Brain: new elements on the mystery of the blue dress

You have certainly not escaped it, the photo of a dress had made the buzz a few weeks ago on social networks. In fact, netizens were tearing each other over the color of the garment, while some saw it blue and black, others claimed it was white and gold.
True mystery 2.0, the CNRS had even seized the case to sketch an explanation as for this curious phenomenon. A team of scientists from the universities of Bradford (England) and Giessen (Germany) who decided to go further and study the different perceptions people have of the same object.

Slight variations in color

Much of the confusion, according to Dr. Karl Gegenfurtner, a lead author of the study, is due to the bluish and yellowish coloration of the photograph and the lack of information about the snapshot for the brain. After studying the image, the researchers were able to explain in an article in review Current Biology that internet users would in fact have perceived the shades of color to be similar, with only a few slight variations that have misled some.
In principle, people should be able to filter the effects of these different variations. However, here, the scientists discovered that the green and red components are completely absent from this photo, which prevents the photograph from sending to the retina the elements necessary for the good comprehension of the image by the brain.

The authors add that depending on the position of the sun, the light could also be more bluish at midday and yellowish in the morning and evening. “The bluish tint perceived by one of the groups of observers is linked to the fact that the dress was exposed to bluish daylight”, assures Dr. Gegenfurtner.

The importance of lighting

Lighting therefore plays an important role. If we look at the background of the photo, it looks very bright. The photo is overexposed, and this changes the nature of the information transmitted to the retina. It is therefore natural to see the dress lighter in the photo than it is in reality, therefore in gold and white. But, in reality, the dress is blue and black (the site that sells it has confirmed this). It is possible that those who see it as is manage to adjust their perceptions to correct the lack of overexposure of the photo, and therefore manage to see it in blue and black.

These phenomena, and the associated brain mechanisms, are complex. Many scientists have been puzzled by such large differences in perception. For example, when placing several individuals in front of a gray screen, some will tend to see a bluish or yellowish color.