This is a rather unique study that I haven't seen before done to people who are tackling physics problems. They tracked the eye movement of the participants in dealing with a particular physics problem, and they noticed differences on the area of focus between those who are just learning physics versus those who are already experts/physicists.
Abstract: This study investigated how visual attention differed between those who
correctly versus incorrectly answered introductory physics problems. We
recorded eye movements of 24 individuals on six different conceptual
physics problems where the necessary information to solve the problem
was contained in a diagram. The problems also contained areas consistent
with a novicelike response and areas of high perceptual salience.
Participants ranged from those who had only taken one high school
physics course to those who had completed a Physics Ph.D. We found that
participants who answered correctly spent a higher percentage of time
looking at the relevant areas of the diagram, and those who answered
incorrectly spent a higher percentage of time looking in areas of the
diagram consistent with a novicelike answer. Thus, when solving physics
problems, top-down processing plays a key role in guiding visual
selective attention either to thematically relevant areas or novicelike
areas depending on the accuracy of a student’s physics knowledge. This
result has implications for the use of visual cues to redirect
individuals’ attention to relevant portions of the diagrams and may
potentially influence the way they reason about these problems.
You should be able to get a copy of the paper for free at the link above.