A study by New Zealand psychology researchers has linked tone deafness with poor spatial skills.
The study, published in the international journal Nature Neuroscience, found that people with tone deafness - known technically as amusia - performed significantly worse at a task requiring them to mentally rotate objects.
Study co-author associate professor David Bilkey of Otago University said true tone deafness affected about 4 per cent of the population.
"It's not just the inability to carry a tune - people with amusia are often simply unable to tell differences between the musical notes they hear," he said.
Dr Bilkey and fourth-year student Katie Douglas investigated whether tone deaf people had deficits in spatial representation and processing, which involves a different part of the brain. The study involved 34 university students, including eight identified as amusical through a standard test.
There were two control groups, one composed of 14 musicians and the other of 12 students from non-musical backgrounds.
When asked to perform a task involving mentally rotating three-dimensional objects made up of cubes - where they try to judge whether pairs of images are the same object rotated or mirror images - the amusical group made more errors than the control groups, Dr Bilkey said.
Two further tests backed up the initial finding, he said.
Dr Bilkey said the findings provided an important insight into the possible causes of amusia.
"We are all used to thinking about tones as being high or low, but these findings suggest that this could be more than just a metaphor.
"It might be based on something more fundamental to do with the way the brain stores information about the high and low notes in melodies."
