At a crowded tourist site, a young man in a yellow T-shirt angles for a spot on a bench. He sits, removes his backpack, and places it on the ground. After riffling through a blue plastic shopping bag, he walks away, leaving the backpack behind. A few minutes later, a bomb explodes. Twenty people die.

All that’s known about the young man in the yellow T-shirt is contained in a snippet of dim, grainy footage from a CCTV camera. Would anyone recognize his face?

This really happened. Just a couple weeks ago, Thai police launched a search for the young man in a yellow T-shirt, whom they believe blew up Bangkok’s Erawan shrine on August 16. They arrested a man at the Cambodian border and say he matches the description of the yellow-shirted bomber. But based on that grainy footage, they hesitate to say for sure.

View Images This man was spotted dropping a backpack just before the bombing of a Bangkok shrine. Photograph by REUTERS, Thai Police/Handout via Reuters Police captures this image of a man in a yellow shirt dropping a backpack just before the bombing of a shrine in Bangkok. Police captures this image of a man in a yellow shirt dropping a backpack just before the bombing of a shrine in Bangkok.

It’s just this kind of situation that prompted Scotland Yard to form a team of super-recognizers. These London police officers have an amazing ability to recognize and match faces, even from rough CCTV footage.

“Gary Collins is so good that he ID’d three people over his Sunday roast,” says Detective Chief Inspector Mick Neville, speaking about one member of the super-recognizer team who likes to relax on weekends with an iPad loaded with photos of criminal suspects. After London’s 2011 riots, the superrecognizers combed through thousands of hours of footage; Collins alone identified an incredible 190 faces among the rioters. Today, Neville heads London’s central forensic image team, which has tested thousands of police officers and identified 152 super-recognizers. These face-spotting stars normally work in their local stations, building up a mental library of the area’s criminals, and periodically attach to New Scotland Yard to solve crimes.

So far, among their wins they’ve helped to solve the murder of 14-year-old Alice Gross, spotted a serial molester on different city bus routes (he was tracked to particular routes and arrested) and are now working to link at least 30 different thefts, including major art and jewel heists, to one perpetrator.

London’s super-recognizers were out in force at this week’s Notting Hill Carnival, the world’s biggest street fair outside Rio de Janeiro. “We’ve had a lot of problems with crime at the carnival,” Neville says. So super-recognizers sat in CCTV control centers this year and scanned the crowd, where they spotted members of rival gangs edging close to one another. Officers on the scene found and disarmed the men, averting a potential fight. “The senior detective was amazed at their ability to spot suspects in dense crowds,” Neville says.

You might share this superpower, too, and not even know it. The ability to recognize faces, it turns out, falls along a spectrum, says David White of the University of New South Wales’ forensic psychology laboratory. At the lowest end are people who are “face-blind,” a condition called prosopagnosia. (Oliver Sacks, the famous neurologist who recently died, had this condition. He said he recognized his best friend Eric by his “heavy eyebrows and thick spectacles.”) On the other end are super-recognizers.

Most people overestimate their skills, White says. “When people think of face recognition, they think of recognizing people they know,” he says—like spotting a friend in the grocery store. But recognizing the face of a stranger, say from two different photos laid side-by-side: That’s much, much harder.

You can take a test to get an idea of where you fall on the spectrum. Josh Davis, a psychologist at the University of Greenwich, devised both a short, simple test—meant as an extremely rough first pass for fun—and a more detailed test that will help researchers map out how many people fall along each part of the spectrum. (Go here to take the simple test and find a link to the longer test.)

So far, Davis says, it appears that face recognition is an innate ability—not learned, for the most part—and that it’s distributed on a bell curve, like IQ. No particular genes have been linked to the ability, but a 2010 study found that face-recognition ability was very similar in identical twins, compared with fraternal twins, a first indicator of a genetic link to this skill. What’s more, prosopagnosia or “face-blindness” is tied to the fusiform face region, slivers that run along the bottom of the brain near the back of your head. That’s probably a good place to look for evidence of differential brain activity in super-recognizers as well.

View Images London’s police super-recognizers identified Arnis Zalkalns as the potential killer of Alice Gross based on CCTV images. Photograph courtesy of Metropolitan Police/PA Wire

So what percentage of people might be super-recognizers? Davis says that depends where you decide to draw the line, but certainly fewer than 1 percent of people fall into the tail end of the bell curve where the truly exceptional lie.

Next is the question of how to take advantage of people with natural face-sighting superpowers. Detective Neville says that he’s had phone calls from police around the world interested in learning about his team. And White has been working with the Australian passport office to develop tests for face-matching ability and training for passport officers, who in their day-to-day work have to determine whether the stranger in front of them is the same person shown in a tiny passport photo.

In a study published Tuesday in the Proceedings of the Royal Society B, White’s team tested a group of crack forensic examiners who specialize in face image analysis to see whether they would perform better than average, and to begin understanding whether training might help to improve the skills of people who match faces for a living.

The experts, it turned out, did perform better than either untrained students or forensic experts who don’t match faces regularly. (And, by the way, did far better on tasks where facial-recognition computer algorithms typically fail.) Perhaps people with above-average skills gravitated into these positions based on their abilities. But surprisingly, the expert face-matchers showed another ability, unusual in those with “natural” face-matching skills, to identify faces that were shown upside-down. That suggests to White that the experts’ training, which emphasized breaking a face down into component parts and matching each one, may be boosting their skills beyond their natural abilities.

So perhaps there’s still some hope for those who, like me, score a pathetic 7 out of 14 on the simple face-matching test.

A bit murkier, though, is how courts around the world might respond to the introduction of evidence based on a positive ID by a super-recognizer. In the United States, judges use a legal precedent called the Daubert standard to determine whether evidence is scientifically supported, and eyewitness IDs of all sorts have come under scrutiny. But Neville says his team’s matches are usually just the starting point for developing a criminal case, pointing police toward a suspect who can then be investigated using DNA or good old gumshoe police work, in which case the ID is more of an investigative tool than direct evidence of criminal misdeeds.