New research has been carried out after the first, presented 2 years ago in West-Berlin (IAPS-8; P. Bonaiuto, M. Miceu Roman, F. Bonaiuto, 1984). The research contributes to show that, when we observe highly irregular and pa- radoxical buildings, under ambiguous perceptual conditions, because of the influence of mental schemata we attenuate the anomalies. But we increase and emphasize them, if the perceptual conditions are univocal and coercive. In such opposite phenomena, respectively, assimilation and contrast after-effects are involved. The demonstration of these phenomena has been confirmed by experiments on the perception of three-dimensional models of leaning buildings The very consistent individual differences have also allowed us to define 5 different cognitive styles. This research paradigm is also successfully applied in predicting and explaining similar phenomena which occur during the perception of architectural facades with characteristics of disorder (i.e. windows not lined up).