Did you hear that voice? It could be your brain looking for patterns

As many as 15% of the population experience auditory hallucinations. This could mean hearing sirens, or a dog barking, or someone talking, when in fact nothing is there. Most people just call this "hearing voices". Most of these people never need to access mental health services.

A recent study from Durham University in the United Kingdom looked at the ability of people who experience these hallucinations to detect voices hidden by noise. The researchers, including lead author Dr. Ben Alderson-Day, had voice hearers and non-voice hearers lay in an MRI and listen to recordings that contained people's voices converted into sine wave tones. While these sounds can be understood, it isn't immediately apparent that they are actually voices.​

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What they found was that people who experience auditory hallucinations were more likely to detect the hidden speech, and noticed the voices faster. Dr. Alderson-day says that one possible explanation for this is the theory that our prediction of reality affects how we experience and perceive reality. He says that "a lot of the time, what our brain is doing when it's taking in information from the environment around us is making its best guess or prediction, trying to fit a meaningful pattern to those signals that make sense of the world for us. 

"The idea is that maybe for the people who hear voices, actually their brains are doing this more than others. They're looking for meaningful patterns, they're trying to find the signal amidst the noise."

Paper in the journal Brain, "Distinct processing of ambiguous speech in people with non-clinical auditory verbal hallucinations"