One of the most fascinating things I’ve found out running this web site is the large variance in what people can perceive. My own ears are hypersensitive to some noises and hypo-sensitive to others. My eyes are also more light sensitive than many other peoples. Its entirely possible that many of the problems of dyslexia, ADHD and conditions on the autistic spectrum are caused by the suffers having extreme over or under sensitivity to light, sound, touch, taste and smell. We all assume that other people perceive the world in the same way we do but this is not the case. If we can understand how the suffers’ interact the world we may be able to make sense of the suffers’ behavior. The child who throws a tantrum when having his hair cut may not just be acting up but be genuinely distressed by the feel of the scissors, the sound of the blades or the proximity of the hair dresser.
A great example of the huge spectrum of sensitivities is this report into the ‘Bristol Hum’. A number of people had reported a constant low pitch humming noise which was making their life a misery and led to the suicide of one person who was unable to cope with the constant noise. British Gas investigated, suspecting that it might be caused by its equipment. It found that in 80% of the people the source was hearing problems but 33 people were found to be genuinely hearing a hum which could be detected by sensitive electronic equipment. British Gas managed to track the source of one persons noise to resonance in its pipe work but the the rest were traced to a various sources such as industrial refrigerators up to 5 kilometers away.
So sounds that no else can hear were making life a misery for highly sensitive people up to 5km away and were bad enough to drive one person to suicide. What effect would these noises have on a small child?
More about the problem of background hums: The Hum including a brief snippet on ADHD and The Hum, Taos Hum Home page , Right to Quiet Society, UK Noise Association (they are against it).