Rainbow Colour Illusion

This rainbow after-memory illusion demonstrates the dynamics of retention of a colour image in the short-term memory by a technique of multidimensional scaling under conditions of delayed administration of a second stimulus in a pair. Okay, bit heavy? Just see it in action. Stare at the dot in the centre of the image for twenty seconds or more then move your mouse over the picture or tap on it with your finger if using a tablet or smartphone. The black and white image of the waterfall then appears to have a colour rainbow over it even thought it's actually a black and white photograph! This is easily one of our favourite online optical illusions! After you experiment with this rainbow illusion why not check out our other free online visual and optical illusions, we've collected the very best.