Perceptual asynchrony refers to the demonstration, first made by and Semir Zeki in 1997, that two simultaneously presented attributes of the visual world – for example the color and direction of motion of a single visual stimulus – are not perceived simultaneously but asynchronously, with the color of the visual stimulus perceived before its direction of motion by about 80 – 100 milliseconds. The experiments through which this was derived were pairing experiments in which subjects are asked to determine the color and direction of a single stimulus that is moving up and down (or right and left) and changing its color from, say red to green, while doing so – the change in the color and direction of motion being in and out of phase with respect to each other. There are several variants of th