For many people, getting closer and closer to each other, this design triggers an optical illusion: its components seem to rotate.
The image is known as the Pinna-Brelstaff figure, and the reason it seems to move clockwise or counterclockwise has long been a guess.
Now, researchers led by Yong Gu of the Chinese Academy of Sciences have at least answered part of the question.
They determined that the image was causing reactions in the area of the brain responsible for motion detection – but that the neurons involved appeared to be aware of their error after about 15 milliseconds and shut down again.
The researchers explain that their work helps to better understand how the brain distinguishes the perception of reality. he is published in the newspaper JNeurosci.