Journal of Illusion

Perceptual filling-in of the blind spot using surrounding filled-in information

2026-01-12T07:30:25+00:00

We showed a novel visual illusion of filling-in occurring at the blind spot. We tried to see what is perceived in the blind spot when its surrounding visual information perceptually faded. It was found that when the surrounding itself perceptually disappeared under three cases of perceptual fading phenomena (transient-induced fading, contrast decrement disappearance, and Troxler fading), the blind spot was perceptually filled-in by information outside its immediate surround. Three movies are supplied to demonstrate the illusory phenomena.

Three-dot misalignment illusion and related new illusions: a rediscovery of Bouma and Andriessen’s (1968) oblique effect as a strong illusion

2026-01-20T07:36:36+00:00

We describe a misalignment illusion observed in the spatial arrangement of three collinear dots, where two dots are proximally positioned while the third is distally located. The illusion manifests when the dots are oriented obliquely, creating a perceived deviation from linear alignment. In a near-vertical configuration with slight clockwise orientation, the extrapolated line connecting the proximal dots appears to pass laterally left of the superior distal dot. Conversely, in a near-horizontal arrangement with counterclockwise orientation, the perceived line trajectory falls inferior to the rightward distal dot. The illusion’s magnitude exhibits distance-dependency: it is absent when all three dots are equidistant but intensifies as the distance between the pair of dots and the remaining dot increases. While we independently discovered this perceptual phenomenon, subsequent literature review revealed its correspondence with the findings reported by Bouma and Andriessen (1968). Although historically categorized as tilt normalization or an oblique effect, we propose reconceptualizing this Bouma–Andriessen phenomenon as a distinct and robust misalignment illusion. Furthermore, we demonstrate that this illusion emerges even with abstract geometric features, such as circle centres or rectangle corners.

Variations and extensions of the kinetic Orbison illusion

2025-06-14T03:27:32+00:00

When a dot moves along a square trajectory on concentric circles, the trajectory appears to bend toward the center of the circles (the kinetic Orbison illusion). This report demonstrates new illusions that are variations or extensions of the kinetic Orbison illusion. We found that some of them produced an illusory effect that was larger than the original version of the kinetic Orbison illusion (up to 1.8 times larger than the original). The illusion became even stronger when a dot moved along a triangular trajectory, reaching 1.4 times the strength as that of the strongest illusion with the square trajectory. The implications of these illusions for the kinetic Orbison illusion and the relationship to previously reported motion illusions are discussed.

Perpetual rotation of real and illusory shapes

2025-03-27T10:03:30+00:00

The field of perceptual psychology has long been interested in determining how the perception of global shape arises from the interplay between local elements. We investigate this issue by combining the Kanizsa square illusion (an illusory square that emerges from the placement of four Pacman-like shapes) with edge motion illusions (the illusory continuous motion perceived when the luminance of a stationary edge and neighboring fields is modulated in time). Our basic demonstration builds on cascading levels of motion signals: illusory motion at a point is known to be ambiguous as to direction (the aperture problem); illusory motion of edges in isolation (here, the local elements) is perceived as either vertical or horizontal; illusory motion of edges when combined at right angles is perceived as diagonal; and illusory motion of the Kanizsa square (the global percept) is perceived as rotational. The perception of a rotating square suggests that the interpretation of the local motion signals depends on the global context and is, perhaps, informed by a tendency to perceive shapes as rigid. We created variants of the original figure to identify and assess critical factors of this phenomenon, including changes in temporal phase and amodal completion of motion. Our investigations with the basic figure and variants – examples of multistable motion illusions – demonstrate that observers can easily switch their attention between perceptual modes constructed separately from the local and global motion information.