The objective of the investigation was to develop and test procedures for training children in coordination of projective space. (Projective concepts involve apparent distance, relative position, shape of figures, and other topological factors. A person with a command of projective space sees objects as a coordinated system of figures in space.) A…

The present paper is concerned particularly with the processes underlying the perception of the upright, that is, an object in its usual, or familiar, position in space. (Author/RK)

Seven-year-olds compared successively presented oblique lines which varied as to their position within a square display and their relation to the diagonal axis of the display. Children apparently encoded lines in terms of position and axis features. They used a categorical spatial representational system to compare oblique lines. (Author/RD)

Various theories are introduced to explain illusions in which the length, orientation, curvature or direction is wrongly perceived. The role of eye movements in the process of diminution is discussed. (SA)