Last winter I got an email inviting me to a dinner party. Let’s say the host’s name was Barry Johnson. I’ve known him and his wife casually over the years, but this was the first time I’d been asked to their house, and I was excited to go.

The evening arrived, and I rang the bell of their apartment. A pleasant-looking man answered the door, clasped my shoulders and kissed me on both cheeks. It was a disconcerting moment – I had no idea who he was – but the truth is that these things happen fairly regularly. I don’t have a great visual memory, and I often have trouble recognizing people I’ve met before. Sometimes the people I’m talking to aren’t the same people I think they are. I rummaged around in my mind, trying to remember where I’d met this apparent friend of Barry’s who, and this did seem strange, felt so at home in Barry’s apartment that he was taking my coat and hanging it up in the cupboard.

He led the way into the living room, already full of guests. I didn’t recognize any of them, either. ‘You remember my wife?’ he asked, gesturing to a tall unfamiliar lady holding a glass of wine. I gave her a huge hug, which seemed to startle her, and did not help me much either. I seemed to be in the wrong place. There are a number of techniques you can employ in these situations, but they appeared not to be working. A side table containing a piece of mail or a magazine with an address label on it would really have come in handy just then.

Sometimes it helps to remember the things that used to happen to characters in The Twilight Zone. In one of my favourite episodes, a couple wakes up, freaked out and disorientated, in a strange bed in a strange house in a strange neighbourhood. The food in the refrigerator is actually some inedible substance painted to look like food; the train they board in an effort to escape deposits them back to where they began. (It turns out they’ve been kidnapped by giant aliens and installed in a kind of large-scale terrarium with a toy railway running around the perimeter.) That’s how I felt that night, trapped in a science-fiction story written by someone else. An icy chill moved up my body, sweat poured down the back of my dress and my brain crackled with extra noise, like stereo feedback. I’ve had my share of mishaps over the years – getting into strangers’ cars outside the supermarket when I thought I was getting into my own car, driven by my own then-husband; showing up at the wrong cocktail party but not realizing it for some time, since often I don’t recognize the guests even at the parties where I’m meant to be; repeatedly asking a colleague named Charlie if he knew where Charlie was, because I had confused him with someone named Walt; mistaking the neighbours’ house for my own and trying to use my key to open their front door as they watched through the window; and inviting a strange man on the street to a book launch because I thought he was someone I’d known for ten years, a misunderstanding compounded by the fact that both men, the stranger and my friend, are called ‘Rick’, so this person, perhaps thinking that he knew me, or should know me, or maybe having nothing better to do, ended up coming to a party where he knew nobody at all. Plus, I told all our mutual friends that Rick – the real Rick, who is a writer – had split up with his wife, which was not the case, though the fake Rick, who turned out to be a reality-television producer, had.

But this seemed like the worst situation yet.

Standing in these people’s living room, I assessed the possibilities. 1. They were my friends but I didn’t recognize them. 2. They were not the friends I thought they were, but other friends who I also did not recognize. 3. Nobody was anybody’s friend: I had gone to the incorrect dinner party and they had mistaken me for somebody else. Perhaps all of these things were true. I went into the bathroom, took out my phone and starting texting my friends. ‘I do not know what to do,’ I said.

It was a December morning, a little bit later. I was perched on a sofa in an anteroom in the Capitol building in Denver, waiting to talk to the governor of Colorado about a condition called prosopagnosia, or face blindness. I survived the dinner party, thank you for asking, but a few interesting things had happened since that evening. First, I’d met a woman married to an old friend of mine who announced that she had face blindness and that if we’d met before (we hadn’t, I didn’t think) she was sorry, but she did not know who I was. Her remark stirred a fuzzy memory of an article in the New Yorker I’d read a few years earlier by the late neurologist and author Oliver Sacks, who chronicled his own struggles with prosopagnosia. His was a severe case, but some of his experiences had seemed resonant and familiar, and I’d left the notion to float around in the back of my mind.

I don’t have a great visual memory, and I often have trouble recognizing people I’ve met before. Sometimes the people I’m talking to aren’t the same people I think they are.

After I met the woman, I went home and re-read the article. It was now after midnight, but I took an online face-blindness test that she had recommended. My score, frankly, was very bad – in the lowest possible percentage for one of the groups of questions – so that it appeared (at least according to the internet) that I myself had some form of prosopagnosia.

I started mentioning it to friends, as a possible explanation for what I’d always assumed was simply sloppy behaviour or some sort of egocentric attention-deficit problem on my part. My friend Michael told me that among the prominent people said to suffer from it – the artist Chuck Close, the anthropologist Jane Goodall – is the Colorado governor, John Hickenlooper. I emailed Hickenlooper and he said that yes, he is in fact a face-blind governor.

How would that work? I wondered. It’s one thing to be a regular person; it’s another to be a public figure in the kind of job where accurate recognition of other people would seem to be a virtue, if not a necessity. How can you inveigle money out of donors, suck up to voters, make deals with legislators or operate an effective office if you can’t remember who anyone is? Oddly enough, Hickenlooper’s handicap appeared not to have affected his career. A Democrat in a state that does not always love members of his party, he had served eight years as mayor of Denver before being elected governor in 2011, and re-elected in 2014. He has a reputation for being engaged, chatty, convivial and warm. Everyone calls him Hick. Before he was a politician he ran a successful chain of microbreweries in the city. Before that he was a geologist.

He has an almost uncannily severe inability to recognize faces. Though we had met several weeks earlier, for drinks in New York, he could not remember what I looked like on this new occasion in Denver. (To be fair, I could not remember what he looked like either.) I was looking forward to observing him in action. As a reporter who speaks mostly in questions, I probably have a better-than-average chance of bluffing my way through dicey situations. But politics, it seemed to me, is another thing entirely. While we were on the subject of prosopagnosia, how did Hickenlooper handle his years in the restaurant business, which would have entailed long hours of face-to-face encounters with customers?

‘If you were going to torture a person with face-blindness, you would put them in charge of running a high-volume restaurant,’ Hickenlooper said, ‘and then you would make them governor of a state.’

As it happened, the governor was throwing a party later that night at his official mansion for hundreds of important Coloradans involved in community service. The idea filled me with anxiety, as I imagined all the people he would potentially not recognize. How would he get through the evening? Somewhat perversely, Hickenlooper told me, as he prepared to leave his office, his extreme extroversion – he had to take a Myers-Briggs personality test for his geology job and scored off the charts for sociability – means that he actually likes parties. ‘It’s kind of an adventure,’ he said.

Some politicians have a gift for recalling faces. Bill Clinton, Hickenlooper said, met him once and then remembered exactly who he was several years later. Others have ‘body men’ to help out. ‘Wife or daughter?’ Selena Meyer, the sometime president played by Julia Louis-Dreyfus in Veep, hisses at her body man in one episode, as an older politician approaches with a younger woman. For several years, Hickenlooper too had had an advance man who was pretty good with names, but that person had moved on and his replacement, Conor Hall, told me that he had been on the job for only a few weeks and didn’t know anyone yet.

The party started. The mansion was decorated for the holidays, the bar was open and the crudités and the dips were on display. The guests came in trickles, then in hordes. Hickenlooper planted himself in a central spot. Women, men, families, couples – they kept coming. I watched him operate. He always looked interested. He always looked them in the eye. He used a few stock phrases, depending on the situation. ‘Hey, how are you?’ he’d say when the person seemed vaguely familiar. ‘How has your year been?’ he would say to people who did not seem familiar, but who he thought ought to be. For people who drew a complete blank, he would say, ‘Merry Christmas!’, or, even more generally, ‘Happy Holidays.’ He had a warm conversation with a pair of women. ‘I couldn’t tell you who either of them is,’ he whispered to me, after they had left.

Along came Armin Afsahi, vice-chancellor of the University of Denver. He had recently run into the governor at a fundraiser, soon after being seated across from him at a dinner. ‘It was about the fourth or fifth time we’d met,’ Afsahi told me. At the fundraiser, Hickenlooper and Afsahi got to talking about education. ‘Finally he said, “Sorry, I have this thing called facial blindness,”’ Afsahi recalled. ‘He fooled me the entire time. He’s so good at – I won’t say pretending – but what’s the right word?’ He added, ‘He could win a game show.’

The people kept coming. Hickenlooper never faltered. ‘Yes, of course I remember you,’ he said, as he grasped a woman’s hand. He posed for a picture with another couple’s kids. ‘You should be very proud of your father,’ he said. (‘I have no idea who those people are,’ he murmured as they walked off.) He had better luck with Robert Schuham, head of a marketing agency, who is 6’4” and strikingly handsome. ‘He’s a serial entrepreneur,’ Hickenlooper said, ‘and his height sets him apart.’

By now, Hickenlooper had started introducing me to guests and telling them that I was writing about face blindness, which was a useful way for him to ascertain any names he did not know. Afterwards, the guests said that they were not particularly bothered by Hickenlooper’s gubernatorial vagueness.

‘Here’s the thing – he always looks like he’s happy to see you,’ said Patty Calhoun, editor of a weekly alternative newspaper in the city. ‘He’s also one of the most extroverted people on the planet. He would go to the opening of an envelope.’

Lieutenant Governor Joseph A. Garcia, was also there. He was the only one wearing a name tag, which was an exciting thing to me – I think everyone should wear a name tag at all times. (‘I love name tags,’ Hickenlooper said later, ‘but you’ve got to be really good. No one wants to see your eyes go down to their name tag and back up.’) Garcia pointed out that if you have to have facial blindness, hosting a party is easier than being a guest. ‘If you’re the centre of attention, then you have guaranteed social interaction,’ he said. ‘You will never be left alone with no one to talk to.’

Was he sure that Hickenlooper knew who he was? ‘As far as I know he recognizes me, and if he doesn’t, he does a pretty good job of disguising it,’ the Lieutenant Governor said. He watched his boss chat with the guests. ‘He’s an operator, in the best sense of the word.’

By now I was exhausted from meeting all those people. I could recognize the governor, but not the other people I’d spoken to, including the chief of staff, whom I’d had a long conversation with and was afraid I’d unknowingly run into again. Just as I was preparing to leave, another man came up.

‘Governor Hickenlooper! Thank you for your service,’ he said. He mentioned that they had met and had a long and interesting discussion two days earlier.

‘Remind me who you are?’ Hickenlooper said.

As a child, Hickenlooper took for granted his hazy confused feeling of not knowing – his inability, for instance, to distinguish between his various aunts and his various uncles. As an adult, it affects him in a constellation of ways. At the movies, he can’t differentiate between the characters – who is the DA and who is the defence attorney? Which shady businessman is which? – and so can’t follow the plot. ‘Two male leads are roughly the same age and have roughly the same hair, and I’m toast,’ he said.

When he ran the restaurants, Hickenlooper prided himself on welcoming his customers, but often had to pretend he knew who they were. Now, he often fails to recognize people who work for him, especially if he sees them out of context. Sometimes he mistakes them for random visitors. (He tends to get it after the sixth or seventh encounter.) He has his strategies. In meetings he’ll take out a pad and quickly sketch out the seating plan, so he knows who is where. When his staff hands him his daily schedule, it always includes thumbnail photographs of the people he’s due to see. At receptions he uses diversionary tactics so as not to alert people that he’s checking out their name tags. ‘Oh, yeah, do you know Andy Reid over there?’ he’ll ask, for instance, pointing vaguely across the room.

The governor often fails to remember people he’s met repeatedly in an official capacity, even if they are famous, such as the musician Ryan Tedder or, exceptionally striking, like Genevieve, Tedder’s wife. ‘It doesn’t matter how big a celebrity – it’s just not in the toolbox,’ Hickenlooper said. After his divorce, he sometimes failed to recognize women he was dating, including Robin Pringle, who is now his wife. The first half-dozen times they met, Pringle told me, ‘he had no idea who I was.’ Early on in their relationship, he had a long conversation with her but believed he was actually speaking to a different person who is also tall and has dark hair and who is a friend of hers.

One afternoon some years ago, when he was still a businessman, Hickenlooper was hanging out at the bar of one of his restaurants. A man came in and sat next to him. ‘He didn’t say anything – he just sat at the bar and was mute,’ Hickenlooper said. About half an hour later, the man ordered a beer, and Hickenlooper realized it was Sydney Kennedy, his half-brother. ‘He had grown a little bit of a beard,’ Hickenlooper said. (A new kind of hairstyle can often prove challenging to a prosopagnosic.)

The town was crawling with legislators of similar appearance. There were so many of them! So many paunchy, middle-aged men in ill-fitting suits. ‘Remind me how to spell your name’ only works up to a point.

His life changed in 2010 when he picked up the New Yorker and saw the Oliver Sacks article about face blindness, the one that had seemed so striking to me. He felt a sudden flash of relief, as if someone had cleaned the cobwebs out of his understanding of himself. ‘I’ve had difficulty recognizing faces for as long as I can remember,’ Sacks wrote, recalling his struggles to fit in at a school where he didn’t recognize his own classmates. ‘It did not occur to them (why should it?) that I had a perceptual problem.’

Hickenlooper has now developed a policy of mentioning it up front. ‘I just confess,’ he said. ‘I say, “It’s a weird thing, but do not be offended, especially if I’m preoccupied or whatever.” I always want to make it sound like I’m a little more normal and don’t have a disability.’ He always adds: ‘Some people have trouble with names; I have trouble with faces.’

For years I too thought something was a bit off. The visual world often seemed tenuous, impressionistic, harder to negotiate than the emotional or intellectual worlds. I couldn’t recognize things I should have recognized. Other things seemed familiar but in fact were not. As a child I hated situations where there were a lot of grown-ups at once – a gaggle of parents, a crowd of teachers. I’m better at coping now, but my techniques can misfire. Once I went to a party and asked a friendly-looking guest to point out the hostess, only to find that she was in fact the hostess herself, the person I was meant to know. In the hospital, woozy on morphine and a little crazy after my c-section, I pointed an accusatory finger at a man holding a baby in the nursery, which, in my defence, contained eight identical-looking babies swaddled in eight identical blankets. ‘That’s my baby!’ I said wildly. (Wrong baby; mine was still in her cot.)

Work presents its own set of problems. It helps if you interview someone, and then see them again, to remember what they look like. The New York state government in Albany, which I had to cover a while back, was particularly challenging. The town was crawling with legislators of similar appearance. There were so many of them! So many paunchy, middle-aged men in ill-fitting suits. ‘Remind me how to spell your name’ only works up to a point.

It’s not just people; it’s places and things too. Objects morph into other objects and then fade away in my mind, and it’s hard for me to differentiate one thing from another or locate it when there are a lot of other things around it. I can’t remember the layouts of people’s houses. I’m not the sort of reporter who is good at describing people or things, except the way you would in a children’s book: the man is tall, the house is white, the car is big, the bicycle has two wheels. Most of my articles lack any meaningful physical description.

My prosopagnosia is not consistent, exactly, which makes it more puzzling. I can recognize my close friends and family, or people I’ve met enough times. I can recognize people if they’re in the correct context, if they’re wearing the same clothes as before, if they’ve kindly remained in the same spot or if their looks are particularly arresting. I rely on things like voice, hair, bearing and body shape, the way someone walks, the way they sound. Little things throw the system off. One of my closest friends at the paper is bald, which is great, until he puts on a hat.

At work I tend to confuse people with each other. For months I’ve been saying hello to a woman I see a lot in the hallway. I don’t know who she is, but I used to think she was someone else. By the time I saw her and the woman I mistook her for together and realized that there were two of them, it was too late. I’d made a fake hallway friend. It’s probably most embarrassing in specific social situations. Once in a restaurant the maître d’ seated me at a table with a man – it was our second date – and I started talking to him. He looked startled. So did the man I was meant to be meeting, who was sitting several tables away.

There’s a family in Anne Tyler’s The Accidental Tourist whose members suffer from, among other things, extreme spatial disorientation. Released into the world, they cannot find their way around it. That’s how it seems to be with me. I’ve lived in the same place for the last four years and still walk past it without realizing it’s my house. Sometimes I walk down a nearby street, thinking it is my street. Usually when I get out of the lift on my floor at the office I turn in the wrong direction. Meanwhile, I can see a painting and tell you what is in it – some nymphs sitting around, a man waving a sword – but I’d never be able to pick it out in a line-up. At the museum, I’m the person reading the explanatory card instead of looking at the picture.

Sometimes I have worried that my problem is a failure of character rather than biology – a psychological issue. Maybe it’s disregard, thoughtlessness, an inability to pay attention, to be generous, to make an effort. It feels as if you should be able to do better just by trying harder. Once I was meeting some friends at a restaurant and introduced myself to a woman at the table. She glared at me. ‘We’ve met about five times already,’ she said. I told her that I had trouble with faces, I’d read this piece by Oliver Sacks, etc. etc. No, she retorted, she didn’t believe that; the problem was that I was lazy and self-centred. I tried to defend myself, but I thought that maybe my position was indefensible, and I went home.

Or perhaps it’s a reaction to something in my childhood. I grew up with a mother who was obsessed with appearance, who thinks that good-looking people are superior to ordinary people and that clothes reflect a person’s character. In addition to cosmetic issues – my hair and its many deficiencies is one of her favourite topics – she has a particular fixation on house decor and a tendency to lecture about what is correct and what isn’t, what looks good and what doesn’t, where things ought to go. As a result my mind bleaches white and an exhaustion sets in when I consider these topics. I can’t get a fix on them. I once interviewed someone who said that they only way he knew where to hang the pictures in his new house was by looking at the squares of dirt left on the walls by the previous tenants. That sounds about right to me. What is in our heads, what we say, how we feel, what we read, what we think – those things seem more tangible to me than what is in front of us.

He loves gardening but has trouble differentiating between plants ‘if I see them unexpectedly’, he said.

I thought about all this a lot when I started learning more about people with prosopagnosia. I read a novel called Face Blind, whose main character is always described in extreme terms – he sees faces ‘that his brain saw the way it saw a white sheet,’ the author writes, which strikes me as a little over the top and probably not accurate, since it doesn’t really work like that. But I wondered what was really going on, and if there was something I could do about it. I decided to go to the prosopagnosia lab and get tested.

One of the foremost researchers in prosopagnosia is named Brad Duchaine, and he is a professor of psychological and brain sciences at Dartmouth. He’s been studying face blindness for about twenty years, since he was twenty-six, and journalists often make pilgrimages to his lab. People are interested in face blindness. It’s such an odd notion.

Hanover, NH, was covered in a light dusting of snow when I arrived. Duchaine had explained where his office was in relation to my hotel, but campuses are particularly difficult to negotiate. All those tangled paths and big, similar buildings at unlikely angles. It’s easy to take a wrong turn and end up on an unexpected adventure on the other side of the quad. Duchaine came out to meet me, led me to his office and handed me over to a graduate student. The tests took place in a small office with a computer set up at a desk.

Testing for face blindness is prescriptive, not proscriptive. In other words, researchers cannot look inside your brain and tell you whether you suffer from it; although there are regions of the brain known as face-selective areas, which show a stronger response to faces than to objects when a subject is undergoing a brain scan. The diagnosis depends on two things: self-reporting – monitoring your experience with face recognition in daily life – and how you perform on visual-recognition tests.

A classic standard measure of prosopagnosia is known as the Cambridge Face Memory Test, developed over several years by Duchaine and described in a paper by him and his colleague Ken Nakayama in 2006.

It starts simply. You see three images of a man with no hair: right profile, left profile, full face. It’s a composite person, not a sketch, so it looks vaguely real, something you might see at a police station. The man has the air of someone who spent some time in prison. He remains on the screen for a bit and then goes away, whereupon three more images pop up. For each image you’re meant to pick the one matching the first guy. (They all look kind of alike, with features that are variations on a theme.) Then another man flashes on the screen, an adjusted version of the first one, and you repeat the exercise with further sets of images.

It gets harder as it goes along. They all looked equally familiar and equally mysterious. It was difficult to pinpoint what distinguished one person from the other. Some had striking features: big lips, bright eyes, prominent chins. One guy looked like Matt Damon; another had thin, cruel lips, like Ralph Fiennes playing Voldemort; a third guy had a chin like an anvil. But then even these distinctions began to blur and the people were washing together, and there was no option but to guess.

In the second part of the test you see a bunch of faces all at once and then have to pick out, from groups of faces that come up later, which ones you’ve seen before. ‘The correct answer can be any of the six faces,’ the screen warned. ‘The incorrect faces are sometimes very similar to the target face.’

No kidding.

In the third part, the people’s faces came up again – but in this case they were obscured by tiny dots, as in a Seurat painting. A few looked vaguely familiar – I thought I spied my friend with the anvil chin a few times – but otherwise it was pure guesswork. A group of generic faces in a crowd.

I met with Duchaine afterwards to go through the results. I had correctly answered 32 out of 72 questions. The average person, he said, gets 58 questions right. (A completely random score, just guessing on every question, would be expected to yield 24 correct responses.) The test allows for a standard deviation of 7, with scores that are more than two standard deviations below the average – that is 43 – considered problematic.

‘So that 32,’ Duchaine said, ‘that’s a bad score.’

I took some other tests – the ‘Famous Faces Test’, which I was pretty good at, on account of knowing what famous politicians and celebrities look like; a series of exercises using photographs of faces, horses and houses, which did not go so well. You’d see a series of fifty photos in each category, and with each new image you were meant to say whether you’d seen that particular one before or not. I made 12 mistakes with the faces, 8 with the horses, and 18 with the houses, which is a particularly bad number (the average person makes 4 face mistakes, 6 or 7 horse mistakes and 3 house mistakes).

‘What these numbers suggest is that it’s not just faces you have a problem with, but general visual recognition deficits,’ Duchaine said.

There are two types of face blindness: developmental, in which something goes wrong during a person’s development, most likely before they are even born; and acquired, in which a person has normal face recognition but suffers some sort of brain damage that throws it off kilter later on. A key case in the literature was that of a 24-year-old Second World War veteran who had lost the ability to recognize even himself after being shot in the head. He became the impetus for the naming of the condition; writing about his plight, the German neurologist Joachim Bodamer joined the Greek words for ‘face’ and ‘non-knowledge’ to arrive at prosopagnosia.

But most cases are congenital, most likely caused by something misfiring in a developing brain, according to Duchaine. ‘Face processing works in several stages,’ he said. First, there’s perception – the ability to take in and differentiate among features in a face. Next, there’s the question of visual memory, whether you can remember what you’ve seen. ‘If I’m going to encounter you three days from now, I’m going to have to match the incoming perception with a representation that I have in my memory and say, “Oh, here’s Sarah,”’ Duchaine said. ‘You can imagine if one process isn’t working normally then the other isn’t going to be much use. Some people, neither is working well, though it’s hard to pull them apart.’

Duchaine’s faceblind.org website went online in January 2002. Some 12,000 people have been in touch through the site in the past fifteen years, he said, usually after some jarring incident that makes them wonder what is wrong with them and sends them straight to the internet, the way you would if you developed a weird symptom, like an unexplained burning sensation in your feet. ‘They say, “I’ve got to figure this out,” and they Google “face recognition problems”,’ Duchaine said.

Some prosopagnosics get lost in their own homes. ‘We hear about people failing to recognize themselves,’ Duchaine said, ‘though I don’t want to say it’s real common.’ Sometimes these people catch sight of themselves in the mirror and think they are looking at strangers.

Through Duchaine, I got in touch with David Fine, a retired gastroenterologist in his sixties who lives in London and is among the more extreme cases the lab has encountered. Once he failed to recognize his own long-time secretary when she got up for a few minutes and then came back into the room with her hair up instead of down. The two were sitting at opposite ends of the same desk. ‘I did a double-take and eventually said, “Is that you, Jan?”, because as far as I was concerned, she was a different person,’ Fine told me over the telephone. Once, meeting some colleagues in a pub, he was describing his condition to a new acquaintance. ‘I was explaining to the woman that I wouldn’t recognize her the next time I saw her, because I had this problem called prosopagnosia,’ Fine said. ‘And I said if my own son were here, I wouldn’t even recognize him.’ That was indeed true; his son had suddenly arrived at the pub. Suddenly, Fine recalled, ‘The young man standing next to me said, “Hello, Dad.”’

He loves gardening but has trouble differentiating between plants ‘if I see them unexpectedly’, he said. He often can’t pick himself out in photographs. His wife has to sit next to him during movies or TV shows and explain what is going on. The people he does remember tend to have prominent features. ‘A man last night said, “How do you recognize me?” and I said, “If you really want to know, it’s the gap between your teeth,”’ Fine said.

He, too, had a moment of epiphany. It came in 1997, when he was inducted into the Royal College of Physicians.

‘We were having a glass of champagne when a man bounced up and said hello to me, and I hadn’t got a clue who he was,’ Fine said. ‘It turned out he was a professor of psychiatry who was a friend of mine and deputy dean of the medical school. I said to him, “Who are you?” and he said, “I’m Chris.” And I said, “Chris who?” The man said, “I can’t believe it – you must have prosopagnosia.”’

Fine wrote the word down, did some investigating, and finally got in touch with Duchaine. ‘He said, “Oh yes, you’ve definitely got it – you’re in the bottom 29 per cent,”’ Fine related. ‘I said, “That’s not bad, it’s within the normal range.” He said, “Not within the bottom of the population, but within the prosopagnosic population.”’

The condition is thought to affect, very roughly, between 1 and 2.5 per cent of the population, Duchaine said. There are a lot of grey areas, which makes it an inexact science, and of course many people can’t remember names or are simply socially awkward, which are different problems but can seem like the same thing.

‘Regardless of where you want to draw the line,’ Duchaine said, ‘there are a lot of people with face recognition problems that affect them from time
to time.’

It was still last winter. I was still at the strange dinner party with the unexplained host and I was still sweating in the guest bathroom, while a person unknown to me milled around outside. I thought about slipping out the back door, but it wasn’t clear if there was one, and there was also the problem of my coat, stranded in the cupboard.

I finally came out and made unhelpful small talk with some of the unknown guests. We sat down to dinner. I was seated to the left of the host whose name, it turned out, was in fact Barry, although it was clear he was not the Barry I knew. (That Barry is from Zimbabwe; this one seemed possibly to be from California.) I hadn’t yet caught his last name. He had just published a book about a complicated but boring topic. His friends seemed to be academ­ics. The guy to my right specialized in second-century Talmudic law.

I tried to use my professional training to interview Barry without him realizing it.

How were things, I asked, what had he been doing? I asked him where he had been recently, where he was planning to go next, what he was working on, whether he liked living in the place he was living in, what plays/movies he had seen, what books he had read, what were his views on New York at this time of year. Finally he referred to a specific literary event in London a few years earlier. I remembered going there, but not what happened once I arrived. Apparently we were seated together, and had a long and fascinating conversation. When I finally went home and did some research, it became clear that there had been two misunderstandings working in concert. The most obvious was the failure to remember, or recognize, the guy. But there had been a previous error: the dinner invitation, it turned out, had not come from Barry Johnson, my Zimbabwe friend, but from Barry Jackson, a different person. My brain hadn’t registered the name on the email correctly, just as it hadn’t recognized his face correctly. That wasn’t prosopagnosia, but general sloppiness.

I was very sorry about the whole thing and wrote a fulsome thank-you note to Barry and his wife thanking them for a lovely evening. (Obviously I did not apologize for going to the wrong house, failing to recognize them, hiding in the bathroom and thinking all their friends were boring.) We exchanged some email pleasantries. Let’s do it again, said Barry.

Since then, I’ve had a hard time going back to their neighbourhood. I’m terrified of running into them. I can’t remember what they look like.