Stable individual differences in saccadic eye movements during reading, pseudoreading, scene viewing, and scene search.

Mean fixation duration and mean saccade amplitude during active viewing tasks differ from person to person. Previous studies have shown that these individual differences tend to be stable across at least some tasks, suggesting that they may reflect underlying traits associated with individuals. However, whether these individual differences are also stable over time has not been established. The present study established stable individual differences in mean fixation duration and mean saccade amplitude across 4 viewing tasks, showed that the observed individual differences are stable over several days, and extended these results to standard deviations of fixation duration and saccade amplitude. The results have implications for theories of eye movement control and for using eye movement characteristics as individual difference measures.