The impact of subtitle speed and number of lines on saccadic latency: An eye-tracking study ETRA025

This eye-tracking study examines saccadic latency during subtitled video processing, i.e., the time to shift attention from the video image to the subtitle, based on subtitle speed (145 vs. 180 words per minute–wpm) and number of lines (one vs. two). We employed a mixed-design experiment with deaf (N=20) and hearing (N=20) participants, making use of a linear mixed-model regression for analysis. While the group difference was not statistically significant, the results revealed a significant interaction between subtitle speed and number of lines: at fast speeds (180 wpm), subtitle line count did not affect latency, yet at slow speeds (145 wpm), two-line subtitles incurred a significantly shorter latency. These findings indicate that two-line subtitles, especially at slower speeds, reduce processing latency, which may preserve more time for actual text comprehension.