Department of Psychology, University of Nevada Reno Reno, NV, USA.
Front Hum Neurosci. 2015 Feb 18;9:77. doi: 10.3389/fnhum.2015.00077. eCollection 2015.
The Ebbinghaus illusion is a classic example of the influence of a contextual surround on the perceived size of an object. Here, we introduce a novel variant of this illusion called the Dynamic Ebbinghaus illusion in which the size and eccentricity of the surrounding inducers modulates dynamically over time. Under these conditions, the size of the central circle is perceived to change in opposition with the size of the inducers. Interestingly, this illusory effect is relatively weak when participants are fixating a stationary central target, less than half the magnitude of the classic static illusion. However, when the entire stimulus translates in space requiring a smooth pursuit eye movement to track the target, the illusory effect is greatly enhanced, almost twice the magnitude of the classic static illusion. A variety of manipulations including target motion, peripheral viewing, and smooth pursuit eye movements all lead to dramatic illusory effects, with the largest effect nearly four times the strength of the classic static illusion. We interpret these results in light of the fact that motion-related manipulations lead to uncertainty in the image size representation of the target, specifically due to added noise at the level of the retinal input. We propose that the neural circuits integrating visual cues for size perception, such as retinal image size, perceived distance, and various contextual factors, weight each cue according to the level of noise or uncertainty in their neural representation. Thus, more weight is given to the influence of contextual information in deriving perceived size in the presence of stimulus and eye motion. Biologically plausible models of size perception should be able to account for the reweighting of different visual cues under varying levels of certainty.
艾宾浩斯错觉是上下文环境对物体感知大小产生影响的经典范例。在这里，我们引入了这种错觉的一种新变体，称为动态艾宾浩斯错觉，其中周围诱导物的大小和离心率随时间动态变化。在这些条件下，中央圆的大小被感知为与诱导物的大小相反变化。有趣的是，当参与者注视静止的中央目标时，这种错觉效应相对较弱，不到经典静态错觉的一半。然而，当整个刺激在空间中平移，需要平滑追踪眼球运动来跟踪目标时，错觉效应大大增强，几乎是经典静态错觉的两倍。各种操作，包括目标运动、周边观察和平滑追踪眼球运动，都会产生显著的错觉效应，最大效应几乎是经典静态错觉的四倍。我们根据运动相关操作会导致目标图像大小表示的不确定性这一事实来解释这些结果，特别是由于视网膜输入层面增加了噪声。我们提出，整合大小感知视觉线索的神经回路，如视网膜图像大小、感知距离和各种上下文因素，会根据其神经表示的噪声或不确定性水平，对每个线索进行加权。因此，在存在刺激和眼球运动的情况下，会更多地考虑上下文信息对感知大小的影响。具有生物合理性的大小感知模型应该能够解释在不同确定性水平下不同视觉线索的重新加权。
