The objective: Relative pitch, the ability to sing in tune, relies on hearing notes correctly, measuring their intervals, storing the information in memory, and producing the tones. I am trying to understand what leads to atonality, the inability to carry a tune. It is possible that the Atonal individual does not hear notes correctly or even that the two ears hear conflicting notes. In this case, one ear could be dominant, or the resulting sound could be a blend of what the individual ears hear. By testing the ears separately and together in a tone matching test, I can discover whether Atonal individuals have a defect in one or both ears that affects how they sing.
I obtained informed consent from 62 participants, including 25 males and 37 females, ranging in age from 13 to 76 years. I collected information, including handedness, musical training, self-evaluation of singing ability, eye dominance, and hair whorl direction. I measured relative pitch capability with a chromatic tuner while subjects sang a simple melody (measuring 10 notes x 3 replicas). Next, I tested their tone matching ability using a test CD played with a splitter jack, so that the earphones could play the tones for individual ears or both at once. I again measured their vocalized tones (5 notes x 3 replicas x 3 sets). Notes were converted into numbers and graphed to determine phenotypes.
Most Atonal subjects scored poorly in tone matching. Surprisingly, however, more than one third had excellent scores in the Tone Matching Test. This means that hearing tones well is not enough to carry a tune. Left and right ears differed in more than one third of the participants, mostly in those with poor tone matching ability. I found ear dominance in approximately 30% (7 of 24) of those with poor tone matching ability, but in less than 10% of those with excellent tone matching skill. The sidedness of ear dominance (left vs. right) did not correlate with hair whorl, eye dominance, or hand dominance.
My hypothesis is partially correct. Hearing conflicts and ear dominance may influence the perceived tone in a significant portion of Atonal individuals. Since more than one third of the Atonal subjects have excellent tonal hearing, I conclude that tone matching and interval measuring are independent skills.
This project discovered that there is often an apparent difference in what the right and left ears hear in Atonal individuals.
Science Fair Project done By Miriam C. Glicksberg