Abstract Asynchronous video lectures are regularly used in higher education, and students are commonly able to manipulate playback of these videos by adjusting playback speed and turning on closed captioning. The impact of these types of adjustments on student learning has been studied in a few fields, but additional study of the topic is needed, and the combination of the use of captions with video speed adjustments has only been minimally evaluated. In this study, we used a survey with embedded short lecture videos at controlled playback speeds (1x, 1.25x, 1.5x, and 2x), with or without auto‐generated captions, followed by short quizzes to evaluate the impact of video speed on short‐term retention. The assessment was completed by 468 students in an introductory soil science course, with videos focused on soil science concepts at an upper‐division undergraduate level. Most students reported that they habitually turn on captions and increase playback speed for lecture videos, with 1.25x being the most commonly reported speed. We found that in some, but not all cases, increasing playback to 2x speed had small but significant negative impacts on student performance on post‐video quizzes relative to 1.5x speed, but there were no negative impacts up to 1.5x speed. The addition of auto‐generated captions did not impact learning outcomes, and there were no differences as a function of gender, year in school, or video playback habits. We conclude that increasing playback speed for video lectures is unlikely to have major negative impacts on student learning.
Rees et al. (Fri,) studied this question.