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 perception Is That Dress White and Gold or Blue and Black? The New York Times The Great Dress Debate: White and Gold or Blue and Black? The Dress Causes Internet to Go Crazy, Debate Over Whether It's White and Gold or Black and Blue TechEBlog Here's why people saw the dress differently.