Why do people hear their names being called in the woods?

You're walking through the woods with no one else around when you hear it: Faintly, from the background hum of the forest — impossibly, hair-raisingly — comes the sound of someone calling your name.

Could it be a ghost? Bigfoot? Some elaborate practical joke by a prank TV show? It's likely none of those — so why do people sometimes hear their names or other words being called when no one is actually saying anything? And is it ever something to worry about?

The phenomenon of hearing intelligible voices or noises in meaningless background noise is known as "auditory pareidolia." The sources of this noise vary; they may include electric fans; running water; airplane engines; the hums of washing machines; or white-noise machines, according to audiologists. It is an auditory sub-type of pareidolia, in which people see faces or other meaningful patterns in ambiguous images.

Auditory pareidolia isn't considered a type of auditory hallucination, which occurs when a person hears sounds that don't exist in reality and transpire appear without any external stimulus, such as white noise. Such hallucinations are common in various mental conditions, including schizophrenia, post-traumatic stress disorder and bipolar disorder. Non-psychiatric hallucinations have also been reported by those with hearing loss, although the condition, known as musical ear syndrome, is relatively rare and understudied. 

But people with and without these conditions can experience auditory pareidolia, which emerges specifically from background noise.

Related: Why do people feel like they're being watched, even when no one is there?

But why does auditory pareidolia happen in the first place?