Is optic flow used to guide walking while wearing a displacing prism?
Is optic flow used to guide walking while wearing a displacing prism?
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DOI：
10.1068/p3160
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发表时间：
2001-01-01
期刊：
影响因子：
1.7
通讯作者：
Carré, G
中科院分区：
文献类型：
--
作者：
Harris, MG;Carré, G
Rushton等人（1998年《当代生物学》，第8卷，第1191 - 1194页）最近表明，佩戴位移棱镜的步行者遵循由其目标的感知方向确定的弯曲轨迹。这表明光流在引导中并不重要，因为流线索不受棱镜的影响，并且应该允许直的、直接的轨迹。我们重复了Rushton等人的结果，但也试图排除与棱镜相关的重要伪影。棱镜限制了视野，特别是限制了对前景光流的访问，前景光流在提供引导线索中可能是重要的。我们发现，当步行者将他们的目光指向包括前景流时，性能并没有改善，这表明Rushton等人的结果不是由于这种伪影。另一方面，当受试者通过向目标爬行来降低观察高度时，表现确实可靠地提高了。这种改进可能是由于视觉纹理的粗糙化或对齐和运动视差线索的显著性增加。无论其原因是什么，这种改进表明，制导不仅仅取决于感知的目标方向，而且在某些情况下，流可能很重要。
Rushton et al (1998 Current Biology 8 1191 - 1194) recently showed that walkers wearing displacing prisms follow curved trajectories determined by the perceived direction of their target. This suggests that optic flow is not important in guidance, since flow cues are unaffected by the prism and should allow a straight, direct trajectory. We replicated Rushton et al's result but also tried to rule out an important artifact associated with the prism. Prisms restrict the field of view and, particularly, access to the foreground optic flow that is likely to be important in providing guidance cues. We found that performance did not improve when walkers directed their gaze to include the foreground flow, suggesting that Rushton et al's results were not due to this artifact. On the other hand, performance did reliably improve when subjects reduced their viewing height by crawling towards the target. This improvement may be due to coarsening of the visual texture or to increased salience of alignment and motion-parallax cues. Whatever its cause, the improvement demonstrates that guidance is not determined only by perceived target direction and that, under some conditions, flow may be important.