How well do you know your target audience? Can you sit in an airport, and as a whole world of people from different backgrounds and with different interests walk by, can you pinpoint those who might be your ideal customer? If so, how would you do it?

Maybe they are carrying a briefcase or an expensive purse; maybe they wear a certain brand of shoes or sport facial hair. It turns out, certain characteristics and accessories visually clue us in on social identities and subcultures, or what sociologists call “urban tribes.” Without really meaning to, we categorize people into these urban tribes—think hipsters, bikers, goths, surfers—by their outward appearance, which includes their fashion choices. Whether or not we want to be labeled, if we dress like a certain population, outsiders may target us as a member of a particular tribe.

So why does this matter? A recent article in The Atlantic Cities covered research from a group of computer scientists who have developed an algorithm capable of identifying these groups from photography. Photos from the project were disassembled into various parts—head, torso, arms, face—while the algorithms read the details from images—beard, tattoo, surfboard, motorcycle—to piece together a social identity.

The possibilities for this kind of targeting in the paid media world are exciting; especially with the prevalence of personal photo sharing sites like Facebook and Instagram and consumers’ increasing comfort with targeted advertising in their news feed.

As scary as this type of targeting may sound, the more data we have on consumers, the better we can serve up advertising that resonates with right audience.