Mirror image reversal: is what we see what we present?Perception. 1993; 22(7):869-76.P
Many psychological explanations have been advanced to explain left-right reversal in mirror images, but Gregory and Haig have each proposed a physical explanation for the reversal: the first is based upon the physical rotation used to present the surface of the object to the mirror, and the second on the classical optics of reflection. These physical explanations are considered together with an explanation based on object symmetry. The apparent reversal of directional coordinates (eg left and right) that occurs in the mirror images of most objects is distinguished from reversals achieved by physical or mental rotation. It is also distinguished from the object-image match that can be achieved by mental or physical rotation of some symmetrical objects. It is concluded that the left-right reversal is not specifically optical, but is determined by multiple factors, including object symmetry, the conventional and gravitational positioning of top and bottom and back and front, and our greater familiarity with right-left than with top-bottom or back-front reversals.