Synesthesia is a rare neurological condition that involves the crossing of sensory systems in the brain, such that input from one sense can lead to perception in another sense. For instance, some synesthetes can "hear" in color; different sounds are represented in their minds with different colors. Similarly, other synesthetes might have certain tastes assigned to certain words or sounds.

It's a fascinating condition that scientists say afflicts only around 4 percent of the population. But a new study by researchers from City University in London suggests that synesthesia-— or, one particular form of it at least — might be much more common than previously believed, reports The Guardian.

According to the study, as many as 1 in 5 people — that's 20 percent of the population — might have the remarkable ability to hear flashes of light or quick visual movements. And the ability isn't just a novelty; people who experience it appear to have an enhanced capacity to identify patterns in flickering light signals. This strange crossing of the senses might be so common and natural that those who possess it might not even realize they're special.

“A lot of us go around having senses that we do not even recognize,” explained Elliot Freeman, the study’s lead author.

How to find out if you have this ability

One way to test whether you might be one of these synesthetes could be to peer intensely at a spinning fan while wearing headphones. If your brain still creates a "whoosh" sound despite the lack of input from your ears, you might have the condition. Rapid movements across your visual field or flashes of light of any kind might also produce sounds in your mind if you're one of these synesthetes.

This video illustrates what it might be like to experience the world in this way:

For the study, published in the journal Consciousness and Cognition, 40 participants were presented with pairs of either visual or auditory Morse-code like patterns. They then had to decide whether each pair contained the same or different sequences. Participants were then asked whether they were aware of any sounds accompanying the flashes. Twenty-two percent of subjects reported those sounds. These individuals also performed better on the task, indicating that their ability might be an asset.

“The finding that this ‘hearing-motion’ phenomenon seems to be much more prevalent compared to other synesthesias might occur due to the strength of the natural connection between sound and vision,” said Freeman.