The effect of motion on crowding: zooming text.

Crowding is the major sensory factor responsible for the slow reading speeds exhibited in peripheral vision. Past attempts to improve peripheral reading via crowding reduction have generally focused on applying spatial changes to the stimulus and have been largely ineffective. Recent evidence indicates that dynamic approaches have good potential for reducing crowding in peripheral reading. We tested this hypothesis by introducing "zooming" motion (smooth letter resizing across the presentation duration) to trigram stimuli (groups of three randomly selected letters) presented at 10° in the lower visual field and evaluating recognition of the middle letter. Crowding was alleviated in the presence of this motion, both when dynamic cues were introduced to all letters in the trigram simultaneously and when they were applied to individual letters alone. The magnitude and direction of crowding reduction depended on the amplitude and direction of motion. These results suggest that dynamic presentation may be a useful tool for improving peripheral reading through reducing letter crowding. Zooming motion, in particular, has the additional advantage of conserving text layout, making it a good candidate for such an application.