Calibration of peripheral perception of shape with and without saccadic eye movements

Abstract

The cortical representations of a visual object differ radically across saccades. Several studies claim that the visual system adapts the peripheral percept to better match the subsequent foveal view. Recently, Herwig, Weiß, and Schneider (2015, Annals of the New York Academy of Sciences, 1339(1), 97-105) found that the perception of shape demonstrates a saccade-dependent learning effect. Here, we ask whether this learning actually requires saccades. We replicated Herwig et al.'s (2015) study and introduced a fixation condition. In a learning phase, participants were exposed to objects whose shape systematically changed during a saccade, or during a displacement from peripheral to foveal vision (without a saccade). In a subsequent test, objects were perceived as less (more) curved if they previously changed from more circular (triangular) in the periphery to more triangular (circular) in the fovea. Importantly, this pattern was seen both with and without saccades. We then tested whether a variable delay between the presentations of the peripheral and foveal objects would affect their association-hypothetically weakening it at longer delays. Again, we found that shape judgments depended on the changes experienced during the learning phase and that they were similar in both the saccade and fixation conditions. Surprisingly, they were not affected by the delay between the peripheral and foveal presentations over the range we tested. These results suggest that a general associative process, independent of saccade execution, contributes to the perception of shape across viewpoints.

Trans-saccadic adaptation of perceived size independent of saccadic adaptation

“…The observed modification of size perception was in line with several studies that demonstrated an interaction between the motor adaptation with a distortion of visual localization of the target executed by hand pointing or by perceptual reports (Awater, Burr, Lappe, Morrone, & Goldberg, 2005;Bahcall & Kowler, 1999;Bruno & Morrone, 2007;Collins, Doré-Mazars, & Lappe, 2007;Garaas & Pomplun, 2011;Gremmler, Bosco, Fattori, & Lappe, 2014;Zimmermann & Lappe, 2010). Several more recent studies have indicated that adaptation of visual features can be found without saccadic adaptation (Herwig & Schneider, 2014;Herwig, Weiß, & Schneider, 2015;Herwig, Weiß, & Schneider, 2018;Köller, Poth, & Herwig, 2020;Paeye, Collins, Cavanagh, & Herwig, 2018;Valsecchi & Gegenfurtner, 2016;Valsecchi, Cassanello, Herwig, Rolfs, & Gegenfurtner, 2020). Specifically, features for which this phenomenon occurs are spatial frequency (Herwig & Schneider, 2014;Herwig et al, 2018), shape (Herwig et al, 2015;Köller et al, 2020;Paeye et al, 2018) and size (Bosco et al, 2015;Valsecchi & Gegenfurtner, 2016;Valsecchi et al, 2020).…”

“…Several more recent studies have indicated that adaptation of visual features can be found without saccadic adaptation (Herwig & Schneider, 2014;Herwig, Weiß, & Schneider, 2015;Herwig, Weiß, & Schneider, 2018;Köller, Poth, & Herwig, 2020;Paeye, Collins, Cavanagh, & Herwig, 2018;Valsecchi & Gegenfurtner, 2016;Valsecchi, Cassanello, Herwig, Rolfs, & Gegenfurtner, 2020). Specifically, features for which this phenomenon occurs are spatial frequency (Herwig & Schneider, 2014;Herwig et al, 2018), shape (Herwig et al, 2015;Köller et al, 2020;Paeye et al, 2018) and size (Bosco et al, 2015;Valsecchi & Gegenfurtner, 2016;Valsecchi et al, 2020). Particular focus has to be given to these two latter studies that tested paradigms able to demonstrate a size recalibration independent of saccade adaptation.…”

Eye movements shape visual learning

“…These studies for the most part have involved training and testing during fixation in the absence of eye movements. One exception is the learning of new visual associations between stimuli seen across saccades (40)(41)(42)(43), but in most cases it does not appear that saccades are necessary to elicit this type of learning (39)(40)(41). Other studies have shown that perceptual learning is sensitive to spatiotopic locations defined in part by eye position (44) and that perceptual learning can improve visual sensitivity during saccades (45).…”

A comparison of the temporal and spatial properties of trans-saccadic perceptual recalibration and saccadic adaptation

“…The calibration of peripheral and central perceived appearance is a phenomenon that seems to exist at the boundary of two domains (Herwig, 2015a). On the one hand, it is a perceptual phenomenon, which can be both acquired and expressed without eye movements (Paeye et al, 2018;Valsecchi & Gegenfurtner, 2016). However, this form of calibration should take place most commonly due to trans-saccadic feedback.…”