Abstract
Working memory means a lot in incidental vocabulary learning and retention. The present study examines the correlation between two types of working memory—complex working memory and phonological short-term memory—and incidental vocabulary learning from captioned videos. After conducting an empirical research to 125 young learners of English as a foreign language with two working memory tests: an operation span test, which measured complex working memory, and a non-word repetition test, which measured phonological short-term memory. It showed that complex working memory did not significantly predict the effects of captioning types on incidental vocabulary learning and retention. However, phonological working memory significantly affects incidental vocabulary learning and retention. The findings suggest that the role of working memory varies as a function of captioning types. Complex working memory and phonological short-term memory may have different predictive effects in incidental vocabulary learning and retention under different captioning types.