Dominant right hemisphere controls biased rotation perception.

Abstract

Bistable perception is a form of visual illusion that is widely used in the context of brain research. The spinning dancer illusion is a form of bistable perception that can be used to study the perception of motion and rotation. However, the underlying mechanism of such bistability is not fully understood. To determine the possible mechanisms involved, psychophysical methods may provide valuable tools. In the present study, we investigated the effects of stimulus position in the visual field on the duration and number of perceptual reversals in the spinning dancer task. The results indicated that the duration of counterclockwise perception was significantly shorter when the stimulus was presented in the left hemifield compared with the right hemifield (p Ͻ .01). Neural adaptation in the right hemisphere might play a role in shortening the duration of counterclockwise perception in left hemifield trials. We suggest that the usual optical flow can explain the basic clockwise tendency of the right hemisphere in rotation perception. Our results are consistent with previous functional MRI studies, supporting the hypothesis that right hemisphere dominance in motion perception causes a bias toward clockwise perception in the spinning dancer task.

Hemifield-Specific Rotational Biases during the Observation of Ambiguous Human Silhouettes

“…Moreover, a larger number of figures were interpreted as spinning CW in the LVF than in the RVF (corresponding to the fact that participants interpreted a larger number of figures as right-limbed in the RVF rather than in the LVF in the inward-rotation condition, and a larger number of figures as right-limbed in the LVF rather than in the RVF in the outward-rotation condition). These results are consistent with those reported by Alipour and Kazemi [24], who found analogous effects by presenting the spinning dancer illusion in the two hemifields. With the exception of that study, no previous research examined the effects of eccentricity on the perception of the spinning direction of bistable stimuli.…”

“…However, there is some evidence suggesting that the hemifield of presentation might also affect the perceived spinning direction of ambiguous stimuli for other, non-motoric, reasons. In particular, as already proposed by [24], the usual experience of optic flow (i.e., the motion patterns of objects in the visual field of the observer; [25,26]) could induce hemispheric-specific rotational biases when one observes rotating objects with an ambiguous spinning direction. Indeed, the experience of optic flow (which occurs during walking, running, driving, and other activities implying a forward motion) is represented by the constant movement of objects "toward" the observer, but is also analogous to the perception of the motion vectors on the visible surface of a cylinder rotating CW (clockwise) in the LVF, and of those on the visible surface of a cylinder rotating CCW (counterclockwise) in the RVF.…”

“…Indeed, the experience of optic flow (which occurs during walking, running, driving, and other activities implying a forward motion) is represented by the constant movement of objects "toward" the observer, but is also analogous to the perception of the motion vectors on the visible surface of a cylinder rotating CW (clockwise) in the LVF, and of those on the visible surface of a cylinder rotating CCW (counterclockwise) in the RVF. Specifically, Alipour and Kazemi [24] found a significantly shorter duration of the CCW perception when a stimulus (the spinning dancer designed by Japanese web artist Nobuyuki Kayahara; http://www.procreo.jp/labo/labo13.html, accessed on 28 June 2021) was presented in the LVF rather than in the RVF. Moreover, Burton et al [27] examined reaction times for CW and CCW mental rotations in the two hemifields, showing that CCW and CW rotations were more efficiently performed in the RVF and LVF, respectively.…”

Precision Weighted Inference in Bistable Perception? Investigations into an Effect of Visual Field Location on Primed Awareness

“…Asymmetrical biases like these have also been reported in the perception of bistable motion stimuli. Both Alipour & Kazemi (2015) and Lucafò et al (2021) demonstrated that ambiguously rotating human silhouettes are more likely to be perceived as rotating clockwise when presented to the left visual field. Researchers in both studies suggested that processes underlying optic flow (the movement of objects across the visual field during forwards locomotion) may help to explain this result however, no corresponding bias for counterclockwise rotation was found for the right visual field in either study and, furthermore, it is unknown whether this effect generalises to other similar motion animations (e.g.…”

“…However, the aims of these studies were never directed at understanding the influence of spatial differences on priors and their effect on awareness. Rather, they were focussed on other interesting phenomena such as hemispheric asymmetry (Alipour & Kazemi, 2015;Lucafò et al, 2021), idiosyncratic differences in spatial biases for higher order object categories (Afraz et al, 2010;Finlayson et al, 2020), and visual pattern persistence (Breitmeyer & Ritter, 1986;Rutherford, 2003).…”