Dynamic tilt illusion induced by continuous contextual orientation alternations

Abstract

In the classic tilt illusion, the perceived orientation of a center patch is shifted away from its oriented context. Additionally, a stronger illusion effect is yielded when the center patch is simultaneously rather than asynchronously presented with a constant context for a shorter duration. However, little is known about the temporal characteristic of the tilt illusion in a reverse situation in which a constant center patch is presented throughout while the contexts change. Therefore, we continuously alternated two opposite-oriented contexts and manipulated alternate speeds to examine how the tilt illusion would build up as a function of dynamic contextual alternation. Our results revealed that dynamic alternations between leftward- and rightward-oriented contexts caused a static vertical grating at the center to apparently sway from side to side. More importantly, the apparent sway illusion was modulated by the alternate speed of the oriented contexts (up to 8-10 Hz); the quicker the alternation is, the faster and weaker the apparent sway is. Intriguingly, the temporal characteristic of the "dynamic tilt illusion" suggests that, under a varying environment, the suppressions from temporally adjacent surrounds would be chunked into discrete epochs before affecting our percept.

Looking more masculine among females: Spatial context modulates gender perception of face and biological motion

“…Another supportive evidence for this lateral inhibition mechanism was provided by our finding that the simultaneous contrast effect of gender was mediated by the temporal synchrony between the central and surrounding stimuli, as the introduction of a 500-ms temporal separation between them completely erased the simultaneous contrast effect. This echoes with previous studies on low-level features, which demonstrated a disappearance of the tilt illusion with a relatively long temporal gap (Corbett et al, 2009;Durant & Clifford, 2006;Yuan et al, 2017). It is probably because the surround suppression of neural activities lasts ~200 ms after the context disappears (Ishikawa et al, 2010;Shimegi et al, 2014).…”

“…The occurrence of the simultaneous contrast effect is largely due to feature‐selective inhibition of neurons responding to the central stimuli (McDonald et al, 2009). Take the tilt illusion as an example, the lateral inhibition mechanism repels the perceived orientation of a vertical centre grating away from the tilted surrounding orientation (Gilbert & Wiesel, 1990; Yuan et al, 2017).…”

“…According to the lateral inhibition mechanism, the tilt illusion decreases as the surrounding and central stimulus onset asynchrony increases and vanishes when the temporal gap exceeds about 400 ms (Corbett et al, 2009; Durant & Clifford, 2006; Yuan et al, 2017). If the simultaneous contrast effect of gender is regulated by a similar lateral inhibition mechanism, it would disappear when a relatively long temporal gap was introduced between the surrounding and central stimuli.…”

Following Other People’s Footsteps: A Contextual-Attraction Effect Induced by Biological Motion

“…Take the well-known tilt illusion as an example; a vertical grating can be perceived away from the orientation of the surrounding context (Clifford, 2014). In addition to orientation (Clifford, 2014; Yuan et al, 2017), other basic visual properties, such as luminance (Harris et al, 2011) and size (Chen et al, 2018), have also been revealed to be perceptually susceptible to the contextual information. In general, the repulsive modulation of these visual features is explained by lateral inhibition whereby stimulated neurons are suppressed by the excitation of nearby neurons (Blakemore et al, 1970).…”

Conscious and unconscious processing of ensemble statistics oppositely modulate perceptual decision-making.

“…The target appears repelled away from the inducer in orientation between 0° and 50° but appears rotated toward the inducer when it is between 75° and 80°. Many variations have been extended around the classical tilt illusion (Clifford & Harris, 2005; Motoyoshi & Hayakawa, 2010; Tomassini & Solomon, 2014; Yuan et al, 2017), in which a remarkable finding is that the repulsion effect can survive after the removal of the oriented surround grating from awareness (Clifford & Harris, 2005; Motoyoshi & Hayakawa, 2010) but the attraction effect requires awareness (Tomassini & Solomon, 2014). This is however different from the present study in which the attractive modulation effect appeared when the inducers were rendered invisible.…”