Ann...
I am less than 2 weeks from defending my dissertation on the design and use of virtual field environments in teacher education in geology, so the question you are asking is a familiar one. Though I don't remember the specific research that you are talking about, here are a few references for some similar research.
Callahan, C. N., Petcovic, H., Baker, K., M., and Libarkin, J., 2009, TRACKING EXPERT AND NOVICE GEOCOGNITION DURING FIELD MAPPING, Geological Society of America Annual Meeting: Portland, OR, Geological Society of America.
Choi, C., 2010, Expert Education - A field study tries to see how expertise can be taught to novices, Scientific American, Nature America.
Petovic, H. L., Libarkin, J. C., and Baker, K. M., 2009, An Empirical Methodology for Investigating Geocognition in the Field: Journal of Geoscience Education, v. 57, no. 4, p. 316-328.
Riggs, E. M., 2009, Assessing Learning Outcomes in Field Geology Instruction, GSA Annual Meeting: Portland, OR.
Most of this list involves studies of student / geologist navigation in the field, though I do remember some of these folks talking about doing some eye tracking work as part of their work. The Choi article, though gray literature, is probably most germane to what you are interested in. The article is about some eye-tracking work involving student fieldwork being done by the folks at Rochester Institute of Technology - Center for Imaging Science. While they have yet to publicize a journal article on this work, they do have a website describing the project < http://www.rit.edu/news/story.php?id=47600 >. The person I talked with there was Jeff Pelz. One other possible source of information would be the Spatial Cognition Conference that took place here in Oregon in 2010 < http://www.spatial-cognition-2010.com/ >. Apparently during that conference there were a couple of talks that were given that are related to your question...
Josh Cohen (a doctoral student for ASU) presented results from eye-tracking experiments involving undergraduates and experts examining field photographs.
Ken Forbus (Northwestern U) discussed novice and expert sketching of geologic features from an outcrop photo.
This was a conference I wasn't able to attend it, so I'm not sure if either of these folks have done any work with eye-tracking in the field, or if anyone talked about this during the conference. But this might be another avenue to investigate.
Hope this helps
Cheers
Frank G.
Frank D. Granshaw
Earth Science Instructor
Portland Community College
Sylvania Campus
Portland, OR
503-977-8236