Correcting automatically generated closed captions for online learning materials does not improve student learning outcomes (although students believe it does)

Lecture capture is ubiquitous in higher education. Lecture capture recordings are typically accompanied by automatically generated closed captions that are sometimes corrected by humans. Students self-report that they benefit from captions, and particularly human-corrected captions. However, multimedia learning research suggests that simultaneous spoken and written information impairs learning. Experimental tests of the pedagogic benefits of captions in authentic higher education learning contexts are sparse. Consequently, we block randomised 144 undergraduate psychology students to 12 sets of lecture capture recordings with uncorrected, corrected or no captions then assessed their understanding of these materials with 12 quizzes. Our pre-registered analyses indicated that the differences between conditions were trivial (M η² = 0.01; | M | δ = 0.12) and that the captioning conditions to which students were randomised did not influence their quiz performance. Follow-up surveys re-confirmed that students believe captions are beneficial for multiple reasons (eg, improved comprehension and focus; study efficiency; accessibility), and prefer corrected over uncorrected captions, even though they do not always notice the difference. As they do not impair learning, do meet accessibility requirements and are valued by students, automatically generated captions should be used routinely. However, correcting them may not reflect an optimal use of resources.