In infants' song Infants experiment with singing, and a few studies of individual infants' singing found that neutral thirds regularly arise in their improvisations. In two separate case studies of the progression and development of these improvisations, neutral thirds were found to arise in infants' songs after major and minor seconds and thirds, but before intervals smaller than a
semitone and also before intervals as large as a
perfect fourth or larger.
In modern classical Western music The neutral third has been used by a number of modern composers, including
Charles Ives,
James Tenney, and
Gayle Young.
In traditional music Claudius Ptolemy describes an "even diatonic" tuning which uses two justly tuned neutral thirds in
Harmonikon built off the 12:11 and 11:10 neutral seconds in compound intervals with 9:8 and 10:9 whole tones, forming the intervals: (12/11)*(9/8) = 27/22, (11/10)*(10/9) = 11/9. The latter of these is an interval found in the
harmonic series as the interval between partials 9 and 11. The equal-tempered neutral third may be found in the
quarter tone scale and in some traditional
Arab music (see also
Arab tone system). Undecimal neutral thirds appear in traditional
Georgian music. Neutral thirds are also found in American folk music.
In contemporary popular music Blue notes (a note found in
country music,
blues, and some
rock music) on the third note of a scale can be seen as a variant of a neutral third with the tonic, as they fall in between a major third and a minor third. Similarly the blue note on the seventh note of the scale can be seen as a neutral third with the dominant. == In equal temperaments ==