Normally means a ratio of 3:1 (or 0.75:0.25) between the two notes. However, many sources seem to imply that in French overtures or other genres where such rhythms are predominant, this ratio should be altered to , i.e. 7:1 (or 0.875:0.125). During the 1960-70s Frederick Neumann stirred up a controversy by questioning the validity of such exaggerated interpretations.
Emery Schubert and Dorottya Fabian introduced a new perspective when they examined the problem empirically. They conducted acoustic measurements of commercial recordings of such pieces and tested listeners’ perception of variously performed dotted patterns. In the course of their investigations they discovered the kerning illusion and showed that contrary to the musicological argument, perceived dotting ratio has a relatively minor role in creating perceived musical character: Articulation, tempo and loudness play a more crucial part.
Fabian, D. & Schubert, E. (2010). A new perspective on the performance of dotted rhythms. Early Music, 38(4), 585-588. doi:10.1093/em/caq079
Fabian, D. & Schubert, E. (2008). Musical character and the performance and perception of dotting, articulation and tempo in recordings of Variation 7 of J.S. Bach’s Goldberg Variations (BWV 988). Musicae Scientiae, 12(2), 177-203.
Fabian, D. & Schubert, E. (2003). Expressive devices and perceived musical character in 34 performances of Variation 7 from Bach’s Goldberg Variations. Musicae Scientiae, Special Issue 2003-2004, 49-68 (abstract)
Schubert, E. & Fabian, D. (2001). Preference and perception in dotted 6/8 patterns by experienced and less experienced baroque music listeners. Journal of Music Perception and Cognition, 7(2), 113-132 (abstract)
A preliminary report on the comparison of acoustically measured and subjectively judged performance parameters was presented at the Conference on Interdisciplinary Musicology (CIM04), 15-18 April 2004, Graz (Austria). The results confirm the dotting illusion and the more significant contribution of articulation and tempo (both measured and perceived) to musical character.