The latest internet fad comes via a GIF of pylons that has people scratching their heads.
The animation, referred to as an “optical illusion for the ears,” was first posted by HappyToast in 2008 but it regained steam Saturday when Lisa DeBruine posted on Twitter, The Telegraph said.
She asked what people experienced when they watched it in an attempt to see if anyone could explain it.
The silent GIF shows what appears to be three pylons jumping rope. But the camera shakes just as the middle one lands, which some viewers believe they can hear or feel.
Dr. DeBruine, from the Institute of Neuroscience & Psychology at the University of Glasgow -- according to The Telegraph -- heard from more than 280,000 people by Tuesday, with a large majority saying they thought they heard a thudding sound.
“My gut says the camera shake is responsible for the entire effect,” said Twitter user Jeff Weiss. “Anything that shook the camera like that, would probably make the “thud” sound.”
Another user, Andrew Kemendo said, “The brain is “expecting/predicting” what is coming visually and then fires a version of what it expects across the relevant senses. Also explains why some might “feel” a physical shake.”
In an interview with the BBC, DeBruine seems to be as stumped as everyone else.
“I don’t know why some people hear it very clearly, others only feel it, and others perceive nothing at all,” she said. “I thought some of the vision scientists I follow would be able to explain it right away, but it seems like there are several plausible explanations and no clear consensus.”