A New Motion Illusion Related to the Aperture Problem

Abstract

A previously unreported motion illusion is described. Oblique lines that drift smoothly on the retina in a vertical direction appear to be displaced laterally. The effect occurs both for moving lines under fixation and for stationary lines under ocular tracking of an external target. Orientation, length, and homogeneity of the obliques affect the magnitude of illusory displacement. We propose that this illusion is associated with a misregistration of the direction of displacement occurring, in lines slanted relative to the axis of their motion, because of the aperture problem.

Treacherous Pavements: Paving Slab Patterns Modify Intended Walking Directions

“…With a pattern of results consistent with those of Bressan and Vezzani’s visual motion illusion [13], we found that participants veered substantially away from straight ahead when walking over a patterned floor with oblique pattern orientations. We propose that the veering observed here is due to the aperture problem in motion perception [11] in the relatively restricted lower visual field, leading people to misperceive their own lateral location in space while traversing the walkway.…”

“…In the human visual system, the aperture problem occurs whenever the detection of motion is carried out over a limited part of a scene such as in the lower visual field inherent for floor patterns. The effect can be easily visualised with a compelling motion illusion first described by Bressan and Vezzani [13]. In this illusion, visually tracking a dot that moves vertically between two stationary oblique lines makes the lines appear to move laterally.…”

“…Using paving slab patterns similar to those seen on pavements, we investigated whether the walking-induced moving contours, formed by the tile shape and the grouting between the tiles or slabs, created a similar illusion to that described by Bressan and Vezzani [13], thus affecting people’s walking direction in an obstacle free environment. Note that pavement slab patterns contain basic single-component orientations (SCO) (see Fig 1b, orientation directions indicated by red and yellow arrows), consisting of high-luminance contrast lines (i.e.…”

Motion Capture Depends Upon the Common Fate Factor Among Elements

“…The motion illusion in terms of oblique lines has been employed in different studies, such as for measuring the receptive field size of the motion detector, which underlie the aperture problem in motion perception , and for investigating the relationship between the magnocellular-dorsal stream and dyslexia (Gori et al, 2015). These motion illusions are based on the detection of illusory motion signals in viewing the oblique components, which drift smoothly on the retina (Bressan & Vezzani, 1995;Gori & Hamburger, 2006). Results of several studies have indicated that the processing of oblique components underlies motion illusions of different types, not only the Pinna illusion (Ichikawa et al, 2006;Pinna & Brelstaff, 2000) but also the Ouchi-Spillman illusion (Ashida, 2002;Fermu¨ller, Pless, & Aloimonos, 2000;Mather, 2000;Ouchi, 1977;Spillmann, 2013), Rotating-Tilted-Line illusion , Unchained-dot illusion (Gori, Giora, & Stubbs, 2010), illusion of direction for the moving matrices of oblique lines (Lorenceau, Shiffrar, Wells, & Castet, 1993), and nonrigid motion illusion with nonparallel oblique components (Kim & Papathomas, 2011).…”

Illusory Object Motion in the Centre of a Radial Pattern: The Pursuit-Pursuing Illusion

“…The effects in almost all of the motion illusions caused by smooth retinal motion depend on the angles between the retinal motion direction and the detected motion direction (Bressan and Vezzani 1995; Fantoni and Pinna 2008; Gori and Yazdanbakhsh 2008; Ito et al 2009; Pinna and Brelstaff 2000). Some depend on the angles between the retinal motion direction and the orientation of the stimulus elements, eg, parallel (Khang and Essock 2000) or orthogonal (Pinna and Spillmann 2005, figure 9; Ito et al 2009, figure 5).…”