School of Psychology - Activities - Demonstrations - Spatio-Temporal Rivalry

Login to the School of Psychology

Demonstration - Spatio-Temporal Rivalry

Exposure to a physically coherent moving object elicits two conflicting illusory percepts

Recently we discovered a phenomenon, we call Spatio-Temporal Rivalry (STR), wherein exposure to a physically coherent moving object elicits two conflicting illusory percepts.

The stimulus used in reported experiments consisted of a rotating windmill. The arms of the windmill either had a single green stripe at the mid-point of otherwise red arms, or consisted of multiple red and green stripes.

With the first type of stimulus, STR is characterised by mutually exclusive intermittent appearences of an illusory static green ring at the mid-point of the windmill arms, and by intermittent dissapearences of all trace of green, leaving an impression of an illusory red rotating windmill.

CAVEAT: The online demonstration is suboptimal. Optimal effects depend on high rates of local repetition (~10Hz) and on equating red and green luminance. We cannot ensure either status over the web, but the effect should be sufficiently robust for you to get some idea of the perceptual effects observed. Also, due to the poor sampling rate available over the web, we have used a sinusoidal luminance modulated windmill, as opposed to the square wave pattern used in reported experiments.

Accessed: 4317 times
Created: Monday, 7th December 2009 by paulj
Modified: Wednesday, 17th April 2013 by paulj
Psychology News, Events & Publications RSS 2.0 Feed School of Psychology on Facebook School of Psychology on Twitter School of Psychology on Google Plus School of Psychology on Linkedin School of Psychology on YouTube
Share this page on Facebook Share this page on Twitter Share this page on Google Plus Share this page on Linkedin