It's the basis for, like, 90% of jump scares in horror movies: The victim looks around, certain they feel someone watching them, and once they've assured themselves they're imagining things, they get extra-murdered.
But that's a real thing that everyone has experienced (the eerie feeling that someone is watching you; most people are lucky enough to live a stab-free life). So how does that even work? Did we just convince ourselves we could do that because we saw it in so many horror movies? Which came first, the chicken or the trope?
It turns out you're not inventing that "reminder to go to the barber about those hairs on the back of your neck" feeling. It's not some kind of sixth sense thing, though, just one of the boring big five: the miracle of the human eye. It's a system so finely tuned that it's one of the more successful arguments for intelligent design, to the point that we can see someone looking at us even when we're not looking at them. We can pinpoint it with such accuracy that if the person's gaze is even a few degrees off, you won't get the spine tingles. Even blind people can do it as long as they have something called "cortical blindness," which means their brains still receive input from their eyes even if they can't consciously perceive it. The person looking at you just has to be anywhere in your field of vision, which is wider than you probably think:
That means you don't have eyes in the back of your head, just really good ones in the front. If you do catch someone staring at you who was truly outside your field of vision, it's likely they looked at you because they sensed you looking at them. Or they farted softly. You do have other senses.
Top image: Unsplash/Oleksandra Bardash