If you saw THAT dress as white, your brain was working overtime

Is white and gold or blue and black? Photos / Supplied

It was the dress that nearly broke the internet, with millions of people claiming they could only see white and gold lace while the rest of the world was convinced it was black and blue.

Now scientists think they have solved the problem of why so many people swore black was white.

After placing volunteers in an MRI scanner and asking them to look at the image, they noticed subtle changes in how the brain was functioning.

People who saw the dress as white and gold had extra activity in the front and parietal areas of the brain which is particularly important in visual perception, mental reasoning and selective attention.

Their brains, in other words, were trying to make sense of the image, leading them to take an extra mental step and believe that the blue colour was a shadow on a white dress.

"These results expand our knowledge of illusion processing in the brain," said Professor Tobias Schmidt-Wilcke of the University Clinic Bergmannsheil in Bochum, Germany.

The bodycon Roman Originals dress illusion baffled the world when it was posted on Twitter in February and retweeted by pop superstar Taylor Swift.

The dress was blue with black lace but because colour is simply a perception made by the brain when light hits the retina, it can look different to other people.