ABSTRACT

Computational models of motion perception suggest that the perceived direction of weak motion signals may sometimes be directly opposite to the true stimulus motion direction. However, this possibility cannot be assessed by using standard 2AFC motion discrimination paradigms because two opposite directions of motion were used in most studies (e.g., leftward vs. rightward). We were able to obtain robust evidence of opposite-direction motion reports by using a random-dot-kinematogram (RDK) paradigm in which the motion direction varied over 360° and observers were asked to estimate the exact motion direction. These opposite-direction motion reports were replicable across multiple display types and feedback conditions, and observers had greater confidence in their opposite-direction responses than in true guess responses. When we fed RDKs into a computational model of motion processing, we found that the model estimated substantial motion activity in the direction opposite to the coherent stimulus direction, even though no such motion was objectively present in the stimuli, suggesting that the opposite-direction motion perception may be a consequence of the properties of motion-selective neurons in visual cortex. Together, these results demonstrate that the known properties of the visual system may lead to reports of motion that are directly opposite to the true direction.

摘要

运动感知的计算模型表明，弱运动信号的感知方向有时可能与真实刺激运动方向直接相反。然而，这种可能性不能通过使用标准的 2AFC 运动辨别范式来评估，因为在大多数研究中使用了两个相反的运动方向（例如，向左与向右）。我们能够通过使用随机点运动图 (RDK) 范例获得相反方向运动报告的有力证据，其中运动方向在 360° 范围内变化，并要求观察者估计确切的运动方向。这些相反方向的运动报告可在多种显示类型和反馈条件下复制，与真实的猜测反应相比，观察者对他们的相反方向反应更有信心。当我们将 RDK 馈入运动处理的计算模型时，我们发现该模型估计了与相干刺激方向相反的方向的大量运动活动，即使刺激中没有客观存在这样的运动，这表明相反方向的运动感知可能是视觉皮层中运动选择性神经元特性的结果。总之，这些结果表明，视觉系统的已知特性可能导致报告与真实方向直接相反的运动。表明相反方向的运动感知可能是视觉皮层中运动选择性神经元特性的结果。总之，这些结果表明，视觉系统的已知特性可能导致报告与真实方向直接相反的运动。表明相反方向的运动感知可能是视觉皮层中运动选择性神经元特性的结果。总之，这些结果表明，视觉系统的已知特性可能导致报告与真实方向直接相反的运动。