Optical illusion renews blue and black dress debate nine years on Express.co.uk The actual dress was black and blue. The confusion came from how lighting and color perception tricked people's brains, making some see it as white and gold. It became a viral example Is it white and gold or blue and black? The truth behind the dress debate. CooperVision Decision Making Biases in Group: Is the Dress White and Gold or Blue and Black? Applied Social Psychology (ASP) The Pennsylvania State University