Can You Really Stalk Somebody Through Their Eyeball Reflections?

Recently, a stalker found and attacked a Japanese pop star, in part by using an eye reflection to figure out what train station she uses. (He then waited for her at the train station and followed her home.) This got us wondering: how easy is it to get clues about somebody’s location from their selfies?

Before we dive into eyeball reflections, it’s important to note that phones and cameras save extra information in the photo file, including what kind of camera was used to take the photo, whether the flash fired, and (depending on your phone’s settings) a GPS location for where the photo was taken. Some social media platforms may remove location data, but if you’re concerned about privacy, you may want to check your settings to be sure you’re not giving this information away too easily.

To test out the eyeball reflection strategy, fellow Lifehacker staffer Nick Douglas and I took a look at each other’s selfies. We each chose a few that were taken outdoors or in a public place, and stared deeply into each other’s eyes, digitally. It was kind of creepy.

The first thing we learned is that, depending on the lighting and the photo’s resolution, this is not an easy task. Nick summed up the experience pretty well:

1. Zooming into your eyes and staring for clues felt creepy, which will be good to remember next time I worry I’m a psychopath.

2. I can’t see a goddamn thing.

But there are a few clues. In one of Nick’s photos, I thought I saw a reflection of a tree. However, there were also trees behind him in the photo, so “he’s in a wooded area” was not exactly a groundbreaking discovery.

With clearer photos, and a bit of luck, I could see how reflections might give the viewer a clue to where a person is, or in what context they were taking the photo. In one photo where Nick was wearing mirrored sunglasses (too easy, I know) I could tell that he was taking the photo himself, arm raised, and that he was standing on a not-too-busy footpath.

Besides context clues about a person’s surroundings, it seems possible to pick up other information from eye reflections. If the photo was taken by another person, research on high-resolution photos shows that it is possible to identify people from eyeball reflections.

You can also sometimes pick out the shape of light sources — whether there’s a window, or a single light on the ceiling, or a series of them like you’d find in a store.

So, should you worry about how much information you’re revealing in a selfie? Probably not too much… but maybe just a little.