Armstrong L, Marks L E
John B. Pierce Laboratory, New Haven, CT 06519, USA.
Percept Psychophys. 1997 Nov;59(8):1200-13. doi: 10.3758/bf03214208.
Six experiments examined orientation-specific effects of stimulus context on the visual perception of horizontal and vertical lengths: Using a paired-comparison method, Experiments 1-5 showed that the probability of judging a given vertical line to be longer than a given horizontal line was relatively great when the stimulus set comprised relatively long horizontals and short verticals, and relatively small when the stimulus set comprised short horizontals with long verticals. To the extent that stimulus context exerts orientation-specific effects on perceived length, it thereby modulates the degree to which verticals appear longer than physically equivalent horizontals: the horizontal-vertical illusion (HVI). Under various contextual conditions, the HVI was as small as 3% (horizontals had to be 3% greater than verticals to be perceived as equally long) and as great as 15%, equaling about 12% in a "neutral" context. In Experiment 6, subjects judged the absolute physical length of each stimulus, and the results indicated that stimulus context acted largely by decreasing perceived lengths. The results are consistent with the hypothesis that differential effects of context reflect a process of stimulus-specific perceptual attenuation.
实验1至5采用配对比较法，结果表明，当刺激组包含相对较长的水平线和较短的垂直线时，判断给定垂直线比给定水平线长的概率相对较高；而当刺激组包含较短的水平线和较长的垂直线时，该概率相对较低。就刺激情境对感知长度产生方向特异性影响而言，它由此调节了垂直线比物理上等效的水平线看起来更长的程度，即水平-垂直错觉（HVI）。在各种情境条件下，HVI小至3%（水平线必须比垂直线长3%才能被感知为等长），大至15%，在“中性”情境中约为12%。在实验6中，受试者判断每个刺激的绝对物理长度，结果表明刺激情境主要通过缩短感知长度起作用。这些结果与以下假设一致，即情境的差异效应反映了特定刺激的感知衰减过程。
