Physiological Signs of Tone Deafness?

CNN.com is running a cool story that discusses some brain studies dealing with different senses. There is a section on your sense of direction (not very good), your sense of smell (your nostrils appear to be in competition with each other), and on tone deafness. I found this one very interesting.

My wife and one of my best friends are tone deaf. Jen complains about it now and then. She seems to think that there is something wrong with her because she can't sing in tune. I disagree. My friend Larry is in the same boat, but he was a music minor in college and had to take a course that required a great deal of recognizing different sounds, including pitches. How did he do it? He trained himself. As with everything, practice makes perfect. The more he worked at being able to match pitches with his voice the better he got at it.

This story doesn't go into detail, but it does say that it is possible to teach some one who is tone deaf how to hear specific tones. I knew it all along. It just takes practice.

Here's the segment from the article (I have removed the links)...

Some people are really bad at singing a song they've heard, and scientists are figuring out why.

The phenomenon, called tone deafness, refers to people who do poorly at distinguishing between different musical tones.

Researchers at Beth Israel Deaconess Medical Center and Harvard Medical School in Boston, Massachusetts, looked at images of the brains of 10 people who tested as being tone deaf, and 10 people who were not...

Previous research has shown that people with lesions in the brain pathway that connects perception and motor areas of the brain have trouble with language, said Psyche Loui, instructor in the department of neurology at Harvard University. People with damage to this area tend to have problems with repeating words they hear.

The new study in the Journal of Neuroscience also found that the pathways in this brain area, which usually have top and bottom branches, were implicated in tonal recognition. In fact, scientists could not identify a right-top branch in any of the 10 tone-deaf participants.

"The better you can tell the difference between two tones, the larger that particular brain pathway was," Loui said.

The findings do not mean there is no hope for tone deaf people, however.

"I think there's a lot of music training in general that could help enlarge these pathways," Loui said.

In fact, a treatment for tone deafness might also help people with speech disorders such as dyslexia, she said. There has been evidence that people with dyslexia have same auditory processing problems as people with tone deafness, she said. Her lab showed last year that children with musical training performed better on dyslexia tests.

On the other end of the spectrum, some people have perfect or "absolute" pitch, and can name any musical note they hear. Diana Deutsch, psychologist at the University of California, San Diego, has found people who speak "tone" languages, with words that change meaning entirely depending on tone, seem to have a greater likelihood of perfect pitch. More speakers of Mandarin and Cantonese, two tone languages, tend to have perfect pitch than English, for example, she said.

In theory, in Deutsch's view, it should be as easy to call a pitch "F" as it is to say that an object is red or blue.

"If you assume that there's something missing in our environment in terms of early exposure to the right types of sounds, and that it is bundled in with speech, then the whole thing makes sense," she said.

Practice. Practice. Practice.