"The effects of skill on the eye-hand span during musical sight-reading"

The article by S. Furneaux and M.F. Land (Sussex for Neuroscience, University of Sussex, Falmer, Brighton BN1 9QG, UK) is one of the very few papers written about sigh-reading dual-staved scores since the 1940s. Weaver (1943) and Van Nuy & Weaver (1943) have looked into sight-readers reading two staves. Sloboda (1974) and Truit at al (1997) both have looked into single-staved scores and sight-readers. Sloboda looked into *EHS of pianists without looking and measuring eye movement. His results are likely to be overestimated (we will discuss it later).
This paper is unique because it measures EHS in *note index, *time index as well as the*time delay aspect of sight-reading.
The results were:
"- professionals showed a 4 notes index versus the amateurs who showed a 2 notes index
- the time index varied with tempo therefore, the length of time that information is stored in the musicians *buffers is related to performance tempo rather than skills, but that professionals can fit more information into their buffers."
It is a fascinating article that shows the zig-zag movement of the pianist's eyes in very informative graphs (you should take a look at them). Ot was found that pianists do not read the two staves together. I realize that my theory of us pianists having to make choices as we sight-read is very likely since our eyes zig-zag and move not only horizontally, but vertically. I would like however, to find an article about these abilities to make choices where two pianists are analyzed while sight-reading the same score. What king of zig-zag is more effective?

*EHS = eye hand span
*note index = number of notes between hand and eye
*time index = time between fixation and performance
*time delay = how long the information is stored before the actual performance
*buffer = a temporary memory area used when transferring data between devices and programs operating at different speeds