Eye-Movement Parameters and Perceived Map Complexity—II

In part I of this study, it was concluded (Castner and Eastman 1984) that eye movements are an outward manifestation of visual/cognitive processing, and that studies of how, rather than where, the eye moves might prove useful in map-design experiments. Two eye-movement parameters, fixation duration (indicating depth of cognitive processing) and interfixation distance (indicating extent of peripheral processing) reflect the ease with which a display's information can be assimilated. In part II, we describe a twelve-map experiment that confirms the hypothesized correlation between perceived complexity (assessed by 38 subjects) and imageability (indicated by the fixation durations and interfixation distances of 22 subjects), demonstrating the value of eye-movement studies in assessing the holistic properties of maps.