Life’s 10 most unpleasant sounds
A new study published in the Journal of Neuroscience has come up with a list of the least pleasant sounds we encounter in everyday life, with the aim of better understanding conditions like migraines that are affected by sound.
Lead study researcher, Professor Tim Griffiths of Newcastle University, wrote in the report, “Shedding new light on the interaction of the amygdala and the auditory cortex might be a new inroad into emotional disorders and disorders like tinnitus and migraine in which there seems to be heightened perception of the unpleasant aspects of sounds.”
Using 13 volunteers, researchers tested reactions to 74 common noises for outward response as well as for small brain changes. The results showed that anything acoustically in the frequency of 2,000 to 5,000 Hz was unpleasant to the human ear.
Study author Dr Sukhbinder Kumar noted this range was unsurprising, writing “This is the frequency range where our ears are most sensitive. Although there’s still much debate as to why our ears are most sensitive in this range, it does include sounds of screams which we find intrinsically unpleasant.”
The study was funded by Wellcome Trust, and took place at the Centre for Neuroimaging at University College in London. Researchers used functional magnetic resonance imaging to see how the volunteers brains reacted to sounds as varied as a knife on a bottle – which the study found to be the most unpleasant – to babbling water – which proved to be the most soothing.
The results showed a pattern in the connections between the part of the brain that processes sounds known as the auditory cortex, and the amygdala – which processes negative emotions when we hear unpleasant sounds. The amygdala controls the response from the auditory cortex, heightening activity and provoking a negative response.
This information can help doctors form a better understanding of medical conditions where a patient has a decreased tolerance of sound, such as migraines, tinnitus, hyperacusis, misophonia (which is literally a ‘hatred of sound’) and autism.
The top 10 most unpleasant sounds were:
-Knife on a bottle
-Fork on a glass
-Chalk on a blackboard
-Ruler on a bottle
-Nails on a blackboard
-Squealing brakes on a bicycle
While the most pleasant sounds were found to be:
Sources: The Journal of Neuroscience, Guardian, WebMD