Opposite effects of motion dynamics on the Ebbinghaus and corridor illusions

Abstract

We recently showed that motion dynamics greatly enhance the magnitude of certain size contrast illusions, such as the Ebbinghaus and Delboeuf illusions. Here, we extend our study of the effect of motion dynamics on size illusions through a novel dynamic corridor illusion, in which a single target translates along a corridor background. Across three psychophysical experiments, we quantify the effects of stimulus dynamics on the Ebbinghaus and corridor illusions across different viewing conditions. The results revealed that stimulus dynamics had opposite effects on these different classes of size illusions. Whereas dynamic motion enhanced the magnitude of the Ebbinghaus illusion, it attenuated the magnitude the corridor illusion. Our results highlight precision-driven weighting of visual cues by neural circuits computing perceived object size. This hypothesis is consistent with observations beyond size perception and may represent a more general principle of cue integration in the visual system. Keywords Visual perception . Perceptual organization . Bayesian modeling An object's perceived size arises from the interaction and integration of the angular size of the object (as projected on the retina) with numerous contextual cues. Most relevant to the current study, these cues include physical and perceived dis-

Dynamic presentation boosts the Ebbinghaus illusion but reduces the Müller-Lyer and orientation contrast illusions

“…This explanation clearly no longer holds. Dynamic versions of the corridor illusion (Mruczek et al, 2020a) and the Ponzo illusion actually decrease (Mruczek et al, 2020b), as we also found here for the orientation contrast and Müller-Lyer illusions. We chose the orientation contrast and Müller-Lyer illusions for our tests here because they are not size contrast effects like the original dynamic Ebbinghaus illusion.…”

“…Here, we further explored the effect of dynamic versions on illusions where size contrast is not involved: simultaneous contrast and Müller-Lyer. To anticipate the results, like Mruczek and colleagues (2020a , 2020b ), we find no evidence that other illusions increase in magnitude when set in motion. The Ebbinghaus illusion itself is a type of simultaneous contrast in size so we first tested simultaneous brightness contrast ( Heinemann, 1955 ) and orientation contrast illusions ( Westheimer, 1990 ).…”

“…Similarly, the motion induced in a stationary spot by a moving frame ( Duncker, 1929 ) also increases by an order of magnitude when the spot itself moves orthogonally to the frame ( Wallach, Bacon, & Schulman, 1978 ). However, most other illusions are reduced when presented in motion (the corridor illusion; Mruczek et al, 2020a , the Müller-Lyer illusion here) or even eliminated (as the orientation contrast here). Further investigations are warranted to clarify determining factors of differential effect of dynamic presentation on visual illusions.…”

“…For the Ebbinghaus illusion, the illusion was enhanced when the inducer size was modulated in synchrony with a continuous displacement of the stimulus (Dynamic Ebbinghaus illusion: Mruczek et al, 2015 ). Motivated by their studies (e.g., Mruczek et al, 2015 ; Mruczek et al, 2020a ; Mruczek et al, 2020b ), we tested the effect dynamic presentation on other illusions: first replicating the Ebbinghaus condition, then adding the orientation contrast and Müller-Lyer illusions.…”

“…However, when the configuration was in motion, the accumulation no longer built up locally and therefore the illusion magnitude could increase with fewer restraints. Recently, they reported that the dynamic version of the corridor illusion showed an effect opposite to that of the Ebbinghaus illusion, decreasing in magnitude in the dynamic version ( Mruczek, Blair, Cullen & Caplovitz, 2020a ). They also investigated whether a dynamic presentation increased the Ponzo illusion but found little effect ( Mruczek, Kelly, Sagona, Fanelli & Caplovitz, 2020b ).…”