Researchers used EEGs (electoencephalogram) to measure the brain’s reaction to simultaneously played pairs of high and low sounds. Changes in timing were easier to perceive in the low sounds than in the high ones. (Credit: Elaine Whiskin)
A new study helps explain why, in musical cultures from around the world, rhythm is usually played on low-voiced instruments while pitch is played on high-voiced ones.
It turns out that when two sounds are played together, the human brain perceives timing differences in low-pitched sounds more easily than those in high-pitched sounds.
In the study, 17 subjects were presented with a steady pattern of simultaneous high-pitched and low-pitched tones, but occasionally one of the tones was played 50 milliseconds ahead of the other. EEG scans showed that the auditory cortex of the brain registered the mismatch more strongly when the low tone was the one that was mistimed.
The research complements earlier work which showed that pitch is easier to perceive in higher tones.
Original research paper published in the Proceedings of the National Academy of Sciences (USA) on June 30, 2014.
Names and affiliations of selected authors
Laurel Trainor, McMaster University, Ontario
Ian Bruce, McMaster University, Ontario
