Role of symmetry in pattern reproduction

The role of enantiomorphs (mirror images) as units of coding of symmetrical patterns was investigated. Simple symmetrical matrices were presented tachistoscopically for 0.3 sec and were immediately followed by 0.3 sec presentation of the same matrix but with half of its cells occluded. The subjects were required to reproduce the first matrix. Five patterns of occlusion were used: random, lateral, skew, vertical and horizontal. It was found that lateral occlusion (which leads to a display of an enantiomorph) did not differ in its effectiveness from horizontal and vertical occlusions, although it conveyed twice as much information. Lateral, horizontal and vertical occlusions all differed significantly from the other two types which gave inferior results. In another experiment the effects of random and symmetrical occlusions were investigated; it was found that random occlusion was more effective than symmetrical occlusion. The results of the experiments, it is argued, show that information theory and gestalt approaches to the problem of symmetry are to some extent complementary.