Our bodily functions cyclically change along with environmental rhythms, like light and dark, and this in turn governs our perceptions and our behaviour. Likewise, our hearing ability also changes.
Researchers Molly Henry and Jonas Obleser from the Max Planck Institute in Germany have discovered that our hearing depends on the exact timing of our brain's rhythms.
Our brains, sound and behaviour are therefore connected and coupled and our brain activity consequently influences the way we listen.
The research shows that the rhythms in the environment, rhythms in the brain as well as our behaviour are all coupled together and influence one another.
The research therefore confirms that the world is full of cyclic phenomena that change through the course of each day.
The listening brain
The German researchers have also investigated the idea of â€œthe listening brainâ€, which involves the way in which humans process speech and music. If the brain is coupled to melodic changes, then it may also be better prepared to expect fleeting but important sounds in what the voice is saying.
In the study, test persons were exposed to a hard-to-detect silent gap embedded in a melody. Henry and Obleser then recorded the signals from the test personsâ€™ scalps.
First, the study proved that every test personâ€™s brain was â€œpulled alongâ€ by the slow cyclic changes in the melody. Second, the test personsâ€™ ability to discover the gaps hidden in the melodic changes was not constant, but was instead oscillating as it was governed by the brain.
The oscillating brain activity governs and regulates our ability to process incoming information and is called neural oscillations.
All acoustic fluctuations that humans encounter thereby appear to shape our brain activity. The brain uses the rhythmic fluctuations to be best prepared for processing important upcoming information.
The researchers hope to be able to use the brain's coupling to its acoustic environment as a new measure to study the problems of listeners with hearing loss or people who stutter.