cues to judge the distance of objects. Requires information from both eyes. (Hockenbury, 112) Also referred to as 'binocular cues."

Binocular Convergence: the degree to which muscles rotate your eyes to focus on an object. The more the eyes converge, or rotate inward, to focus on an object, the greater the strength of the muscle signals and the closer the object is perceived to be. For example, holding a dime in front of the nose, the eye muscles strain to converge as the dime gets closer. Perceptually, the info provided by these muscle signals is used to judge the distance of an object. (Hockenbury, 113) Also referred to as ‘convergence.’

Binocular Disparity: the difference in the images in the left and right eyes. (Goldstein, 235) When the two retinal images are very different, we interpret the object as being close by. When the two retinal images are more nearly identical, the object is perceived as being farther away. (Hockenbury, 112)

Stereogram:  a picture that uses the principle of binocular disparity to create the perception of a three-dimensional image. (Hockenbury, 113) If you placed a camera in front of each of your eyes than the resultant pair of pictures would be a stereogram. (Stone, 141)

Monocular: images seen by one eye. (MeSH) Cues to judge the distance of objects. Require the use of only one eye. (Hockenbury, 111) Also referred to as 'monocular cues."

Aerial Perspective: faraway objects often appear hazy or slightly blurred by the atmosphere. (Hockenbury, 111)

Linear Perspective: parallel lines seem to meet in the distance.  The closer together the lines appear to be, the greater the perception of distance. For example, railroad tracks. (Hockenbury, 111) When parallel lines extend out from an observer, they are perceived as converging - becoming closer together - as distance increases. (Goldstein, 231) Also referred to as 'perspective convergence.'

Motion Parallax: occurs when, as we move, nearby objects appear to glide rapidly past us, but more distant objects appear to move more slowly. (Goldstein, 233) Caused by the differential speed with which stationary objects move across the retinal image. Its effects tell you about the relative distances of objects in the world. (Stone, 122) When you are moving, you use the speed of passing objects to estimate the distance of the objects. Nearby objects seem to zip by faster than do distant objects. For example, riding on a train. Houses and parked cars along the tracks seem to whiz by, while the distant downtown skyline seems to move very slowly. (Hockenbury, 111)

Overlap: when one object partially blocks or obscures the view of another object, the partially blocked object is perceived as being farther away. (Hockenbury, 111) Also referred to as ‘interposition.’

Relative Size: when two objects are of equal size, the one that is farther away will take up less of your field of view than the one that is closer. (Goldstein, 231) If two or more objects are assumed to be similar in size, the object that appears larger is perceived as being closer. (Hockenbury, 111)

Texture Gradient: if you are looking at a scene that contains texture then the rate at which texture changes across the image tells you about the slant of surfaces in that scene. (Stone, 118) As a surface with a distinct texture extends into the distance, the details of the surface texture gradually become less clearly defined. The texture of the surface seems to undergo a “gradient,” or continuous pattern of change, from crisp and distinct when close, to fuzzy and blended when farther away. (Hockenbury, 111) 

Occulomotor: cues based on our ability to sense the position of our eyes and the tension in our eye muscles. (Goldstein, 230) Also referred to as 'occulomotor cues."

Occlusion: if one object is in front of another then your view of that object is obscured or 'occluded,' so that occlusion tells you about the relative depth of objects. (Stone, 117) (Also), the obstruction or closure of a hollow organ, passageway or vessel. (NCIt)

Shape Perception: the shape of a three-dimensional object can be inferred from its "texture" or from its "shading." (Stone, 147) The perception of countless distinct objects against a variety of backgrounds. We perceive these, we don’t perceive random edges, curves, colors, or splotches of light and dark. Although to some degree we rely on size, color, and texture to determine what an object might be, we rely primarily on an object’s shape to identify it. (Hockenbury, 107)