10 Subtle Tricks Horror Movies Use To Scare You

The third and final application of the so-called uncanny valley for horror filmmakers, mirrors and doubles crop up constantly in horror. Candyman and Bloody Mary appear through them (alongside crappy remake Freddy Krueger and South Park's Biggie Smalls). Characters are forever seeing their own reflections distort and change in them before their eyes.

And this isn't even mentioning the many, many characters who have seen a threat appear behind them through the medium of mirrors (do furniture manufacturers even make mirrored bathroom cabinets any more or do they only ever appear in cliched horrors?).

The reason for this may be clear to many readers but for those who aren't in the know, mirrors are naturally sources of fear for people because of the limited human capacity for self identification. The simplest iteration of this phenomenon is the classic sleepover game Bloody Mary, a psychological trick which relies on players focusing on their unchanging, unmoving reflection for long enough that the eyes begin to distort and subvert what they're seeing.

That's why mirrors are so often the locus of scary scenes as viewers have an innate distrust of the flat, two dimensional unreality of reflections and as such expect them to hide something sinister.