Disturbed by harsh, loud noises like that car alarm that always seems to spring into action in the middle of the night or the perfectly pitched screams of the kids running around on the playground? You’re not alone. In fact, it may be a natural response in human beings according to some of the latest research from the University of Geneva (UNIGE) and Geneva University Hospitals (HUG) in Switzerland. But what does it all mean?
Harsh noises and human response
We know that certain loud noises can immediately make us uncomfortable, maybe even frustrated. Just think back to how you’ve felt frantically waving cooking smoke away from a blaring smoke detector willing it to stop making that noise. It’s a different feeling than other loud sounds, and it’s this difference that intrigued researchers. In search of answers, neuroscientists at the University of Geneva (UNIGE) and Geneva University Hospitals (HUG) in Switzerland teamed up to study people’s responses to different sounds.
The team worked with a small group of 16 individuals playing repetitive sounds between 0 and 250 Hz for them. The sounds were played closer and closer together as the individuals rated them. Luc Arnal, a researcher in the Department of Basic Neurosciences in UNIGE’s Faculty of Medicine specified, “We then asked participants when they perceived the sounds as being rough (distinct from each other) and when they perceived them as smooth (forming one continuous and single sound).”
What they found as they mapped out the sounds and individuals’ discomfort with them was that not all sounds are created equal.
During the study, the team found that certain sounds activated not only the sound processing areas of the person’s brain but also cortical and sub-cortical areas that process aversion. The researchers found that the sounds causing this response were generally between 40 and 80 Hz. Unsurprisingly, sounds like alarms and baby screams can be found in this range of sound. These are repetitive sounds that require our immediate attention, often for safety and survival reasons.
Participants’ feelings and ratings of the sounds weren’t the only way the research team investigated the effect of certain sounds on the brain. The team also used an intracranial EEG to record brain activity. Areas of the brain not usually involved in processing sound, such as the amygdala and hippocampus, were activated, explaining the discomfort.
“We now understand at last why the brain can’t ignore these sounds. Something particular happens at these frequencies,” said Luc Arnal, a researcher in the Department of Basic Neurosciences in UNIGE’s Faculty of Medicine
What do these findings mean? Many of us are well aware that loud and high-pitched alarms and screaming babies have little trouble capturing our full attention. Still, the research team believes there may be more opportunity to be found in the results, specifically in early detection of certain illnesses such as Alzheimer’s and autism where certain sound levels can cause discomfort.
Whatever the noise or sound level, it’s so important to make hearing health a priority. Have routine hearing evaluations and, if you’re diagnosed with hearing loss, take steps to manage it.
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