Wenderoth P, Johnstone S
Department of Psychology, University of Sydney, NSW, Australia.
Perception. 1988;17(2):165-76. doi: 10.1068/p170165.
Four experiments in which logarithmic intervals between 25 and 1600 ms were used for stimulus duration in tests for the tilt illusion are reported. It is demonstrated that the direct and the indirect tilt illusions both increase in magnitude inversely with length of stimulus presentation. The data suggest that whereas the direct effect peaks with a value of about +7 degrees at the shortest flash duration used (25 ms), peak indirect effects (of about +2 degrees) do not occur at this duration. In addition, whereas direct effects level out after 100 ms stimulus exposure times, to the usual magnitude obtained with long presentations (about +2 degrees), indirect effects reach their standard magnitude (-0.5 degrees to -1.0 degrees) later, at exposures of about 400 ms. Even at very short flash durations, a luminance square frame surrounding the illusion display reduces the indirect effect by two thirds of its magnitude but has no effect at all on the direct effect. It is suggested that direct effects arise early in visual processing, in area V1, where there are transient mechanisms and where corruption of orientation analysis by the inducing grating would occur prior to later, extrastriate, global analysis of the surrounding peripheral frame. Indirect effects, on the other hand, may arise later, along the sustained parvocellular colour-form pathway, where more global processing occurs and susceptibility to surrounding fields might be expected.
本文报告了四项实验，这些实验在倾斜错觉测试中使用了25至1600毫秒的对数间隔作为刺激持续时间。结果表明，直接倾斜错觉和间接倾斜错觉的大小均与刺激呈现时间长度成反比。数据表明，虽然直接效应在使用的最短闪光持续时间（25毫秒）时达到约+7度的峰值，但在此持续时间并未出现间接效应的峰值（约+2度）。此外，虽然直接效应在刺激暴露100毫秒后趋于平稳，达到长时间呈现时通常获得的大小（约+2度），但间接效应在约400毫秒的暴露时间后才达到其标准大小（-0.5度至-1.0度）。即使在非常短的闪光持续时间下，围绕错觉显示的亮度方形框架也会将间接效应降低其三分之二，但对直接效应完全没有影响。研究表明，直接效应在视觉处理的早期阶段，即V1区域产生，该区域存在瞬态机制，并且在对周围外周框架进行后期的纹外全局分析之前，诱导光栅会破坏方向分析。另一方面，间接效应可能在后期沿着持续的小细胞颜色-形状通路产生，在该通路中会进行更多的全局处理，并且可能预期对周围区域敏感。
