The extrafoveal preview paradigm as a measure of predictive, active sampling in visual perception

Abstract

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.

Familiar objects benefit more from transsaccadic feature predictions

“…Each sacdirected to an object provides peripheral information and foveal information about the targeted object. The visual system uses the available sensory information to make transsaccadic predictions about how an object would look like in different viewing conditions (e.g., Herwig & Schneider, 2014; for reviews, see Huber-Huber et al, 2021;Stewart et al, 2020).…”

Retinotopic organization of feedback projections in primate early visual cortex: implications for active vision

“…There is considerable evidence that motor signals are fed back into the sensory processing (Merriam and Colby, 2005). An equivalent sensorimotor coupling reported in mouse visual cortex in the primate could involve the coupling of foveal and extrafoveal processing via saccadic eye movements, allowing natural vision to be conceived as an active sensing of the environment (Ahissar and Assa, 2016; Gallant et al, 1998; Huber-Huber et al, 2021; Ito et al, 2022; Schroeder et al, 2010). In the framework of active sensing, top-down influences on the peripheral representation of the early visual areas can be related to modulation of excitability and stimulus evoked activity to a peripheral target (Barczak et al, 2019).…”

Current foveal inspection and previous peripheral preview influence subsequent eye movement decisions

“…The present differences in drift rate and non-decision time further depended on whether the inspection target could be previewed with the periphery: peripheral preview decreased non-decision times and modulated the increase in drift rates. These reduced non-decision times can be considered a further example of the well-established peripheral preview benefit: better or faster processing of foveated objects that had been previewed in the periphery prior to the saccade (for review see Huber-Huber et al., 2021 ). Yet, we cannot ultimately distinguish whether fixation durations and non-decision times decreased due to the peripheral preview or whether they increased in the outline condition due to a trans-saccadic prediction error.…”