Perceptual constancy

Suppose now there is presented a circular disc, first directly before us in the frontal plane where it is of course seen as circular, and then in a position titled away from us so that the image it produces on our retinas is elliptical in shape. We still tend under the latter conditions to see the disc as circular, not as elliptical. We do not however, see it as perfectly circular, but as a compromise that favors the circular more than the elliptical form. This is the phenomenon of perceptual consistency. It preserves for us consistency of appearance and thus the means of recognizing and identifying objects when they are seen at different angles or in different distances and of colors and brightnesses under differing conditions of illumination. Cues given by the object and surroundings enter intimately into perceptual constancies. There cues seem to be utilized in agreement with past experience and for the most part they give us fairly veridical perceptions.