Wenderoth P, Parkinson A, White D
Perception. 1979;8(1):47-57. doi: 10.1068/p080047.
The tilt illusion (TI) was investigated by using both short (19 min) and long (2 deg 6 min) test lines, at three angles of test line-inducing line separation (15 degrees, 45 degrees, and 75 degrees). Three groups of ten observers each provided data under one of three task conditions: vertical judgment, parallel matching, and dot alignment on a common visual display. The main result was that both the vertical judgment and the parallel matching task provided similar, classic TI angular functions with the means ordered 15 degrees greater than 45 degrees greater than 75 degrees and with small attraction effects at 75 degrees in three of the four relevant functions. The third task, dot alignment, yielded results different from the average of the other two: no attraction effects occurred and, with the short test line, the obtained mean illusion at 45 degrees exceeded those at the other intersect angles. These results are consistent with alignment data reported by others. One explanation is that the inducing line produces an apparent bowing of the test line which would be reflected in dot alignments but not in vertical setting or in parallel matching. However, direct evidence does not support this hypothesis. An alternate hypothesis, for which independent evidence exists, is that alignment errors reflect perceptual mistracking but that the origin of these errors is not the tip of the test line but within it. Although this does not explain dot alignment errors, it highlights their complexity and the need to interpret them with caution.
采用短（19分钟）和长（2度6分钟）测试线，在测试线与诱导线分离的三个角度（15度、45度和75度）下对倾斜错觉（TI）进行了研究。三组观察者，每组十名，在三种任务条件之一（垂直判断、平行匹配和在共同视觉显示器上的点对齐）下提供数据。主要结果是，垂直判断和平行匹配任务都提供了相似的经典TI角度函数，其均值顺序为15度大于45度大于75度，并且在四个相关函数中的三个函数中，75度时存在小的吸引效应。第三个任务，点对齐，产生的结果与其他两个任务的平均值不同：没有出现吸引效应，并且在短测试线的情况下，45度时获得的平均错觉超过了其他相交角度时的平均错觉。这些结果与其他人报告的对齐数据一致。一种解释是，诱导线会使测试线产生明显的弯曲，这会在点对齐中体现出来，但在垂直设置或平行匹配中则不会。然而，直接证据并不支持这一假设。另一种有独立证据支持的假设是，对齐误差反映了感知上的跟踪错误，但这些错误的根源不是测试线的尖端，而是在测试线内部。虽然这并不能解释点对齐误差，但它突出了它们的复杂性以及谨慎解释它们的必要性。
