With one photograph of a dress breaking the internet more than Kim Kardashian's Paper cover shoot, we count down nine possible reasons why some people see the dress as white and gold, and others see it as blue and black.
Apparently 75% of respondents to a Buzzfeed survey see the dress as White and Gold, but those in the Blue and Black camp are vehement in their conviction.
Here are nine possible reasons why people are seeing two different dresses in the one photo.
1. 'Top-down' processing
This refers to the way in which your brain processes information. It means that we form our perceptions starting with the larger concept, object or visual before our brain works it's way towards the finer details. This could mean your brain is processing the overall image slightly differently to others, which could be as a result of the below factors.
Several publications have reported that the confusion could be due to the way people's eyes change as they get older, resulting in older people seeing one colour and younger people, the other. However, this doesn't explain why people of the same age are seeing different versions or why one person can see two at different times.
3. Sensitive to Yellow
It has been argued that people who see the colour yellow 'more sensitively' will see the dress as gold - which prevents them from seeing it as black.
4. Light scattering
Some reddit users have pointed out that the lace on the dress is 'scattering' the light that hits it in a way that could change perception of the image. In their case, this resulted in a shimmering gold effect. (It's not gold, dammit!)
5. Home light temperature
One theory is that the light colour in our homes can affect what we see. Where homeowners have a standard 'orangish' light, their eyes will readjust, washing out the blue. People who are seeing the image in white light or in the dark will see blue.
6. Night owls
This theory follows on from the previous in that many believe your sleep pattern affects what you see - that night owls are more likely to see the blue and black whereas morning people will see the white and gold. This could be due to the lights mentioned above.
Many people think the device you are viewing the picture on will affect your perception - and that the underexposed photo will appear to be White and Gold on monitors that have their brightness on high.
8. Retinal after-image
The theory of retinal after-image means that if the last thing you saw was bright blue, your brain will over-correct the dress to white.
I'm after checking again and now it's #blueandblack again. This is freaking me out, man.— Clare Cullen/Clisare (@Clisare) February 27, 2015
9. Over/Under Exposure
The photograph, according to the poster, is an overexposed image of a blue and black dress. However, some people's eyes will interpret this image as an underexposed image of a white and gold dress (i.e. with a big shadow). This will then affect how their brains will process that image into colours.
More possible reasons are available on this confused reddit thread and Abobe Photoshop claims it's black and blue.
And of course there's always those people who see the dress as blue and gold. Someone always has to be different!
Here's a new video from YouTube channel ASAPScience which aims to solve the mystery once and for all.