Brad Pitt says he has prosopagnosia. What is that, and what do experts say about it?

Imagine meeting someone at a party and really hitting it off. The next time you see them, they are completely unrecognizable.

Experts have labeled this condition prosopagnosia, otherwise known as face blindness. And it may affect more people than you think, including one Hollywood A-list actor: Brad Pitt.

Pitt, although not formally diagnosed, told GQ magazine in a cover story published June 22 that he may have prosopagnosia, prohibiting him from recognizing new faces or remembering people he meets in social settings – though Pitt says “nobody believes” he has the condition.

In a 2013 cover story for Esquire, Pitt spoke out about how people have reacted to his lack of facial remembrance.

"So many people hate me because they think I'm disrespecting them," he told the magazine. "So I swear to God, I took one year where I just said, This year, I'm just going to cop to it and say to people, 'OK, where did we meet?' But it just got worse. People were more offended. Every now and then, someone will give me context, and I'll say, 'Thank you for helping me.' But I piss more people off. You get this thing, like, 'You're being egotistical. You're being conceited.' But it's a mystery to me, man. I can't grasp a face and yet I come from such a design/aesthetic point of view.”

Pitt isn’t alone in his fears that people find him aloof or unfriendly. Experts say this is common among people who have prosopagnosia and offer advice on what to do if you think you have it.

“Often, people who have face recognition problems attribute their difficulties to maybe just not caring enough about other people and not trying hard enough and they often feel guilty about this,” says Brad Duchaine, a professor of psychological and brain sciences at Dartmouth University. “For them, it's a real relief when they learn about prosopagnosia because they realize it's just a little quirk in their visual system rather than some character flaw.”

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What is prosopagnosia?

Prosopagnosia is a disorder where someone’s ability to recognize faces or identify someone by their face alone is impaired, according to Sherryse Corrow, a professor of psychology at Bethel University.

“Somebody who has prosopagnosia, they can see just fine," Corrow says. "There's nothing about their low level vision that's affected; their memory is usually just fine."

In the brain, there are about 12 face-selective areas split between the right hemisphere and the left hemisphere that determine our face processing, according to Duchaine, who leads a Prosopagnosia Research Center. When these areas are not working properly, we have difficulty with facial recognition.

Two types of prosopagnosia exist: developmental and acquired. Those with acquired prosopagnosia develop the disorder after brain damage, Duchaine says. People with developmental prosopagnosia have never experienced significant brain damage yet have had trouble recognizing faces all their lives.

“A lot of people with prosopagnosia won't notice it until their face recognition is really pushed,” Duchaine said. “So they go to college, and they're meeting all sorts of new people. And then they realize, wow, I'm not like everybody else. Everybody else seems to be able to recognize people's faces quickly. Whereas for me, it takes me many, many meetings to really feel confident that I can recognize somebody.”

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Signs you may have prosopagnosia

Other warning signs could assist in identifying prosopagnosia.

If you’ve had trouble following television or movie plots because the actors look the same to you, you may have prosopagnosia, according to Duchaine.

Another telltale sign is difficulty recognizing family members in a “context where you are not supposed to see them,” says Constantin Rezlescu, a lecturer in experimental psychology at University College London.

For those who believe they may have prosopagnosia, Corrow recommends reaching out to a prosopagnosia research lab, as a general physician might not have the expertise to diagnose the condition.

Rezlescu suggests those with suspected prosopagnosia take the Cambridge Face Perception Test, where they examine the differences between faces, and the Cambridge Face Memory Test, which tests a person's ability to remember a face.

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Navigating the world with prosopagnosia

People with prosopagnosia have learned various workarounds to identify a person, since a cure remains elusive.

Some people are upfront about the condition and tell others that they might not recognize them, and will ask for reminders of where they met before, Corrow says. Others memorize particular aspects of a person's face that makes them distinguishable, such as beauty marks, facial hair or even a person's teeth.

Alternative strategies include focusing on a person's voice, clothing or hairstyle.

Duchaine says to avoid doubting someone who discloses they have it:

"I haven't heard of people faking it before. I'm pretty skeptical that happens all that often."

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This article originally appeared on USA TODAY: Brad Pitt may have prosopagnosia. Experts talk definition, what to do