According to a new study from City University of London, as many as one in five people "hear" the sound of flashing lights and rapid movement, even if those visual cues are completely silent. They call it "visually-evoked auditory response," or "vEAR" for short. By contrast, less than one in 20 people experience other types of synesthesia, so this more common variety might hold some answers as to why it happens in the first place.

You might even experience it yourself. Although it didn't involve flashing lights, a viral GIF from 2017 made people all over the world suddenly aware of their vEAR when they "heard" the thudding of this jump-roping power pylon.

But what is it, and why does it happen? We don't know for sure, but one thing we can say is that it might explain some other, more vanilla ways of perceiving the world. Ever notice how much fun it is to see a rock concert with a light show? Or how a rave just isn't a rave without the barrage of lasers? And don't even get us started on Cher's "Believe" music video. Humans sure do like lights with their sound, so maybe it's not so surprising that our brains are wired to imagine noises when the lights are too silent for our liking.

In this study, the researchers recruited 4,128 participants to fill out an online survey about 24 silent video clips. Roughly 21 percent of those responding reported that yes, they did hear something when they watched those clips, and what's more, they heard sounds even when the clip was completely abstract. That means it's not just a matter of the brain "filling in" the sounds that happen (like the "sproing" and "thud" of that jumping electric pylon), but an intuitive link between the lights we see and the sounds we (think we) hear.

So was there something special about the people who could hear the flashes that set them apart from those who couldn't? Well, yes. Of the 21 percent whose "visual ears" perked up to the GIFs, many of them reported experiencing other auditory phenomena such as tinnitus and musical imagery (getting a song stuck in your head, aka an "earworm").

"Some people hear what they see. Car indicator lights, flashing neon shop signs, and people's movements as they walk may all trigger an auditory sensation," study author Dr Elliot Freeman said in a press release. "We think that these sensations may sometimes reflect leakage of information from visual parts of the brain into areas that are more usually devoted to hearing."

This phenomenon reinforces the idea that the senses are something more than just the tools we use to learn about the world around us. They're a part of us, and they don't just tell us what we experience — they shape those experiences.

See how the human senses shaped history with Diane Ackerman's national bestseller "A Natural History of the Senses." We handpick reading recommendations we think you may like. If you choose to make a purchase through that link, Curiosity will get a share of the sale.