Image from Time's article on prosopagnosia

Have you ever seen someone and thought, “I know that person…I think”? You probably just aren’t good with names. But there’s an increasing chance you may have prosopagnosia.

A new article in Time magazine delves into the condition. Those who suffer from prosopagnosia—called prosopagnosics—are unable to recognize people based on facial characteristics. Rather, it takes other cues, like hair, voice and other identifiers outside the face. Prosopagnosics are able to see mouths, noses and eyes, but are unable to remember the combination that identifies a person to them.

According to the article, the condition, which was once believed to be extremely rare, is now present in one out of every 50 Americans. That measure up to 5 million people.