Bring the noise
Not everyone can hold a perfect tune. Some can’t but don’t really care, while some – such as tone- or tune-deaf people – can’t actually tell they are out of tune
True tone deafness (or amusia) affects about 5 per cent of the population. Generally, people with amusia cannot perceive music normally because of an underlying deficit in processing pitch and melody. It seems to be linked to characteristic brain abnormalities, including fewer ‘white matter’ connections between different areas of the brain.
Some people with amusia still enjoy music. For others, though, music is just a cacophony – as one person put it, “like pots and pans falling on a stone floor”. Amusia may develop after head injuries or strokes, but in most cases people are born with it.
Perception of a bum note triggers two characteristic types of electrical activity in the brain. Interestingly, one of these signals is also seen in tone-deaf people, suggesting that their brains have spotted the discordant note even though it does not register consciously.
Less often, people with amusia can hear tones but cannot hear any meaning in a sequence of notes – a melody. Others lack only the ability to distinguish timbre. Some specifically cannot perceive dissonant tones. Intriguingly, these people typically have lesions in the brain area involved in emotional judgements.Lead image:
Son_gismo/Flickr CC BY