In 2015, a photograph of a dress went viral, dividing viewers over whether its colors were blue and black or white and gold. This optical illusion highlighted differences in human color Optical illusion renews blue and black dress debate nine years on Express.co.uk Color Of 'The Dress' Debate: White & Gold Or Blue & Black Twitter Decides Hollywood Life How I Flipped My Brain's View of the Black and Blue Dress Jeff Greenhouse Here's why people saw the dress differently.