Yes we have all heard about the dress. The internet went wild with it so we asked optician Tom McMahon to explain it for us.

When you look at the model on the left, your eye is naturally drawn to the dress in the centre of the image. But your interpretation of the dress depends on the way your eye perceives the light around it.

Because both blue and yellow-tinged light are present in the image background, some people’s brains perceive the model on the left as being lit by blue light while others perceive the whole scene as being lit by yellow light. But while our brains are making that judgement we’re actually focused on the dress, and so we’re expressing the outcome of an automatic, unconscious judgement about the light as a judgement about the colour of the dress.

This example of the two models forces that process into conscious thought. The dress colours are completely the same on both sides. It’s the backgrounds that vary. And so what looks gold on the left looks much darker on the right, which is why some people see that color as blue and others as brown or black.

Another great example to demonstrate this principle is what I call the ’not-a-dress’ illusion. Are A and B surfaces the same colour????

Just use a finger to cover the place where both parts meet and you’ll find out.

If you still think your eyes are misbehaving make an appointment to see your local optician or pop in to see us at McMahon Opticians in Falkirk

Submitted by Tom McMahon BScHons MCOptom