“Every now and then, someone will give me context, and I’ll say, ‘Thank you for helping me.’ But I p*** 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, in the US state of New Hampshire, and co-founder of the prosopagnosia research centre Faceblind, run by Dartmouth, Harvard and the University of London.

“For them, it’s a real relief when they learn about prosopagnosia because they realise it’s just a little quirk in their visual system rather than some character flaw.”

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

“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. 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 recognising 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 realise, wow, I’m not like everybody else. Everybody else seems to be able to recognise people’s faces quickly. Whereas for me, it takes me many, many meetings to really feel confident that I can recognise somebody.”

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 recognising 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, in the UK.

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

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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.

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 recognise them, and will ask for reminders of where they met before, Corrow says. Others memorise particular aspects of a person’s face that make 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 not to doubt someone who discloses they have it.

“I haven’t heard of people faking it before. I’m pretty sceptical that it happens all that often.”