The phenomenon of hearing intelligible voices or sounds in background noise is called “auditory pareidolia”.
According to audiologists, the sources of this noise in everyday life can be various: electric fans, running water, airplane engines, the hum of washing machines and others. A slightly better-known subtype of visual pareidolia is when people see faces or other meaningful patterns in ambiguous images.
Auditory pareidolia is not considered a type of auditory hallucination. They are considered to occur when a person hears sounds that do not exist in reality and appear without any external stimulus, such as white noise.
Such hallucinations are common in a variety of mental illnesses, including schizophrenia, post-traumatic stress disorder, and bipolar disorder. However, people with and without these conditions can experience auditory pareidolia, which is caused precisely by background noise.
“Think of your brain as a big database of patterns. All the words you know and have ever heard in your life are there. The brain chooses what it thinks is the best template. That best model might not be the right fit at all. In fact, it may be completely inappropriate,” Neil Bauman, an audiologist and CEO of the Hearing Loss Center in Washington, D.C., told Live Science.
The sounds that a person hears when experiencing auditory pareidolia are not completely invented by our brain. Rather, they result from misperceptions of real sounds, such as an unexpected spike in static or background noise coming from the forest.
“The patterns of most noise sources are constantly changing. Let’s take white noise – it will have certain “points” where the pattern will diverge slightly. That may be enough for a person to “recognize” something, Andrew King, director of the University of Oxford’s Center for Integrative Neuroscience, told Live Science.
A. King explains auditory pareidolia by the fact that our brain is constantly trying to understand the world around us and find recognizable patterns in it. It is especially likely to occur when slightly recognizable sounds are masked by the background of a noisy environment such as a restaurant or bar.
In these cases, the brain uses a process called contrast gain control to adjust the sensitivity of brain cells that respond to auditory and visual input so that they can adapt to the continuous incoming signals.
