Input Modality and Working Memory Capacity: Effects on the Acquisition of Receptive and Productive Vocabulary Knowledge

Research on relationships between textual and textual-plus-pictorial gloss types and working memory capacity has been limited at best. This study examined the degree to which these two gloss types and working memory capacity (WMC), assessed through a listening span task mediate vocabulary learning. 204 English as a Foreign Language (EFL) learners listened to a text with an unfamiliar topic, before and after which they completed a vocabulary test based on Paribakht and Wesche's (1997) Vocabulary Knowledge Scale to examine their receptive versus productive vocabulary acquisition. While listening to the text, they received the meanings of twenty selected words through two different gloss types. The results revealed that textual-plus-pictorial glosses led to significantly higher increases in both receptive and productive knowledge. As for the predictive power of working memory capacity, linear regression analysis indicated that WMC did not play a role in receptive vocabulary acquisition in either of the input modes, whereas productive gain scores for both gloss types were equally, albeit insignificantly, predicted by WMC. However, no interaction between WMC and the modality effect was observed. This study confirms the modality effect on intentional vocabulary learning and suggests that the role of WMC is not mediated by gloss types.