Gekas Nikos, Mamassian Pascal
Department of Psychology, Edinburgh Napier University, Edinburgh, UK.
School of Psychology, University of Nottingham, Nottingham, UK.
J Vis. 2025 Jan 2;25(1):10. doi: 10.1167/jov.25.1.10.
Visual perception has been described as a dynamic process where incoming visual information is combined with what has been seen before to form the current percept. Such a process can result in multiple visual aftereffects that can be attractive toward or repulsive away from past visual stimulation. A lot of research has been conducted on what functional role the mechanisms that produce these aftereffects may play. However, there is a lack of understanding of the role of stimulus uncertainty on these aftereffects. In this study, we investigate how the contrast of a stimulus affects the serial aftereffects it induces and how the stimulus itself is affected by these effects depending on its contrast. We presented human observers with a series of Gabor patches and monitored how the perceived orientation of stimuli changed over time with the systematic manipulation of orientation and contrast of presented stimuli. We hypothesized that repulsive serial effects would be stronger for the judgment of high-contrast than low-contrast stimuli, but the other way around for attractive serial effects. Our experimental findings confirm such a strong interaction between contrast and sign of aftereffects. We present a Bayesian model observer that can explain this interaction based on two principles, the dynamic changes of orientation-tuned channels in short timescales and the slow integration of prior information over long timescales. Our findings have strong implications for our understanding of orientation perception and can inspire further work on the identification of its neural mechanisms.
视觉感知被描述为一个动态过程，在这个过程中，传入的视觉信息与之前所看到的信息相结合，形成当前的感知。这样的过程会导致多种视觉后效，这些后效可能会吸引或排斥过去的视觉刺激。关于产生这些后效的机制可能发挥的功能作用，已经进行了大量研究。然而，对于刺激不确定性在这些后效中的作用，人们还缺乏了解。在本研究中，我们探究了刺激的对比度如何影响其所诱发的序列后效，以及刺激本身如何根据其对比度受到这些效应的影响。我们向人类观察者呈现一系列Gabor斑块，并通过系统地操纵所呈现刺激的方向和对比度，监测刺激的感知方向随时间如何变化。我们假设，对于高对比度刺激的判断，排斥性序列效应会比低对比度刺激更强，但对于吸引性序列效应则相反。我们的实验结果证实了对比度和后效符号之间存在如此强烈的相互作用。我们提出了一个贝叶斯模型观察者，它可以基于两个原则来解释这种相互作用，即在短时间尺度上方向调谐通道的动态变化以及在长时间尺度上先验信息的缓慢整合。我们的研究结果对我们理解方向感知具有重要意义，并能激发关于其神经机制识别的进一步研究。
