There is a large amount of research showing that captioned videos can help students of all ages improve their literacy -- and also better retain the video content and ultimately get better grades. We've summarized some of it here. Links to abstracts have been provided in the citations.
Captioned video can help readers of all ages, from emerging readers1,2, to middle schoolers3, to adolescents9, to college students10,13, to adults4,5,7. It's especially helpful for those who are reading below their grade level2, who have learning disabilities6, or who are ESL/ELL students3,8.
Students enjoy watching captioned videos6,7,9, so it's also a great way to motivate reluctant or struggling readers. College students prefer video lectures that include captions11.
You don't have to use long videos or show a lot of them. Even watching short clips of captioned educational videos - ranging from 1.5 to 8 minutes long - every few days improved reading skills significantly1,3,6.
The specific areas that captioning can improve include word recognition, word comprehension, vocabulary, identifying the main idea of a story, phoneme recognition, listening comprehension, and oral reading skills1,2,3,4,6,8,12.
Captioning also helps students understand and retain more of the concepts presented in the video3,11,13, remember more of the dialogue of a film14, take better notes10,11, and participate more in class discussions of video content10, making it a great tool for teachers of any subject at any level!
1 Linebarger, Deborah L. (2001). Learning to Read from Television: The Effects of Using Captions & Narration. Journal of Educational Psychology, 93(2), 288-298. Abstract
2 Linebarger et al (2010). On-screen print: the role of captions as a supplemental literacy tool. Journal of Research in Reading, Volume 33, Issue 2, 148-167. Abstract
3 Neuman, S., & Koskinen, P. (1992). Captioned Television as Comprehensible Input: Effects of Incidental Word Learning from Context for Language Minority Students. Reading Research Quarterly, Vol. 27, No. 1 (Winter, 1992), 94-106. Abstract
4 Griffin, R. & Dumestre, J. (1993). An initial evaluation of the use of captioned television to improve the vocabulary and reading comprehension of navy sailors. Journal of Educational Technology Systems, Volume 21, Number 3 / 1992-1993, 193-206. Abstract
5 Koskinen et al (1995). Captioned Television and the Vocabulary Acquisition of Adult Second Language Correctional Facility Residents. Journal of Educational Technology Systems, Volume 24, Number 4 / 1995-96, 359-373. Abstract
6 Koskinen et al. (1986). Using Closed Captioning to Enhance Reading Skills of Learning Disabled Students. National Reading Conference Yearbook, Vol 35, 1986, 61-65. Abstract
7 Bean, R. M., & Wilson, R.M. (1989). Using Closed Captioned Television to Teach Reading to Adults. Reading Research Quarterly, Volume 28, Issue 4, 27-37. Abstract
8 Huan, H-C, & Eskey, D.E. (1999). The Effects of Closed-Captioned Television on the Listening Comprehension of Intermediate English as a Second Language (ESL) Students. Journal of Educational Technology Systems, Volume 28, Issue 1, 75-96. Abstract
9 Davey, R & Parkhill, F (2012). Raising adolescent reading achievement: The use of sub-titled popular movies and high interest literacy activities. English in Aotearoa, No. 78, Oct 2012: 61-71. Abstract
10 Collins, Robert Keith (2013). Using Captions to Reduce Barriers to Native American Student Success. American Indian Culture and Research Journal, October 2013. Abstract
11 Borgaonkar, Rucha (2013). Captioning for Classroom Lecture Videos. Masters thesis, University of Houston, December 2013. Abstract
12 Bird, Stephen A. & Williams, John N. (2002). The effect of bimodal input on implicit and explicit memory: An investigation into the benefits of within-language subtitling. Applied Psycholinguistics, 23, 509-533. Abstract
13 Kruger, Jan-Louis & Steyn, Faans (2013). Subtitles and Eye Tracking: Reading and Performance. Reading Research Quarterly, 49(1), 105-120. Full article
14 Hinkin, Michael P., Harris, Richard J., & Miranda, Andrew T. (2014). Verbal Redundancy Aids Memory for Filmed Entertainment Dialogue. The Journal of Psychology, 148(2), 161-176. Abstract