Nearly everyone has heard the popular notion that the blind hear better than the sighted – possibly to make up for their inability to see. Now, researchers at the Montreal Neurological Institute (MNI), McGill University and at the Université de Montréal have shown that the blind really do hear notes more precisely but only if they became blind when they were very young. Their findings, Pitch discrimination in the Early Blind, were published in the journal Nature (July 15th).
Dr. Robert Zatorre, a cognitive neuroscientist at the MNI at McGill University, and member of the research team, explained that the idea that blindness can aid musical development is an old one. However, previous studies have not been able to quantify this possibly because they did not take into account the age at which subjects went blind.
In the present study, researchers at McGill and at Université de Montréal tested people from 3 categories: those who were fully sighted, “early blind” (blind at birth or lost their sight during the first two years of life), and “late blind” (those who became blind later in life). The groups were tested for their ability to recognize changes in pitch. The subject listened to a pair of tones and had to decide whether the second tone was higher or lower than the first.
'Early blind' subjects outperformed the other groups in every task, continuing to make correct distinctions as the notes got either shorter or closer in pitch. However, there were no significant differences in performance between sighted and late blind subjects.
These findings reveal the brain's capacity to reorganize itself early in life. At birth, the brain's centres for vision, hearing and other senses are all connected. Pascal Belin at the Université de Montréal and study leader believes that these connections which are gradually eliminated in normal development, might be preserved and used in the early blind to process sounds.Nature News article