Consistency of the first fixation when viewing a standard geometric stimulus

Abstract

Eye movements in response to presentation of a standard geometric figure (Rey Complex Geometric Figure) were investigated in 33 normal subjects. The figure was presented to each subject for 20 s, with instructions to remember as much detail as possible. Stimulus display was managed by special software that ensured all subjects were focused on the centre of the monitor before presentation, thus controlling for the initial point of gaze. Subjects were instructed, after viewing the stimulus, to reproduce the figure to scale on a blank sheet of paper. Location of the first voluntary fixation during the viewing period was consistently near the same feature in 80% of subjects (cohort I, n = 20). Patterns of eye movement during the remainder of the period, however, were found to vary widely among individuals. A complementary experiment using a second group of subjects (cohort II, n = 13) was undertaken to examine possible effects of brain function lateralisation on processing a feature in the left hemi-field. No lateralisation effect was evident and consistent identification of the same feature in the first voluntary fixation was confirmed for all subjects. No systematic relationships were found between eye movement indices obtained from real-time viewing of the Rey Figure and subsequent recall by drawing.