Dynamic Re-calibration of Perceived Size in Fovea and Periphery through Predictable Size Changes

Abstract

The same object produces quite distinct images in the cortical representation, depending on whether it is looked at foveally or with the periphery, yet some form of size constancy prevents us from experiencing objects inflating or deflating as we move our eyes. According to the prominent sensorimotor account of vision by O'Regan and Noë [1], we constantly learn to discount the predictable sensory effects of motor actions, such as the projection of a stimulus on a larger cortical area as it gets foveated. Although previous studies have shown that foveal and parafoveal inputs can be associated in visual memory [2, 3], trans-saccadic prediction error could in principle re-calibrate even the appearance of peripheral and foveal stimuli. Here we introduce a new paradigm that induces such changes in the relative appearance of peripheral and foveal stimuli when directly compared. Repeated exposure to a trans-saccadic change in size, though unnoticed by most observers, induced a substantial modification of perceived size that lasted at least 1 day. Prediction is not limited to the motor system but can also occur for the sensory effects of external events, such as stimulus motion. We show that perceptual re-calibration can occur in the absence of eye movements if the change in size occurs predictably while objects move across the visual field. Perceptual uniformity emerges due to the continuously updated prediction of foveal appearance based on peripheral appearance.

The Interaction Between Vision and Eye Movements

“…Adaptation also took place, even though much less, when the association between fovea and periphery was established through visual motion, without making eye movements. There was no reverse recalibration when changing the size of the stimulus that was in the fovea initially (Valsecchi & Gegenfurtner, 2016). These results show the importance of basic prediction mechanisms for visual perception.…”

“…It was clearly below the threshold for detecting such changes, as determined by separate measurements. Figure 6 shows that our manipulation did have an effect on the relative perceived size of the peripheral stimulus, before making the saccade (Valsecchi & Gegenfurtner, 2016). After 500 trials, the relative size of the peripheral discs changed by about 5% on average or half of the 10% physical size change.…”

“…Previous studies had shown that an association between foveal and peripheral representations is possible in visual memory (Cox, Meier, Oertelt, & DiCarlo, 2005;Herwig, Weiß, & Schneider, 2015;Weiß, Schneider, & Herwig, 2014). We performed experiments testing the idea that their relative appearance can also be changed (Valsecchi & Gegenfurtner, 2016). (Schwartz, 1977) that magnifies the foveal representation relative to the periphery.…”

“…On the next day, the two groups were reversed, and with it the perceptual effects reverse. After Valsecchi and Gegenfurtner (2016).…”

Previewing a face in the periphery reduces the fN170: Combined EEG and eye-tracking suggests two stages of trans-saccadic predictive processes

“…One source of visual stability may be the integration of pre- and post-saccadic visual information (Helmholtz, 1867; Melcher, 2011; Wurtz, 2008). Recent gaze-contingent experimental designs have revealed that orientation (Ganmor et al, 2015; Wolf and Schütz, 2015; Zimmermann et al, 2017), object size (Valsecchi and Gegenfurtner, 2016), visual motion (Fabius et al, 2016), and whole-object information (Castelhano and Pereira, 2017; Schut et al, 2016) are integrated across saccades in a statistically optimal fashion taking into account the relative reliability of pre-saccadic and post-saccadic input (Ganmor et al, 2015; Herwig, 2015; Wolf and Schütz, 2015). Nonetheless, the time-course of trans-saccadic perception and, in particular, the content of perception immediately after fixation-onset remain controversial (for review, Melcher and Morrone, 2015)…”