The influence of adaptation on perceived visual location.

We demonstrate a marked effect of prior adaptation upon the perceived position of subsequently presented stimuli using both first-order (luminance-defined) and second-order (texture-defined) stimuli. The effect of varying the contrast of the adapting and test stimuli depends only upon the ratio of adapting/test contrast. Adaptation effects for the two types of stimuli differ in terms of interocular transfer and rate of decay. Whilst adapting and testing with the same type of stimulus (first- or second-order) produces large shifts in perceived position, little or no crossover effect was found. The data are accounted for by a model in which the centroid of the linear combination of after-image and test stimulus is extracted.