This study investigated whether recasts provided during communicative interaction may
improve Korean EFL learners’ accuracy with regard to regular and irregular English past tense
forms, and whether individual differences in working memory capacity may intervene in the
effects of recasts. To this end, forty-two Korean university students were placed into either the
recast or the control group, and took the pretest and two types of working memory tests:
phonological short-term and verbal. The learners participated in one-on-one conversational
interactions with the researcher in three two-way communicative tasks one at a time on a
weekly basis. Only the treatment group received explicit recasts on their past tense errors while
the control group received no feedback of any kind. Finally, they took the posttest and
completed the exit questionnaire. Results showed that recasts were beneficial for raising the
learners’ accuracy level of English past tense forms, both regular and irregular, though the
effects were much larger for the irregular forms. The improvements were not significantly
correlated with neither of the working memory measures. Explicit and intensive recasting alone
was sufficient in improving EFL learners’ English past tense accuracy in this one-on-one
communicative interaction setting.