Asymmetry of the effective visual field in reading.

Abstract

In three experiments, subjects’ eye movements were recorded as they read from a computer-controlled CRT. The amount of information available to the left and right of the fixation point was varied in order to determine the characteristics of the effective visual field in reading. Experiments 1 and 2 demonstrated that readers do not obtain useful information during a fixation more than 3 or 4 letters to the left of their fixation point. The results of Experiment 3 indicated that the effective visual field does not extend any further to the left than the beginning of the word currently fixated, independent of the number of letters available to the left of fixation. When combined with the results of other research on the perceptual span in reading, the results of these experiments indicate that the effective visual field extends from the beginning of the currently fixated word (but no further than 4 characters to the left of fixation) up to about 15 characters to the right of fixation.