Human visual perception is a fundamentally relational process: Lightness perception depends on luminance ratios, and depth perception depends on occlusion (difference of depth) cues. Neurons in low-level visual cortex are sensitive to the difference (but not the value itself) of signals, and these differences have to be used to reconstruct the…

The explanation of certain 3D concepts is based on 2D drawings. These drawings should contain certain depth cues, such as perspective and overlapping. Until recently, parallax has not been used as a depth cue. Nevertheless, new technologies allow it to be incorporated. This forms the background to our study of the design of interactive educational…

A developmental study of the relation between apparent size and pictorial depth demonstrated the usefulness of operant techniques in establishing equivalent differential responding and interesting stimulus equivalence in adults, 9- and 3-year-olds. (Author/AJ)

Three groups of Nigerian high school and college students were tested for response to four pictorial depth cues. Students had more difficulty with cues concerning the relative size of objects and the foreshortening of straight lines than with cues involving overlap of lines and distortion of the angles between lines. (Author/JEG)

Investigates the effect of orientation of depth cues on the magnitude of perceived depth in pictures. Finds that, for each test drawing, the orientation with the far point above the near point provided greater depth perception than any other orientation. Discusses possible contributions of observer experience and height of visual field. (DSK)

Young children drew two opaque objects placed one behind the other. Over two-thirds of the children drew the objects separately in horizontal or vertical relationships. When drawing an object in a glass beaker, half of the children depicted the object vertically or horizontally separate from the beaker. (Author/DB)

Describes experiments which focus on the perception of three dimensions. Discusses the cues about distance and depth and the role they have in perceptions of three dimensions. Evaluates the effect of color on the illusion on depth. (ML)