Radboud University, Donders Institute for Brain, Cognition and Behaviour, The Netherlands.
CIMeC, University of Trento, Italy.
J Vis. 2021 Jul 6;21(7):12. doi: 10.1167/jov.21.7.12.
A key feature of visual processing in humans is the use of saccadic eye movements to look around the environment. Saccades are typically used to bring relevant information, which is glimpsed with extrafoveal vision, into the high-resolution fovea for further processing. With the exception of some unusual circumstances, such as the first fixation when walking into a room, our saccades are mainly guided based on this extrafoveal preview. In contrast, the majority of experimental studies in vision science have investigated "passive" behavioral and neural responses to suddenly appearing and often temporally or spatially unpredictable stimuli. As reviewed here, a growing number of studies have investigated visual processing of objects under more natural viewing conditions in which observers move their eyes to a stationary stimulus, visible previously in extrafoveal vision, during each trial. These studies demonstrate that the extrafoveal preview has a profound influence on visual processing of objects, both for behavior and neural activity. Starting from the preview effect in reading research we follow subsequent developments in vision research more generally and finally argue that taking such evidence seriously leads to a reconceptualization of the nature of human visual perception that incorporates the strong influence of prediction and action on sensory processing. We review theoretical perspectives on visual perception under naturalistic viewing conditions, including theories of active vision, active sensing, and sampling. Although the extrafoveal preview paradigm has already provided useful information about the timing of, and potential mechanisms for, the close interaction of the oculomotor and visual systems while reading and in natural scenes, the findings thus far also raise many new questions for future research.
人类视觉处理的一个关键特征是使用眼跳（saccadic eye movements）来环顾周围的环境。眼跳通常用于将相关信息（通过周边视觉瞥见）带入高分辨率的中央凹（fovea）进行进一步处理。除了一些特殊情况，例如走进房间时的第一次注视，我们的眼跳主要是基于这种周边视觉预览来引导的。相比之下，视觉科学的大多数实验研究都调查了对突然出现且通常在时间或空间上不可预测的刺激的“被动”行为和神经反应。如这里所回顾的，越来越多的研究调查了在观察者在每次试验中移动眼睛以注视先前在周边视觉中可见的静止刺激的更自然的观看条件下，物体的视觉处理。这些研究表明，周边视觉预览对物体的视觉处理有深远的影响，无论是对行为还是神经活动。从阅读研究中的预览效应开始，我们跟随更广泛的视觉研究的后续发展，最终认为，认真对待这些证据会导致重新概念化人类视觉感知的本质，即将预测和行动对感觉处理的强烈影响纳入其中。我们回顾了自然观看条件下视觉感知的理论观点，包括主动视觉、主动感知和采样理论。虽然周边视觉预览范式已经提供了有关阅读和自然场景中眼球运动和视觉系统紧密相互作用的时间和潜在机制的有用信息，但迄今为止的发现也为未来的研究提出了许多新的问题。
