Zanker J M, Harris J P
Department of Psychology, University of London, Royal Holloway, Egham, TW20 0EX, Surrey, UK.
Vision Res. 2002 Oct;42(22):2499-508. doi: 10.1016/s0042-6989(02)00301-2.
The spatial grain of the human visual system has always been a central topic for visual sciences, and the optical and physiological basis of perceptual limitations are well described. In particular, we have thorough accounts of spatial hyperacuity, which refers to a precision in the spatial localisation of stimulus contours that is better than the photoreceptor grain that determines spatial resolution. However, although the temporal resolution of the human visual system is comparably well described, we have almost no direct knowledge about the precision of localising visual stimuli in time in the absence of correlated spatial cues. The present study addresses this question by comparing directly the temporal resolution of human observers with their temporal acuity as measured in a temporal bisection task. Despite some improvement with practice, temporal acuity in this task does not fall below 20-30 ms in the best case, which is similar to the temporal resolution limit, and performance does not improve for comparison tasks with multiple stimulus presentations. The absence of visual hyperacuity for purely temporal modulations as tested here contrasts with processing limitations for other types of visual information in comparable tasks, and with other sensory modalities, in particular to those of the auditory system. Such differences can be interpreted in the context of the ecological requirements for organising behaviour, and the functional design of nervous systems.
人类视觉系统的空间粒度一直是视觉科学的核心主题，其感知局限性的光学和生理基础也得到了很好的描述。特别是，我们对空间超敏锐度有深入的了解，它指的是刺激轮廓空间定位的精度，优于决定空间分辨率的光感受器粒度。然而，尽管人类视觉系统的时间分辨率也得到了较好的描述，但在没有相关空间线索的情况下，我们几乎没有关于视觉刺激时间定位精度的直接知识。本研究通过直接比较人类观察者的时间分辨率与其在时间二等分任务中测量的时间敏锐度来解决这个问题。尽管通过练习有了一些提高，但在最佳情况下，该任务中的时间敏锐度不会低于20 - 30毫秒，这与时间分辨率极限相似，并且对于多个刺激呈现的比较任务，性能也没有提高。与在类似任务中对其他类型视觉信息的处理局限性以及其他感觉模态（特别是听觉系统）相比，这里测试的纯时间调制不存在视觉超敏锐度。这些差异可以在组织行为的生态要求以及神经系统的功能设计背景下进行解释。
