  Technical progress in hardware and software enables us to record gaze data in
everyday situations and over long time spans. Among a multitude of research
opportunities, this technology enables visualization researchers to catch a
glimpse behind performance measures and into the perceptual and cognitive
processes of people using visualization techniques. The majority of eye
tracking studies performed for visualization research is limited to the
analysis of gaze distributions and aggregated statistics, thus only covering a
small portion of insights that can be derived from gaze data. We argue that
incorporating theories and methodology from psychology and cognitive science
will benefit the design and evaluation of eye tracking experiments for
visualization. This position paper outlines our experiences with eye tracking
in visualization and states the benefits that an interdisciplinary research
field on visualization psychology might bring for better understanding how
people interpret visualizations.
