REFERENCE PATTERNS AND THE PROCESS OF NORMALIZATION

Two experiments investigated the effect of reference patterns on the normalization process that involves the visual code. In experiment 1, subjects had to classify as same or different 2 simultaneously presented letters. The upper letter was always in the upright position, while the lower letter could take 6 different orientations and was enclosed in a congruent triangular frame. The results for same responses showed reliable orientation-dependent effects which implied an operation of normalization. In experiment 2, the orientation of the upper letter and that of its frame varied orthogonally, while the lower letter was always presented within a congruent frame at 6 different orientations. The normalization occurred with reference to the orientation of the upper letter, and the congruent upper frame could speed up the comparison process only at certain orientations of the lower letter. Apparently, the direction of normalization depends on the orientation of the upper letter; the effect of the frame is interpretable in terms of a display symmetry facilitation effect.