There's more to this optical illusion than meets the eye.
New research suggests that the well known "spinning woman" illusion doesn't actually reveal if you have a left or right brain.
But first, some (recent) history: The "spinning woman" was a gif created by Flash artist Nobuyuki Kayahara in 2003.
Since the era of the viral image began, it's been seen be millions of people.
The image is usually accompanied by a paragraph that says something to the affect of: 'The direction the woman appears to be rotating determines whether or not the observer has a left or right brain.'
Speaking to Tonic, scientists Arthur Shapiro and Niko Troje explained how the "illusion" is better explained in terms of perception.
Shapiro, a computer scientist at American University, District of Colombia is also the creator of the colour wagon wheel illusion, and Troje is the director of the BioMotion Lab at Queens University, Kingston Ontario.
The pair decided to dissect the image in the upcoming Oxford Compendium of Visual Illusions.
Because of their work, they explained that the 'left vs right' brain idea is "just gibberish".
According to Shapiro and Troje, humans tend choose a viewpoint from above, and therefore most people see the woman rotating clockwise.
He and Troje explain that the spinning woman is a classified as a "reversible image" type of optical illusion, meaning she can be seen doing what appears to be the opposite, almost simultaneously.
For instance, the Necker cube, which observers can also perceive from either above or below.
Troje explained that reversible objects are intentionally ambiguous, and purposefully avoid giving indicators for working out depth.
Humans brains don't care for this, so they impose order and rules where none exist.
This is about survival. Images and movement are processed by the left and right brain hemispheres, but also by the subcortical system, which deals with fear, panic, and rage.
Shapiro explains the advantage of this early warning system, such as recognising a snake stretched out on the ground of a dark path.
He and Troje believe this primeval instinct could be why most humans assume they are seeing optical illusions, like the spinning woman, from above.
Our brains are hard wired to see danger and expect predators to attack from below us, so when we're without information, viewing from above is our default.
As such, the woman appears to rotate clockwise.
In order to see her change direction, Shapiro recommends covering her foot with your hand and focusing on the shadow.
Then by imagining you can see the woman from above or below, it's easy to see her "change direction".
If you can see her change directions without doing that, you may well be a genius.