Ponzo错觉解释的合理性：倾斜恒常性理论的局限

倾斜恒常性理论是一种新的解释Ponzo错觉的理论，但是似乎存在一些局限。本研究采用调节法通过两个实验考察了四种Ponzo错觉版本在各种条件(视角和水平线段间距)下的错觉量情况，以此来检验倾斜恒常性理论。实验一中，对称Ponzo错觉变异版本在50mm时的错觉量情况和Prinzmetal(2001)的结果相似，但是在85mm和120mm时得到了较多的错觉量，这和倾斜恒常性理论的理论预期不符。实验二对不对称Ponzo错觉的考察得到了和实验一类似的结果，只有50mm时的情形符合倾斜恒常性理论预期。通过以上实验得到水平线间距和视角因素都是产生Ponzo错觉的重要因素，而倾斜恒常性理论过分强调了背景线的倾斜诱导效应，忽略了其他结构因素对Ponzo错觉的影响，所以倾斜恒常性理论具有一定的局限性，不能有效地解释Ponzo错觉的产生机制。

Explainable Reasonability of Ponzo Illusion: the Limitation of Tilt Constancy Theory

Tilt constancy theory is a new but limited theory that explains Ponzo illusion. The theory claims that the tilt induction effect of tilt background line made the subjects have the different perception of two horizonal lines. But other researchers had the different opinions from the Prinzmental’ result. All of the disputes seemed to be reflected the limitation existed in the theory. The method of adjustment was employed. In experiments，the fixed design was 2(viewpoints:6°，2°)×2(illusion versions: standard, rectilinear) ×2(distances of horizontal lines: 50mm，85mm and 120mm). In experiments，the subjects were asked to adjust the distances of horizontal lines below by the key“PgDn”and“PgUp”. Until they thought the distances of horizontal below that equaled the ones above. AVOVA was employed to analyze the figures calculated by the illusion magnitude formula. In Experiment 1, the illusion magnitude of symmetrical rectilinear version of Ponzo illusion was obtained the same as which Prinzmetal(2001) got when the distance of horizontal line was set to 50mm.However,under the condition of 85mm and 120mm,we got more magnitude of illusion than that of the previous results, the different results mismatched with the tilt constancy theory. In Experiment 2, we got the same magnitude as the former one. The results in the research reflectal that：（1）The result form the Prizmental could be seem in the specific condition.（2）Tilt constancy theory had its limitation，it can’t explain the production mechanism of Ponzo illusion in the all conditions.（3）The tilt background line was the important factor influencing the illusion magnitude. The mechanism isn’t the tilt induction effect，but the perception difference of the included angle of the background line.(4)Viewpoint and the distances of the horizontal lines were both the major factors influencing the Ponzo illusion magnitude.