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首页> 外文期刊>Vision Research: An International Journal in Visual Science >Contrast dependency and prior expectations in human speed perception
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Contrast dependency and prior expectations in human speed perception

机译：人体速度感知中的对比依赖性和先前期望

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摘要

The perceived speed of moving objects has long been known to depend on image contrast. Lowering the contrast of first-order motion stimuli typically decreases perceived speed - the well-known "Thompson effect". It has been suggested that contrast-dependent biases are the result of optimal inference by the visual system, whereby unreliable sensory information is combined with prior beliefs. The Thompson effect is thought to result from the prior belief that objects move slowly (in Bayesian terminology, a "slow speed prior"). However, there is some evidence that the Thompson effect is attenuated or even reversed at higher speeds. Does the effect of contrast on perceived speed depend on absolute speed and what does this imply for Bayesian models with a slow speed prior? We asked subjects to compare the speeds of simultaneously presented drifting gratings of different contrasts. At low contrasts (3-15%), we found that the Thompson effect was attenuated at high speeds: at 8 and 12 deg/s, perceived speed increased less with contrast than at 1 and 4 deg/s; however, at higher contrasts (15-95%), the situation was reversed. A semi-parametric Bayesian model was used to extract the subjects' speed priors and was subsequently improved by combining it with a model of speed tuning. These novel findings regarding the dual, contrast-dependent effect of high speeds help reconcile existing conflicting literature and suggest that physiologically plausible mechanisms of representation of speed in the visual cortex may need to be incorporated into Bayesian models to account for certain subtleties of human speed perception.
机译：早就知道移动物体的感知速度取决于图像对比度。降低一阶运动刺激的对比度通常会降低感知速度-众所周知的“汤普森效应”。已经提出，依赖对比度的偏差是视觉系统最佳推断的结果，由此不可靠的感觉信息与先前的信念相结合。汤普森效应被认为是由于先验的认为物体运动缓慢而产生的（在贝叶斯术语中，是“慢速先验”）。但是，有证据表明，汤普森效应在较高的速度下会减弱甚至逆转。对比度对感知速度的影响是否取决于绝对速度，这对于先验速度较慢的贝叶斯模型意味着什么？我们要求受试者比较同时呈现的具有不同对比度的漂移光栅的速度。在低对比度（3-15％）下，我们发现汤普森效应在高速下减弱：在8和12度/秒时，感知速度与对比度相比增加的幅度小于在1和4度/秒时;但是，在更高的对比度（15-95％）下，情况则相反。使用半参数贝叶斯模型来提取受试者的先验速度，随后通过将其与速度调整模型结合来进行改进。这些有关高速的双重，依赖于对比度的效应的新颖发现有助于调和现有的矛盾文献，并提出可能需要将视觉上皮层速度的生理学合理表达机制纳入贝叶斯模型中，以说明人类对速度感知的某些微妙之处。 。

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